摘要
利用六轴机器人夹持氩弧焊枪对AZ31B变形镁合金进行了平板对焊,探讨了焊后热处理对焊接接头微观组织、第二相及力学性能的影响规律。结果表明,焊后热处理有效改善了焊接接头的微观组织,大幅提升了焊接接头的力学性能。焊后热处理后,焊接接头微观组织中晶粒尺寸没有太大改变,但沿晶界分布的第二相数量明显减少,焊接接头的抗拉强度和伸长率分别达到了母材的97.8%和84.5%。未经热处理的拉伸样品是在焊缝处断裂,断口呈现出典型脆性断裂特征;而热处理之后的拉伸则是在热影响区断裂,断口呈现出准解理偏韧性的混合断裂特征。
The auto-TIG butt welding on the AZ31 magnesium alloy was performed by the six-axis robot in the present work. After post-welded heat treated （PWHT）, the microstructure, second phase and mechanical properties of the AZ31B joints was investigated by using the optical microscope, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. The results show that after PWHT, the microstructure and mechanical properties of the AZ31B joints are both significantly improved. After PWHT, the grains of the AZ31B joints are still fine, whereas the number of the precipitates along with the grain boundaries is dramatically decreased. The ultimate tensile strength and elongation of the PWHT AZ31B joints are up to 97.8% and 84.5% of the base allay, respectively. The fracture surface of the untreated tensile specimen is brittle fracture, whereas the PWHT tensile specimen exhibit obvious ductile-brittle mixed facture, which is characterized by more dimples and small cleavage surfaces.
出处
《铸造技术》
CAS
2018年第1期120-123,136,共5页
Foundry Technology
基金
国家重点研发计划(2016YFB0301105)资助项目
山东省重点研发计划(2016ZDJS02A09)资助项目
山东省科学院青年基金(2016QN015)资助项目
