摘要
分别利用直流冷金属过渡(CMT)和变极性CMT脉冲复合技术进行TC4和ER2319焊丝的堆积,实现钛/铝异种金属丝材+电弧增材制造,通过高速摄像及电信号采集系统进行电弧形态、熔滴过渡以及电流/电压信号的采集分析;利用OM、SEM、TEM、EDS、硬度实验以及拉伸实验等方法对钛/铝异种金属构件的微观组织与力学性能进行分析。结果表明,变极性CMT脉冲复合堆积铝合金过程包括正极性脉冲阶段和负极性CMT阶段。在正极性脉冲阶段,电弧集中且热输入较大;在变极性CMT阶段,热输入较小且对构件具有明显的冷却效果。钛/铝异种金属构件的反应层包括过渡层和界面层,Ti Al3界面层的厚度约为10μm。在界面层存在微裂纹;反应层的硬度介于钛合金和铝合金之间;钛/铝异种金属构件的平均抗拉强度为65 MPa,所有拉伸试样均在界面层断裂,断裂方式均具有脆性断裂的特征。
The wire and arc additive manufactured Ti/Al dissimilar alloys can be used in the aerospace and automobile industries.For some parts,Ti alloy was replaced by Al alloy,which reduced the weight and cost.The additive manufactured Ti/Al dissimilar alloys had the advantages of two materials and remedied the each other’s shortcomings.In this study,TC4 and ER2319 wires were deposited by direct current cold metal transfer(CMT)and variable polarity-CMT+pulse mode,respectively,to realize the wire and arc additive manufacturing for Ti/Al dissimilar alloys.The arc shape,droplet transfer,voltage and current were captured by high speed camera and electrical signal acquisition system.Microstructure and mechanical properties of Ti/Al component were analyzed by OM,SEM,TEM,EDS,hardness test and tensile test.The results showed that the variable polarity-CMT+pulse welding process included the positive pulse periods and negative CMT periods.During the positive pulse periods,the arc concentrated at theend of welding wire.During the negative CMT periods,the heat input was low,which had a cooling effect on component.The reaction layer in the component included the interface layer and transition layer.The thickness of Ti Al3 interfacial layer was 10μm.The hardness of reaction layer was between that of Ti and Al alloys.The crack was formed in the interface layer.The average tensile strength was approximately65 MPa.All samples fractured in the interface layer.The fracture mode was brittle fracture.
作者
田银宝
申俊琦
胡绳荪
勾健
TIAN Yinbao;SHEN Junqi;HU Shengsun;GOU Jian(Tianjin Key Laboratory of Advanced Joining Technology,School of Materials Science and Engineering,Tianjin University,Tianjin 300354,China)
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2019年第11期1407-1416,共10页
Acta Metallurgica Sinica
基金
国家自然科学基金项目No.51575381
天津市应用基础及前沿技术研究计划项目No.15JCZDJC38600~~
关键词
钛合金
铝合金
变极性冷金属过渡脉冲复合
增材制造
Ti alloy
Al alloy
variable polarity cold metal transfer plus pulse
additive manufacturing
