Search results for: machining of aluminum alloy

Authors: Avadhesh Yadav, Balram Manoj Kumar

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A solar powered air heating system using parabolic trough collector was experimentally investigated. In this experimental setup, the reflected solar radiations were focused on absorber tube which was placed at focal length of the parabolic trough. In this setup, air was used as working fluid which collects the heat from absorber tube. To enhance the performance of parabolic trough, collector with different type of reflectors were used. It was observed for aluminum sheet maximum temperature is 52.3ºC, which 24.22% more than steel sheet as reflector and 8.5% more than aluminum foil as reflector, also efficiency by using Aluminum sheet as reflector compared to steel sheet as reflector is 61.18% more. Efficiency by using aluminum sheet as reflector compared to aluminum foil as reflector is 18.98% more.

Keywords: parabolic trough collector, reflectors, air flow rates, solar power, aluminum sheet

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Authors: M. Sandeep Kumar, Vasu Velagapudi, A. Venugopal

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When machining is carried out on a workpiece, residual stresses are induced in the workpiece due to nonuniform thermal and mechanical loads. These stresses play a vital role in the surface integrity of the final product or the output. Inconel 718 is commonly used in critical structural components of aircraft engines due to its properties at high temperatures. Therefore it is important to keep down the stresses induced due to machining. This can be achieved through proper lubricating conditions. In this work, experiments were carried out to check the influence of the developed nanofluid as cutting fluids on residual stresses developed during the course of machining. The results of MQL/Nanofluids were compared with MQL/Vegetable oil and dry machining lubricating condition. Results indicate the reduction in residual stress with the use of MQL/Nanofluid.

Keywords: nanofluids, MQL, residual stress, Inconel-718

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Authors: Siamak Ghorbani, Nikolay Ivanovich Polushin

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Chatter vibrations, occurring during cutting process, cause vibration between the cutting tool and workpiece, which deteriorates surface roughness and reduces tool life. The purpose of this study is to investigate the influence of cutting parameters and tool construction on surface roughness and vibration in turning of aluminum alloy AA2024. A new design of cutting tool is proposed, which is filled up with epoxy granite in order to improve damping capacity of the tool. Experiments were performed at the lathe using carbide cutting insert coated with TiC and two different cutting tools made of AISI 5140 steel. Taguchi L9 orthogonal array was applied to design of experiment and to optimize cutting conditions. By the help of signal-to-noise ratio and analysis of variance the optimal cutting condition and the effect of the cutting parameters on surface roughness and vibration were determined. Effectiveness of Taguchi method was verified by confirmation test. It was revealed that new cutting tool with epoxy granite has reduced vibration and surface roughness due to high damping properties of epoxy granite in toolholder.

Keywords: ANOVA, damping capacity, surface roughness, Taguchi method, vibration

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Authors: Young Jun Lee, Tae Hyuk Lee, Kyoung Tae Park, Jong Hyeon Lee

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The harsh atmosphere of the sulfur-iodine process used for producing hydrogen requires better corrosion resistance and mechanical properties that is possible to obtain with pure tantalum. Ta-W alloy is superior to pure tantalum but is difficult to alloy due to its high melting temperature. In this study, substrates of near-net shape (Swagelok® tube ISSG8UT4) were coated with Ta-W using the multi-anode reactive alloy coating (MARC) process in molten salt (LiF-NaF-K2TaF7) at different current densities (1, 2 and 4mA/cm2). Ta-4W coating films of uniform coating thicknesses, without any entrapped salt, were successfully deposited on Swagelok tube by electrodeposition at 1 mA/cm2. The resulting coated film with a corrosion rate of less than 0.011 mm/year was attained in hydriodic acid at 160°C, and hardness up to 12.9 % stronger than pure tantalum coated film. The alloy coating films also contributed to significant enhancement of corrosion resistance.

Keywords: tantalum, tantalum alloy, tungsten alloy, electroplating

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Authors: Vineeth G. Kuriakose, Joseph C. Chen, Ye Li

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The research follows a systematic approach to optimize the parameters for parts machined by turning and milling processes. The quality characteristic chosen is surface roughness since the surface finish plays an important role for parts that require surface contact. A tapered cylindrical surface is designed as a test specimen for the research. The material chosen for machining is aluminum alloy 6061 due to its wide variety of industrial and engineering applications. HAAS VF-2 TR computer numerical control (CNC) vertical machining center is used for milling and HAAS ST-20 CNC machine is used for turning in this research. Taguchi analysis is used to optimize the surface roughness of the machined parts. The L₉ Orthogonal Array is designed for four controllable factors with three different levels each, resulting in 18 experimental runs. Signal to Noise (S/N) Ratio is calculated for achieving the specific target value of 75 ± 15 µin. The controllable parameters chosen for turning process are feed rate, depth of cut, coolant flow and finish cut and for milling process are feed rate, spindle speed, step over and coolant flow. The uncontrollable factors are tool geometry for turning process and tool material for milling process. Hypothesis testing is conducted to study the significance of different uncontrollable factors on the surface roughnesses. The optimal parameter settings were identified from the Taguchi analysis and the process capability C_p and the process capability index C_pk were improved from 1.76 and 0.02 to 3.70 and 2.10 respectively for turning process and from 0.87 and 0.19 to 3.85 and 2.70 respectively for the milling process. The surface roughnesses were improved from 60.17 µin to 68.50 µin, reducing the defect rate from 52.39% to 0% for the turning process and from 93.18 µin to 79.49 µin, reducing the defect rate from 71.23% to 0% for the milling process. The purpose of this study is to efficiently utilize the Taguchi design analysis to improve the surface roughness.

Keywords: surface roughness, Taguchi parameter design, CNC turning, CNC milling

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Authors: V. Singh, S. Singh, S. S. Garewal

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Metal matrix composites with aluminum as the matrix material have been heralded as the next great development in advanced engineering materials. Aluminum metal matrix composites (AMMC) refer to the class of light weight high performance material systems. Properties of AMMCs can be tailored to the demands of different industrial applications by suitable combinations of matrix, reinforcement and processing route. AMMC finds its application in automotive, aerospace, defense, sports and structural areas. This paper presents an overview of AMMC material systems on aspects relating to processing, types and applications with case studies.

Keywords: aluminum metal matrix composites, applications of aluminum metal matrix composites, lighting material processing of aluminum metal matrix composites

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Authors: Rahul R. Gurpude, Pallvita Yadav, Amrut Mulay

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In recent years, there has been a growing focus on advanced manufacturing processes, and one such emerging process is wire electric discharge machining (WEDM). WEDM is a precision machining process specifically designed for cutting electrically conductive materials with exceptional accuracy. It achieves material removal from the workpiece metal through spark erosion facilitated by electricity. Initially developed as a method for precision machining of hard materials, WEDM has witnessed significant advancements in recent times, with numerous studies and techniques based on electrical discharge phenomena being proposed. These research efforts and methods in the field of ED encompass a wide range of applications, including mirror-like finish machining, surface modification of mold dies, machining of insulating materials, and manufacturing of micro products. WEDM has particularly found extensive usage in the high-precision machining of complex workpieces that possess varying hardness and intricate shapes. During the cutting process, a wire with a diameter ranging from 0.18mm is employed. The evaluation of EDM performance typically revolves around two critical factors: material removal rate (MRR) and surface roughness (SR). To comprehensively assess the impact of machining parameters on the quality characteristics of EDM, an Analysis of Variance (ANOVA) was conducted. This statistical analysis aimed to determine the significance of various machining parameters and their relative contributions in controlling the response of the EDM process. By undertaking this analysis, optimal levels of machining parameters were identified to achieve desirable material removal rates and surface roughness.

Keywords: WEDM, MRR, optimization, surface roughness

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Authors: Jung-Ho Moon, Tae Kwon Ha

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The effect of Yttrium addition on the microstructure and mechanical properties of Sn-Zn eutectic alloy, which has been attracting intensive focus as a Pb-free solder material, was investigated in this study. Phase equilibrium has been calculated by using FactSage® to evaluate the composition and fraction of equilibrium intermetallic compounds and construct a phase diagram. In the case of Sn-8.8 Zn eutectic alloy, the as-cast microstructure was typical lamellar. With addition of 0.25 wt. %Y, a large amount of pro-eutectic phases have been observed and various YZnx intermetallic compounds were expected to successively form during cooling. Hardness of Sn-8.8 Zn alloy was not affected by Y-addition and both alloys could be rolled by 90% at room temperature.

Keywords: Sn-Zn eutectic alloy, yttrium, FactSage®, microstructure, mechanical properties

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Authors: S. M. A. Al Qawabah, A. I. O. Zaid

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Al-4%Cu alloys are now widely used in many engineering applications especially in robotic, aerospace and vibration control area. The main problem arises from the weakness of their mechanical characteristics. Therefore, this study is directed towards enhancing the mechanical properties through severe plastic deformation. In this work, the hot direct extrusion process was chosen to provide the required hot work for this purpose. A direct extrusion die was designed and manufactured to be used in this investigation. The general microstructure, microhardness, surface roughness, and compression tests were performed on specimens from the produced Al-4%Cu alloy both in the as cast and after extrusion conditions. It was found that a pronounced enhancement in the mechanical characteristics of the produced Al-4%Cu after extrusion was achieved. The microhardness increased by 89.3%, the flow stress was decreased by 10% at 0.2 strain and finally the surface roughness was reduced by 81.6%.

Keywords: aluminum, copper, surface roughness, hot extrusion

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Authors: Nikolay Konukhov

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This paper to report on a new analytic model for predicting microcontact resistance and the design, fabrication, and testing of microelectromechanical systems (MEMS) metal contact switches with sputtered bimetallic (i.e., gold (Au)-on-Au-platinum (Pt), (Au-on-Au-(6.3at%)Pt)), binary alloy (i.e., Au-palladium (Pd), (Au-(3.7at%)Pd)), and ternary alloy (i.e., Au-Pt-copper (Cu), (Au-(5.0at%)Pt-(0.5at%)Cu)) electric contacts. The microswitches with bimetallic and binary alloy contacts resulted in contact resistance values between 1–2

Keywords: alloys, electric contacts, microelectromechanical systems (MEMS), microswitch

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Authors: Madhu Sarwan, Ritu Dubey, Sadhna Singh

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We have investigated the structural phase transition from Zinc-Blende (ZB) to Rock-Salt (RS) structure of TlxGa1-xAs by using Interaction Potential Model (IPM). The IPM consists of Coulomb interaction, Three-Body Interaction (TBI), Van Der Wall (vdW) interaction and overlap repulsive short range interaction. The structural phase transition has been computed by using the vegard’s law. The volume collapse is also computed for this alloy. We have also investigated the second order elastic constants with composition for the alloy TlxGa1-xAs.

Keywords: III-V alloy, elastic moduli, phase transition, semiconductors

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Authors: Fisseha Zewdie, Naresh Bhatnagar

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Lightweight and strong aluminum foam is developed by reinforcing Al-Si-Cu alloy (LM24) with Cermet Hollow Spheres (CHS) as porous creating agents. The foam samples were prepared by mixing the CHS in molten LM24 at 750°C, using gravity and stir casting. The CHSs were fabricated using a blend of silicon carbide and stainless-steel powders using the powder metallurgy technique. It was found that CHS reinforcement greatly enhances the performance of the composite metal foam, making it suitable for high impact loading applications such as crash protection and shock absorption. This study examined the strength, density, energy absorption and possible applications of the new aluminum foam. The results revealed that the LM24 foam reinforced with the CHS has the highest energy absorption of about 88 MJ/m3 among all categories of foam samples tested. Its density was found to be 1.3 g/cm3, while the strength, densification strains and porosity were 420 MPa, 34% and 70%, respectively. Besides, the matrix and reinforcement's microstructure, chemical composition, X-ray diffraction, HRTEM and related micrographic analyses are performed for characterization and verifications.

Keywords: composite metal foam, hollow spheres, gravity casting, energy absorption

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Authors: Ji Chan Kim, Seok Hong Min, Tae Kwon Ha

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The effect of Yttrium addition on the microstructure and mechanical properties of Sn-Zn eutectic alloy, which has been attracting intensive focus as a Pb-free solder material, was investigated in this study. Phase equilibrium has been calculated by using FactSage® to evaluate the composition and fraction of equilibrium intermetallic compounds and construct a phase diagram. In the case of Sn-8.8 Zn eutectic alloy, the as-cast microstructure was typical lamellar. With addition of 0.25 wt. %Y, a large amount of pro-eutectic phases have been observed and various YZnx intermetallic compounds were expected to successively form during cooling. Hardness of Sn-8.8 Zn alloy was not affected by Y-addition and both alloys could be rolled by 90% at room temperature.

Keywords: lead-free solder, zn-al-sn alloy, phase equilibrium, rolling, microstructure, hardness

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Authors: Hisashi Imai, Kuan-Yu Chen, Katsuyoshi Kondoh, Hung-Yin Tsai, Junko Umeda

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Microstructural and electrical properties of copper-chromium alloy (Cu-Cr) dispersed with vapor-grown carbon fiber (VGCF) prepared by powder metallurgy (P/M) process have been investigated. Cu-0.7 mass% Cr pre-alloyed powder (Cu-Cr) made by water atomization process was used as raw materials, which contained solid solute Cr elements in Cu matrix. The alloy powder coated with un-bundled VGCF by using oil coating process was consolidated at 1223 K in vacuum by spark plasma sintering, and then extruded at 1073 K. The extruded Cu-Cr alloy (monolithic alloy) had 209.3 MPa YS and 80.4 IACS% conductivity. The extruded Cu-Cr with 0.1 mass% VGCF composites revealed a small decrease of YS compared to the monolithic Cu-Cr alloy. On the other hand, the composite had a higher electrical conductivity than that of the monolithic alloy. For example, Cu-Cr with 0.1 mass% VGCF composite sintered for 5 h showed 182.7 MPa YS and 89.7 IACS% conductivity. In the case of Cu-Cr with VGCFs composites, the Cr concentration was observed around VGCF by SEM-EDS analysis, where Cr23C6 compounds were detected by TEM observation. The amount of Cr solid solution in the matrix of the Cu-Cr composites alloy was about 50% compared to the monolithic Cu-Cr sintered alloy, and resulted in the remarkable increment of the electrical conductivity.

Keywords: powder metallurgy Cu-Cr alloy powder, vapor-grown carbon fiber, electrical conductivity

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Authors: Gurjinder Singh Randhawa, Jonny Garg, Sukhraj Singh, Gurmeet Singh Cheema

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A major problem related to the use of rotavator is wear of rotavator blades due to abrasion by soil hard particles, as it seriously affects tillage quality and agricultural production economy. The objective of this study was to increase the wear resistance by covering the rotavator blades with two different hard facing electrodes. These blades are generally produced from low carbon or low alloy steel. During the field work i.e. preparing land for the cultivation these blades are subjected to severe wear conditions. Comparative wear tests on a regular rotavator blade and two kinds of hardfacing with electrodes were conducted in the field. These two different hardfacing electrodes, which are designated HARD ALLOY-400 and HARD ALLOY-650, were used for hardfacing. The wear rate in the field tests was found to be significantly different statistically. When the cost is taken into consideration; HARD ALLOY-650 and HARD ALLOY-400 have been found to be the best hardfacing electrodes.

Keywords: hardfacing, rotavator blades, hard alloy-400, abrasive wear

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Authors: D. Miroud, H. Mokaddem, M. Tata, N. Foucha

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The body of PDC (polycrystalline diamond compact) drill bit can be manufactured from two different materials, steel and tungsten carbide matrix. Commonly the steel body is produced by machining, thermal spraying a bonding layer and hardfacing of Ni-based matrix reinforced with fused eutectic tungsten carbide (WC/W2C). The matrix body bit is manufactured by infiltrating tungsten carbide particles, with a Copper binary or ternary alloy. By erosion-corrosion mechanisms, the PDC drill bits matrix undergoes severe damage, occurring particularly around the PDC inserts and near injection nozzles. In this study, we investigated the possibility to repair the damaged matrix regions by hardfacing technic. Ni-based hardfacing alloy reinforced with fused eutectic tungsten carbide is deposited on infiltrated WC-W-Ni substrate by oxyacetylene welding (OAW). The microstructure at the hardfacing / matrix interface is characterized by SEM- EDS, XRD and micro hardness Hv0.1. The hardfacing conditions greatly affect the dilution phenomenon and the distribution of carbides at the interface, without formation of transition zone. During OAW welding deposition, interdiffusion of atoms occurs: Cu and Sn diffuse from infiltrated matrix substrate into hardfacing and simultaneously Cr and Si alloy elements from hardfacing diffuse towards the substrate. The dilution zone consists of a nickel-rich phase with a heterogeneous distribution of eutectic spherical (Ni-based hardfacing alloy) and irregular (matrix) WC/W2C carbides and a secondary phase rich in Cr-W-Si. Hardfacing conditions cause the dissolution of banding around both spherical and irregular carbides. The micro-hardness of interface is significantly improved by the presence of secondary phase in the inter-dendritic structure.

Keywords: dilution, dissolution, hardfacing, infiltrated matrix, PDC drill bits

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Authors: Gyung Soo Jeon, Hong Bae Kim, Chi Jung Oh

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In order to prepare the α-alumina with low content of sodium oxide from aluminum trihydroxide as a reactant, three kinds of methods were employed as follows; the mixture of Chamotte (aggregate composed of silica and alumina), ammonium chloride and aluminum fluoride with aluminum trihydroxide under 1600°C, respectively. The sodium oxide in α-alumina produced above methods was analyzed by XRF and the particle size distribution was determined by particle size analyzer, and the specific surface area of α-alumina was measured by BET method, and phase of α-alumina produced was confirmed by XRD. Acknowledgement: This research was supported by Development Program of Technical Innovation funded by Korea Technology and Information Promotion Agency for SMEs (KTIP-2016-S2401821).

Keywords: α-alumina, sodium oxide, aluminum trihydroxide, Chamotte, ammonium chloride, aluminum fluoride

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Authors: Weinian Wang, Joseph C. Chen

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The objective of this research is to optimize the process of cutting cylindrical workpieces utilizing live tooling on a HAAS ST-20 lathe. Surface roughness (Ra) has been investigated as the indicator of quality characteristics for machining process. Aluminum alloy was used to conduct experiments due to its wide range usages in engineering structures and components where light weight or corrosion resistance is required. In this study, Taguchi methodology is utilized to determine the effects that each of the parameters has on surface roughness (Ra). A total of 18 experiments of each process were designed according to Taguchi’s L9 orthogonal array (OA) with four control factors at three levels of each and signal-to-noise ratios (S/N) were computed with Smaller the better equation for minimizing the system. The optimal parameters identified for the surface roughness of the turning operation utilizing live tooling were a feed rate of 3 inches/min(A3); a spindle speed of 1300 rpm(B3); a 2-flute titanium nitrite coated 3/8” endmill (C1); and a depth of cut of 0.025 inches (D2). The mean surface roughness of the confirmation runs in turning operation was 8.22 micro inches. The final results demonstrate that Taguchi methodology is a sufficient way of process improvement in turning process on surface roughness.

Keywords: CNC milling operation, CNC turning operation, surface roughness, Taguchi parameter design

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Authors: Wenbo Yu, Zihao Yuan, Zhipeng Guo, Shoumei Xiong

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Under different slow shot speeds in vacuum assisted high pressure die casting (VHPDC) process, plate-shaped specimens of hypereutectic A390 aluminum alloy were produced. According to the results, the vacuum pressure inside the die cavity increased linearly with the increasing slow shot speed at the beginning of mold filling. Meanwhile, it was found that the tensile properties of vacuum die castings were deteriorated by the porosity content. In addition, the average primary Si size varies between 14µm to 23µm, which has a binary functional relationship with the slow shot speeds. Due to the vacuum effect, the castings were treated by T6 heat treatment. After heat treatment, microstructural morphologies revealed that needle-shaped and thin-flaked eutectic Si particles became rounded while Al2Cu dissolved into α-Al matrix. For the as-received sample in-situ tensile test, microcracks firstly initiate at the primary Si particles and propagated along Al matrix with a transgranular fracture mode. In contrast, for the treated sample, the crack initiated at the Al2Cu particles and propagated along Al grain boundaries with an intergranular fracture mode. In-situ three bending test, microcracks firstly formed in the primary Si particles for both samples. Subsequently, the cracks between primary Si linked along Al grain boundaries in as received sample. In contrast, the cracks in primary Si linked through the solid lines in Al matrix. Furthermore, the fractography revealed that the fracture mechanism has evolved from brittle transgranular fracture to a fracture mode with many dimples after heat treatment.

Keywords: A390 aluminum, vacuum assisted high pressure die casting, heat treatment, mechanical properties

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Authors: Arnold S. Freitas Neto, Rodrigo E. Coelho, Erick S. Mendonça

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The study aims to assess if high-purity iron powder in iron-aluminum alloys can be replaced by SAE 1020 steel chips with an atomicity proportion of 50% for each element. Chips of SAE 1020 are rejected in industrial processes. Thus, the use of SAE 1020 as a replaceable composite for iron increase the sustainability of ferrous alloys by recycling industrial waste. The alloys were processed by high energy milling, of which the main advantage is the minimal loss of raw material. The raw material for three of the six samples were high purity iron powder and recyclable aluminum cans. For the other three samples, the high purity iron powder has been replaced with chips of SAE 1020 steel. The process started with the separate milling of chips of aluminum and SAE 1020 steel to obtain the powder. Subsequently, the raw material was mixed in the pre-defined proportions, milled together for five hours and then underwent a closed-die hot compaction at the temperature of 500 °C. Thereafter, the compacted samples underwent heat treatments known as sintering and solubilization. All samples were sintered one hour, and 4 samples were solubilized for either 4 or 10 hours under well-controlled atmosphere conditions. Lastly, the composition and the mechanical properties of their hardness were analyzed. The samples were analyzed by optical microscopy, scanning electron microscopy and hardness testing. The results of the analysis showed a similar chemical composition and interesting hardness levels with low standard deviations. This verified that the use of SAE 1020 steel chips can be a low-cost alternative for high-purity iron powder and could possibly replace high-purity Iron in industrial applications.

Keywords: Fe-Al alloys, high energy milling, iron-aluminum alloys, metallography characterization, powder metallurgy, recycling ferrous alloy, SAE 1020 steel recycling

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Authors: Dong-Keun Jeong, Jong-Hyun Kim, Woon-Ha Yoon, Hee-Je Kim

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In order to automatically operate the ultrasonic transducer drive system for sonicating aluminum, this paper proposes the ultrasonic transducer sensorless control algorithm. The resonance frequency shift and electrical impedance change is a common phenomenon in the state of the ultrasonic transducer. The proposed control algorithm make use of the impedance change of ultrasonic transducer according to the environment between air state and aluminum alloy state, it controls the ultrasonic transducer drive system autonomous without a sensor. The proposed sensorless autonomous ultrasonic transducer control algorithm was experimentally verified using a 3kW prototype ultrasonic transducer drive system.

Keywords: ultrasonic transducer drive system, impedance change, sensorless, autonomous control algorithm

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Authors: Mohammad M. Khan, Pankaj Agarwal

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The present investigation deals with the microstructures, mechanical and detailed wear characteristics of in situ TiC particles reinforced zinc aluminum-based metal matrix composites. The composites have been synthesized by liquid metallurgy route using vortex technique. The composite was found to be harder than the matrix alloy due to high hardness of the dispersoid particles therein. The former was also lower in ultimate tensile strength and ductility as compared to the matrix alloy. This could be explained to be due to the use of coarser size dispersoid and larger interparticle spacing. Reasonably uniform distribution of the dispersoid phase in the alloy matrix and good interfacial bonding between the dispersoid and matrix was observed. The composite exhibited predominantly brittle mode of fracture with microcracking in the dispersoid phase indicating effective easy transfer of load from matrix to the dispersoid particles. To study the wear behavior of the samples three different types of tests were performed namely: (i) sliding wear tests using a pin on disc machine under dry condition, (ii) high stress (two-body) abrasive wear tests using different combinations of abrasive media and specimen surfaces under the conditions of varying abrasive size, traversal distance and load, and (iii) low-stress (three-body) abrasion tests using a rubber wheel abrasion tester at various loads and traversal distances using different abrasive media. In sliding wear test, significantly lower wear rates were observed in the case of base alloy over that of the composites. This has been attributed to the poor room temperature strength as a result of increased microcracking tendency of the composite over the matrix alloy. Wear surfaces of the composite revealed the presence of fragmented dispersoid particles and microcracking whereas the wear surface of matrix alloy was observed to be smooth with shallow grooves. During high-stress abrasion, the presence of the reinforcement offered increased resistance to the destructive action of the abrasive particles. Microcracking tendency was also enhanced because of the reinforcement in the matrix. The negative effect of the microcracking tendency was predominant by the abrasion resistance of the dispersoid. As a result, the composite attained improved wear resistance than the matrix alloy. The wear rate increased with load and abrasive size due to a larger depth of cut made by the abrasive medium. The wear surfaces revealed fine grooves, and damaged reinforcement particles while subsurface regions revealed limited plastic deformation and microcracking and fracturing of the dispersoid phase. During low-stress abrasion, the composite experienced significantly less wear rate than the matrix alloy irrespective of the test conditions. This could be explained to be due to wear resistance offered by the hard dispersoid phase thereby protecting the softer matrix against the destructive action of the abrasive medium. Abraded surfaces of the composite showed protrusion of dispersoid phase. The subsurface regions of the composites exhibited decohesion of the dispersoid phase along with its microcracking and limited plastic deformation in the vicinity of the abraded surfaces.

Keywords: abrasive wear, liquid metallurgy, metal martix composite, SEM

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Authors: James S. Kwame, E. Yakushina, P. Blackwell

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The challenges in forming titanium alloys at room temperature are well researched and are linked both to the limitations imposed by the basic crystal structure and their ability to form texture during plastic deformation. One major issue of concern for the sheet forming of titanium alloys is their high sensitivity to surface inhomogeneity. Various machining processes are utilised in preparing sheet hole edges for edge flanging applications. However, the response of edge forming tendencies of titanium to different edge surface finishes is not well investigated. The hole expansion test is used in this project to elucidate the impact of abrasive water jet (AWJ) and electro-discharge machining (EDM) cutting techniques on the edge formability of CP-Ti (Grade 2) and Ti-3Al-2.5V alloys at room temperature. The results show that the quality of the edge surface finish has a major effect on the edge formability of the materials. The work also found that the variations in the edge forming performance are mainly the result of the influence of machining induced edge surface defects.

Keywords: titanium alloys, hole expansion test, edge formability, non-conventional machining

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Authors: Amer Momani, Tarek Al-Hawari, Abdallah Alakayleh

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This study explains how to construct an actionable activity-based costing and management system to accurately track and account the total costs of architectural aluminum projects. Two ABC models were proposed to accomplish this purpose. First, the learning and development model was introduced to examine how to apply an ABC model in an architectural aluminum firm for the first time and to be familiar with ABC concepts. Second, an actual ABC model was built on the basis of the results of the previous model to accurately trace the actual costs incurred on each project in a year, and to be able to provide a quote with the best trade-off between competitiveness and profitability. The validity of the proposed model was verified on a local architectural aluminum company.

Keywords: activity-based costing, activity-based management, construction, architectural aluminum

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Authors: B. Oji, O. Olaniran

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The prospect of improving the corrosion property of Al 6063 alloy based hybrid composites reinforced with cassava peel ash (CPA) and silicon carbide (SiC) is the target of this research. It seeks to determine the viability of using locally sourced material (CPA) as a complimentary reinforcement for SiC to produce low cost high performance aluminum matrix composite. The CPA was mixed with the SiC in the ratios 0:1, 1:3, 1:1, 3:1 and 1:0 for 8 wt % reinforcement in the produced composites by double stir-casting method. The microstructures of the composites were studied before and after corrosion using the scanning electron microscopy which reveals the matrix (dark region) and eutectic phase (lamellar region). The corrosion rate was studied in accordance with ASTM G59-97 (2014) using an AutoLab potentiostat (Versa STAT 400) with versaSTUDIO electrochemical software which analyses the results obtained. The result showed that Al 6063 alloy exhibited good corrosion resistance in 0.3M H₂SO₄ and 3.5 wt. % NaCl solutions with sample C containing the 25% wt CPA showing the highest resistance to corrosion with corrosion rate of 0.0046 mmpy as compared to the control sample which has a value of 13.233 mmpy. Sample B, D, E, and F also showed a corrosion rate of 3.9502, 2.6903, 2.1223, and 5.7344 mmpy which indicated a better corrosion rate than the control in the acidic environment. The corrosion rate in the saline medium shows that sample E with 75% wt CPA has the lowest corrosion rate of 0.0422 mmpy as compared to the control sample with 0.0873 mmpy corrosion rate.

Keywords: Al-Mg-Si alloy, AutoLab potentiostat, Cassava Peel Ash, CPA, hybrid composite, stir-cast method

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Authors: Gurjinder Singh, Ankur Gill, Amardeep Singh Kang

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In the present work an effort has been made to study the influence of the welding parameters on tensile strength of friction stir welding of aluminum. Three process parameters tool rotation speed, welding speed, and shoulder diameter were selected for the study. Two level factorial design of eight runs was selected for conducting the experiments. The mathematical model was developed from the data obtained. The significance of coefficients and adequacy of developed models were tested by ‘t’ test and ‘F’ test respectively. The effects of process parameters on mechanical properties have been represented in the form of graphs for better understanding.

Keywords: friction stir welding, aluminium alloy, mathematical model, welding speed

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Authors: H. Zengin, M. E. Turan, Y. Turen, H. Ahlatci, Y. Sun

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This study aimed for improving wear resistance of AM60 magnesium alloy by Ti addition (0, 0.2, 0.5, 1wt%Ti). An electric resistance furnace was used to produce alloys. Pure Mg together with Al, Al-Ti and Al-Mn were melted at 750 ⁰C in a stainless steel crucible under controlled Ar gas atmosphere and then poured into a metal mould preheated at 250 ⁰C. Microstructure characterizations were performed by light optical (LOM) and scanning electron microscope (SEM) after the wear test. Wear rates and friction coefficients were measured with a pin-on-disk type UTS-10 Tribometer test device under a load of 20N. The results showed that Ti addition altered the morphology and the amount of b-Mg₁₇Al₁₂ phase in the microstructure of AM60 alloy. b-Mg₁₇Al₁₂ phases on the grain boundaries were refined with increasing amount of Ti. An improvement in wear resistance of AM60 alloy was observed due to the alteration in the microstructure by Ti addition.

Keywords: magnesium alloy, titanium, SEM, wear

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Authors: Anand Prakash Dwivedi, Sounak Kumar Choudhury

Abstract:

Electric Discharge Machining (EDM) is a well-established and one of the most primitive unconventional manufacturing processes, that is used world-wide for the machining of geometrically complex or hard and electrically conductive materials which are extremely difficult to cut by any other conventional machining process. One of the major flaws, over all its advantages, is its very slow Material Removal Rate (MRR). In order to eradicate this slow machining rate, various researchers have proposed various methods like; providing rotational motion to the tool or work-piece or to both, mixing of conducting additives (such as SiC, Cr, Al, graphite etc) powders in the dielectric, providing vibrations to the tool or work-piece or to both etc. Present work is a comparative study of Rotational and Stationary Tool EDM, which deals with providing rotational motion to the copper tool for the machining of AISI D3 Tool Steel and the results have been compared with stationary tool EDM. It has been found that the tool rotation substantially increases the MRR up to 28%. The average surface finish increases around 9-10% by using the rotational tool EDM. The average tool wear increment is observed to be around 19% due to the tool rotation. Apart from this, the present work also focusses on the recast layer analysis, which are being re-deposited on the work-piece surface during the operation. The recast layer thickness is less in case of Rotational EDM and more for Stationary Tool EDM. Moreover, the cracking on the re-casted surface is also more for stationary tool EDM as compared with the rotational EDM.

Keywords: EDM, MRR, Ra, TWR

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Authors: Manjinder Bajwa, Mahipal Singh, Manish Nagpal

Abstract:

This research paper aims to propose a novel approach using ANOVA technique for the strategic investigation of process parameters and their effects on the mechanical properties of Aluminium alloy cast. The two process parameters considered here were permeability of sand and pouring temperature of aluminium alloy. ANOVA has been employed for the first time to determine the effects of these selected parameters on the impact strength of alloy. The experimental results show that this proposed technique has great potential for analyzing sand casting process. Using this approach we have determined the treatment mean square, response mean square and mean square of error as 8.54, 8.255 and 0.435 respectively. The research concluded that at the 5% level of significance, permeability of sand is the more significant parameter influencing the impact strength of cast alloy.

Keywords: aluminium alloy, pouring temperature, permeability of sand, impact strength, ANOVA

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Authors: Nurul Na'imy Wan, Mohamad Sazali Said, Jaharah Ab. Ghani, Mohd Asri Selamat

Abstract:

This paper presents the surface roughness of the Aluminium silicon alloy (AlSi) matrix composite which has been reinforced with aluminium nitride (AlN), with three types of carbide inserts. Experiments were conducted at various cutting speeds, feed rates, and depths of cut, according to the Taguchi method, using a standard orthogonal array L27 (34). The signal-to-noise (S/N) ratio and analysis of variance are applied to study the characteristic performance of machining parameters in measuring the surface roughness during the milling operation. The analysis of results, using the Taguchi method concluded that a combination of low feed rate, medium depth of cut, low cutting speed, and insert TiB2 give a better value of surface roughness. From Taguchi method, it was found that cutting speed of 230m/min, feed rate of 0.4 mm/tooth, depth of cut of 0.5mm and type of insert of TiB2 were the optimal machining parameters that gave the optimal value of surface roughness.

Keywords: AlSi/AlN Metal Matrix Composite (MMC), surface roughness, Taguchi method

Procedia PDF Downloads 437