Microstructure and mechanical properties of friction stir welded AA7075-T651 aluminum alloy thick plates

作     者：T.SRINIVASA RAO G.MADHUSUDHAN REDDY S.R.KOTESWARA RAO 

作者机构：Department of Mechanical EngineeringTagore Engineering College Metal Joining GroupDefense Metallurgical Research Laboratory Department of Mechanical EngineeringSSN College of Engineering 

出 版 物：《Transactions of Nonferrous Metals Society of China》 (中国有色金属学报（英文版）)

年 卷 期：2015年第25卷第6期

页      面：1770-1778页

核心收录：

学科分类：080503[工学-材料加工工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 080201[工学-机械制造及其自动化] 

基　　金：financial support from Armament Research Board DRDO Ministry of Defence India through a R&D project No.ARMREB/MAA/ 2012/142 

主　　题：AA7075-T651 aluminum alloy friction stir welding microstructure mechanical properties 

摘      要：Friction stir butt welding of AA7075-T651 plates with thicknesses of 10 and 16 mm was investigated. Defect-free, full- penetration welds were obtained after careful process parameter selection. While the nuggets in both welds exhibited very fine reerystallized grains, and finer grains were observed in welds made on 10 mm thick plates. Microhardness surveys revealed that significant loss in hardness occurs in the heat-affected zone. The reduction in hardness due to the welding process is higher in the case of welds made on 16 mm thick plates. Welds made on 10 mm thick plates exhibited superior tensile properties compared with those made on 16 mm thick plates. Fracture during tensile test occurred in the heat-affected zone in both cases. TEM images of specimens revealed that the heat-affected zone consisted of widened precipitate-free zones along grain boundaries and partial dissolution of precipitates in the grain interiors. It is concluded that defect-free single pass welds can be made on AA7075-T651 thick plates using friction stir welding and the welds made on 10 mm thick plates exhibit high joint efficiency.