脉冲电流强度对TIG增材制造2219铝合金显微组织与拉伸性能的影响

Effect of Pulse Current Intensity on Microstructure and Tensile Properties of 2219 Aluminum Alloy by TIG Additive Manufacturing

利用钨极氩弧焊(TIG)增材制造技术在无脉冲、弱脉冲和强脉冲交流电下制备2219铝合金,研究了脉冲电流强度对铝合金显微组织和拉伸性能的影响。结果表明:无脉冲、弱脉冲及强脉冲TIG增材制造铝合金试样的显微组织一致,主要由基体相α(Al)与第二相θ(Al_(2)Cu)构成,堆积体中部区域均为等轴晶;相比无脉冲电流工艺,弱脉冲和强脉冲电流下制备的试样晶粒尺寸更小更均匀;无脉冲、弱脉冲及强脉冲TIG增材制造铝合金试样均表现为弱织构,最大密度仅为3.42,脉冲电流强度对晶粒取向无明显作用;经T6热处理后,相比于无脉冲电流工艺,强脉冲电流下制备的试样在扫描方向的抗拉强度降低,增材方向的抗拉强度提高,整体各向异性减轻。

The 2219 aluminum alloy was prepared by tungsten inert gas welding(TIG) additive manufacturing with non-pulse,weak pulse and strong pulse alternating currents,and the effect of pulse current intensity on the microstructure and tensile properties of the aluminum alloy was studied.The results show that the microstructures of the aluminum alloy specimens fabricated by non-pulse,weak pulse and strong pulse TIG additive manufacturing were the same,mainly consisting of matrix phase α(Al) and second phase θ(Al_2Cu),and the central region of the accumulation body was composed of equiaxed crystal.Compared with that under non-pulse current,the grain size of the specimens under weak pulse and strong pulse currents was smaller and more uniform.The aluminum alloy specimens fabricated by non-pulse,weak pulse and strong pulse TIG additive manufacturing all showed weak texture,and the maximum density was only 3.42.The pulse current intensity had no obvious effect on the grain orientation.After T6 heat treatment,compared to those under non-pulse current,the tensile strength of the specimens prepared under strong pulse current in the scanning direction decreased,while in the additive direction increased,and the overall anisotropy was reduced.