热输入对脉冲TIG电弧增材制造Ti6Al4V钛合金微观组织与力学性能的影响  

Effect of heat input on microstructure and mechanical properties of pulsed TIG-based wire arc additive manufactured Ti6Al4V alloy

作　　者：高震 王颖 杨蔚然 杨振文 李会军 GAO Zhen;WANG Ying;YANG Weiran;YANG Zhenwen;LI Huijun(Tianjin Key Laboratory of Advanced Joining Technology,School of Materials Science and Engineering,Tianjin University,Tianjin 300350,China)

机构地区：[1]天津大学材料科学与工程学院天津市现代连接技术重点实验室,天津300350

出　　处：《中国有色金属学报》2024年第10期3366-3381,共16页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(52174369,52222511)。

摘　　要：电弧增材制造固有的高热输入导致钛合金构件中易产生粗大组织,造成力学性能的下降。为细化钛合金组织,通过在电弧增材制造Ti6Al4V钛合金过程中施加脉冲电流,研究了基值电流和占空比对增材制造Ti6Al4V钛合金凝固过程微观组织和力学性能的影响,探究热输入对电弧增材制造Ti6Al4V钛合金凝固过程、微观组织和力学性能的影响。结果表明,随着基值电流和占空比的降低,沉积Ti6Al4V合金的热输入由988 J/mm下降到414 J/mm,凝固熔池温度梯度G逐渐降低,生长速度R逐渐增大,使得粗大β柱状晶向等轴晶转变。随着热输入逐渐降低,冷却速率由7.27℃/s提高到44.08℃/s;高冷却速率促进α板条细化,α板条宽度从1.07μm减小到0.49μm。β等轴晶的形成和α板条的细化提高了沉积Ti6A14V钛合金力学性能,试样的抗拉强度由914 MPa增加到1049 MPa,塑性保持在8%。Due to the high heat input of wire arc additive manufacturing,it is easy to produce coarse microstructure in the titanium alloy,resulting in lower mechanical properties.In this study,the effects of heat input and duty cycle on the process,microstructure and mechanical properties of Ti6Al4V titanium alloy fabricated by wire arc additive manufacturing were investigated by applying plused currents during the wire arc additive manufacturing Ti6Al4V.The results indicate that,with the base current and peak time ratio decreasing,the heat input reduces from 988 J/mm to 414 J/mm.This reduction is accompanied by a decrease in the temperature gradient(G)and an increase in the solidification rate(R),which leads to the transformation of coarseβcolumnar grains into equiaxed grains.At the same time,with the decrease of the heat input,the cooling rate increases from 7.27℃/s to 44.08℃/s.The high cooling rate promotes the refinement of theαlaths,the width of theαlaths reduces from 1.07μm to 0.49μm.The formation ofβequiaxed grains and the refinement ofαlaths improve the tensile strength from 914 MPa to 1049 MPa,and the strain remains at about 8%.

关 键 词：脉冲电弧增材制造 钛合金 热输入 温度梯度 组织细化 

分 类 号：TG146.4[一般工业技术—材料科学与工程]