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Published in:
2019 | OriginalPaper | Chapter
Effects of Post-weld Heat Treatment on Microstructure and Mechanical Behavior of Friction Stir Welded Thick Section Al–Zn–Mg–Cu Alloy
Authors : T. Ramakrishna, S. Srinivasa Rao, G. Swami Naidu
Published in: Advances in Engineering Design
Publisher: Springer Singapore
Abstract
Friction stir welding is considered to be a promising solution to successfully join high strength 7000 series aluminum alloys. However, questions related to a decrease in weld mechanical properties with an increase in plate thickness still remain unanswered. In this study, 16 mm thick AA7075–T651 aluminum alloy plates were successfully joined by friction stir welding. The welds were heat treated using a special solutionizing method called cyclic solution treatment (CST). The effects of CST on mechanical behavior and microstructures of the welds were studied using hardness, tensile, and impact tests and optical microscopy. The post-weld heat treatment significantly improves the hardness of the joint and homogenizes the hardness distribution across the welded joint. However, the tensile properties and impact toughness of the welds were not found to be beneficially affected. A significant grain growth in the weld nugget was observed after CST.
