alloy stack-ups containing at least one cast alloy because of the relatively fast solidification rates inherent in resistance spot welding. Further strengthening due to the formation of intermetallic particles within the aluminum-silicon eutectic region was found in the Aural-2-T7 to AA5754-O and Aural-2-T7 to AA6022-T4 dissimilar spot welds. The formation of the intermetallic particles was caused by the alloying between the dissimilar metal substrate materials; thus, the extent of strengthening is a function of the weld nugget diameter and relative amounts of penetration, as well as the alloy composition of the base materials. The authors gratefully acknowledge the financial support from the Canadian Federal Government Inter-departmental Program for Energy R&D, General Motors Canada, and Canmet- MATERIALS, and Natural Resources Canada. The authors are grateful for help from Prof. In-Ho Jung (McGill University) on phase diagram analysis, and Jie Liang and Cathy Bibby (CanmetMATERIALS) on mechanical testing and TEM work. 1. Patrick, E. P., and Sharp, M. L. 1992. Joining aluminum auto body structure, SAE paper 920282, SAE International, Warrendale, Pa. 2. Meschut, G., Janzen, V., and Olfermann, T. 2014. Innovative and highly productive joining technologies for multi-material lightweight car body structures. Journal of Materials Engineering and Performance 23(5): 1515 –1523. 3. Sigler, D. R., Schroth, J. G., and Karagoulis, M. J. 2012. Weld electrode for attractive weld appearance. U.S. Patent 8,222,560. July 17, 2012. 4. Sigler, D. R., Schroth, J. G., Karagoulis, M. J., and Zuo, D. New electrode weld face geometries for spot welding aluminum. Conference Proceedings, AWS Sheet Metal Welding Conference XIV, May 11–14, 2010, Livonia, Mich., pp. 1–19. 5. Sigler, D. R., Carlson, B. E., and Janiak, P. 2013. Improving aluminum resistance WELDING RESEARCH spot welding in automotive structures. Welding Journal 92(6): 64–72. 6. Yang, Y. P., Gould, J., Peterson, W., Orth, F., Zelenak, P., and Al-Fakir, W. 2013. Development of spot failure parameters for full vehicle crash modeling. Science and Technology of Welding and Joining 18(3): 222–231. 7. Zhou, M., Hu, S. J., and Zhang, H. 1999. Critical specimen sizes for tensileshear testing of steel sheets. Welding Journal 78(9): 305-s to 313-s. 8. Chao, Y. J. 2003. Ultimate strength and failure mechanism of resistance spot weld subjected to tensile, shear, or combined tensile/shear loads. J. Eng. Mater. Technol. :125125–132. 9. Kang, J., Wilkinson, D. S., Wu, P. D., Bruhis, M., Jain, M., Embury, J. D., and Mishra, R. K. 2008. Constitutive behavior of AA5754 sheet materials at large strains. ASME J. Eng. Mater. Technol. 130(3): 031004-1-5. 10. Kang, J., and Shen, G. 2014. A novel shear test procedure for determination of constitutive behavior of automotive aluminum alloy sheets. ASTM Selected Technical Papers, STP 1571: Application of Automation Technology in Fatigue and Fracture Testing and Analysis, pp. 50–62. 11. ASTM Standard B831-14, Standard Test Method for Shear Testing of Thin Alu- JULY 2016 / WELDING JOURNAL 255-s Fig. 13 — A — STEM bright field and corresponding EDS combination map; B — corresponding elemental maps of Aural2T7 to Aural2T7 spot weld for welding schedule 1. Fig. 14 — A — STEM bright field and corresponding EDS combination map; B — corresponding elemental maps of Aural2T7 to AA5754O spot weld. A B A B Acknowledgments References
Welding Journal | July 2016
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