6 mm thick ZK60 and ZK60-Y alloy plates were successfully friction stir welded （FSW） at a tool rotation rate of 1200 r/min and a traverse speed of 100 mm/min. FSW resulted in the dissolution of MgZn2 particles in th...6 mm thick ZK60 and ZK60-Y alloy plates were successfully friction stir welded （FSW） at a tool rotation rate of 1200 r/min and a traverse speed of 100 mm/min. FSW resulted in the dissolution of MgZn2 particles in the ZK60 and the breakup and dispersion of W-phase （Mg3Zn3Y2） particles in the ZK60-Y alloy, thereby leading; to a decrease in the hardness of the nugget zone （NZ） for the ZK60 alloy and an increase in the hardness of the NZ for the ZK60-Y alloy, respectively. While two FSW joints exhibited similar joint efficiency （87%-89% of ultimate tensile strengths of the parent materials）, the yield strength of the FSW ZK60-Y joint was substantially higher than that of the FSW ZK60 joint. The fracture occurred in the NZ and the heat affected zone for the ZK60 and ZK60-Y joints, respectively, which were consistent with the lowest hardness distribution of the welded joints.展开更多
Friction stir welding （FSW） of Mg-Zn-Y-Zr plates with 6 mm in thickness was successfully carried out under a wide range of rotation rates of 600-1200 r/rain with a constant traverse speed of 100 mm/min. After FSW, t...Friction stir welding （FSW） of Mg-Zn-Y-Zr plates with 6 mm in thickness was successfully carried out under a wide range of rotation rates of 600-1200 r/rain with a constant traverse speed of 100 mm/min. After FSW, the coarse grains in the parent material （PM） were changed into fine equiaxed recrystallized grains at the＇nugget zone （NZ）. Furthermore, the coarse Mg-Zn-Y particles （W-phase） were broken up and dispersed homogenously into the Mg matrix. With increasing rotation rates, the size of the W-phase particles at the NZ significantly decreased, but the recrystallized grain size tended to increase. The hardness values of the NZs for all the FSW joints were higher than those of the PM, and the lowest hardness values were detected in the heat affected zone （HAZ）. The fracture occurred in the thermo-mechanical affected zone （TMAZ） on the advancing side for all the FSW joints in the tensile test, due to the incompatibility of the plastic deformation between the NZ and TMAZ caused by remarkably different orientation of grains and W-phase particles. The strength of FEW ioint reaches 90% of that of its PM展开更多
基金supported by the National Outstanding Young Scientist Foundation under Grant No. 50525103the Hundred Talents Program of Chinese Academy of Sciences
文摘6 mm thick ZK60 and ZK60-Y alloy plates were successfully friction stir welded （FSW） at a tool rotation rate of 1200 r/min and a traverse speed of 100 mm/min. FSW resulted in the dissolution of MgZn2 particles in the ZK60 and the breakup and dispersion of W-phase （Mg3Zn3Y2） particles in the ZK60-Y alloy, thereby leading; to a decrease in the hardness of the nugget zone （NZ） for the ZK60 alloy and an increase in the hardness of the NZ for the ZK60-Y alloy, respectively. While two FSW joints exhibited similar joint efficiency （87%-89% of ultimate tensile strengths of the parent materials）, the yield strength of the FSW ZK60-Y joint was substantially higher than that of the FSW ZK60 joint. The fracture occurred in the NZ and the heat affected zone for the ZK60 and ZK60-Y joints, respectively, which were consistent with the lowest hardness distribution of the welded joints.
基金supported by the the National Natural Science Foundation of China (No.51001023)
文摘Friction stir welding （FSW） of Mg-Zn-Y-Zr plates with 6 mm in thickness was successfully carried out under a wide range of rotation rates of 600-1200 r/rain with a constant traverse speed of 100 mm/min. After FSW, the coarse grains in the parent material （PM） were changed into fine equiaxed recrystallized grains at the＇nugget zone （NZ）. Furthermore, the coarse Mg-Zn-Y particles （W-phase） were broken up and dispersed homogenously into the Mg matrix. With increasing rotation rates, the size of the W-phase particles at the NZ significantly decreased, but the recrystallized grain size tended to increase. The hardness values of the NZs for all the FSW joints were higher than those of the PM, and the lowest hardness values were detected in the heat affected zone （HAZ）. The fracture occurred in the thermo-mechanical affected zone （TMAZ） on the advancing side for all the FSW joints in the tensile test, due to the incompatibility of the plastic deformation between the NZ and TMAZ caused by remarkably different orientation of grains and W-phase particles. The strength of FEW ioint reaches 90% of that of its PM
