The aim of this study was to evaluate microstructures and the influence of test temperature on the tensile properties, strain hardening behavior and fracture characteristics of friction stir welded （FSWed） 2219- T62...The aim of this study was to evaluate microstructures and the influence of test temperature on the tensile properties, strain hardening behavior and fracture characteristics of friction stir welded （FSWed） 2219- T62 aluminum alloy thick plate joints. A fine and equiaxed recrystallized grain structure had no significant change in grains at the top of weld nugget zone （WNZ） at a rotational rate of 500 r/min compared with 300 r/min, but the grains and second-phase particles at the middle of WNZ exhibited obvious coarsen- ing. The yield strength, ultimate tensile strength and joint efficiency were observed to decrease with increasing test temperatures. However, the elongation presented a contrast trend. Compared with the middle and bottom slices, the top slice （216 and 342 MPa） had a higher strength and a lower elongation （8.5%） at different test temperatures. Hardening capacity and strain hardening exponent of bottom slices were higher than those of the top and middle slices. Both of them at room temperature （RT） were bigger than those at higher temperature （HT） and lower temperature （LT）. The FSWed joints basically failed in the border area between the thermo-mechanical affected zone （TMAZ） and heat-affected zone （HAZ） of the top slice, and in the HAZ of the middle or bottom slices, while the fracture surfaces exhibited dimple fracture characteristics at different test temperatures.展开更多
基金the financial support of the project from the National Natural Science Foundation of China (No. 51405392)Specialized Research Fund for the Doctoral Program of Higher Education (No. 20136102120022)+1 种基金Natural Science Foundation of Shaanxi Province (No. 2013JQ6001)Fundamental Research Funds for the Central Universities (No. 3102015ZY023)
文摘The aim of this study was to evaluate microstructures and the influence of test temperature on the tensile properties, strain hardening behavior and fracture characteristics of friction stir welded （FSWed） 2219- T62 aluminum alloy thick plate joints. A fine and equiaxed recrystallized grain structure had no significant change in grains at the top of weld nugget zone （WNZ） at a rotational rate of 500 r/min compared with 300 r/min, but the grains and second-phase particles at the middle of WNZ exhibited obvious coarsen- ing. The yield strength, ultimate tensile strength and joint efficiency were observed to decrease with increasing test temperatures. However, the elongation presented a contrast trend. Compared with the middle and bottom slices, the top slice （216 and 342 MPa） had a higher strength and a lower elongation （8.5%） at different test temperatures. Hardening capacity and strain hardening exponent of bottom slices were higher than those of the top and middle slices. Both of them at room temperature （RT） were bigger than those at higher temperature （HT） and lower temperature （LT）. The FSWed joints basically failed in the border area between the thermo-mechanical affected zone （TMAZ） and heat-affected zone （HAZ） of the top slice, and in the HAZ of the middle or bottom slices, while the fracture surfaces exhibited dimple fracture characteristics at different test temperatures.
