The Strength and Metallography of a Bimetallic Friction Stir Bonded Joint between AA6061 and High Hardness Steel

Authors: Richard E. Miller

Abstract:

12.7-mm thick plates of 6061-T6511 aluminum alloy and high hardness steel (528 HV) were successfully joined by a friction stir bonding process using a tungsten-rhenium stir tool. Process parameter variation experiments, which included tool design geometry, plunge and traverse rates, tool offset, spindle tilt, and rotation speed, were conducted to develop a parameter set which yielded a defect free joint. Laboratory tensile tests exhibited yield stresses which exceed the strengths of comparable AA6061-to-AA6061 fusion and friction stir weld joints. Scanning electron microscopy and energy dispersive X-ray spectroscopy analysis also show atomic diffusion at the material interface region.

Keywords: Dissimilar materials, friction stir, welding.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1092299

References:

[1] W. M. Thomas, E. D. Nicholas., "Friction Stir Welding for the Transportation Industries”, Materials & Design, V.18, Iss. 4-6, 1997 pp. 269-273.
[2] M. J. Gonser, "Microstructure Evolution and Material Flow Behavior in Friction-Stir Welded Dissimilar Titanium Alloys”, (Doctoral dissertation), The Ohio State University, Columbus, OH, USA, 2010, retrieved from https://etd.ohiolink.edu/.
[3] R. E. Miller, "Preliminary Report on the Strength and Metallography of a Bimetallic Friction Stir Weld Joint Between AA6061 and MIL-DTL-46100E High Hardness Steel Armor”, NTIS Technical Report #ADA580292, 2012, retrieved from http://www.ntis.gov.
[4] ASTM B918/B918M-9: Standard Practice for Heat Treatment of Wrought Aluminum Alloys, ASTM International
[5] ASTM D1002-10:Standard Test Method for Apparent Shear Strength of Single-Lap-Joint Adhesively Bonded Metal Specimens by Tension Loading (Metal-to-Metal), ASTM International
[6] ASTM E-290-13: Standard Test Methods for Bend Testing of Material for Ductility, ASTM International.