National Natural Science Foundation of China (Grant No. 51505471) and the Self-Determined Project for Youth of State Key Laboratory of Robotics, Shenyang Institute of Automation Chinese Academy of Sciences (Grant No. Y3A1209).
In order to improve the joint performances by controlling the thermal effect of tool shoulder, a non-shoulder-plunge (NSP) welding tool is utilized to conduct friction stir welding (FSW) of an Al-Mg aluminum alloy in this paper. Sound FSW joint is successfully produced by using the NSP welding tool. In contrast to conventional FSW (C-FSW), the thermal effect of tool shoulder is effectively reduced by NSP-FSW, leading to a significant size reduction of shoulder-affected zone in the joint. Besides, the NSP-FSW joint shows finer grain structures in the stir zone and thermo-mechanically affected zone, and exhibits lower extents of grain coarsening, dislocation polygonization, and particle dissolution in the heat-affected zone. Hardness maps show that the softening region width of NSP-FSW joint is only nearly half that of C-FSW joint and the NSP-FSW joint exhibits higher hardness in the heat-affected zone than C-FSW joint. The tensile test results indicate that the joint efficiency is improved from 89 % of C-FSW joint to 97 % by the NSP-FSW process.
Zhang HJ,Wang M,Zhu Z,et al. Improving the structure-property of aluminum alloy friction stir weld by using a non-shoulder-plunge welding tool[J]. International Journal of Advanced Manufacturing Technology,2016,87(1):1095–1104.