Ti/TiAl_(3)叠层复合材料TIG焊接头组织与性能研究

Microstructure and Properties of TIG Welding Joint of Ti/TiAl_(3) Laminated Composites

采用钨极氩弧焊(TIG)对Ti-6Al-4V/TiAl_(3)叠层复合材料进行平板对接焊,研究了不同焊接参数对接头组织和力学性能的影响。经热轧处理的Ti-6Al-4V/TiAl_(3)叠层复合材料,可通过TIG焊实现可靠连接,避免接头脆化现象发生。板材底部的金属间化合物在焊接过程中受热辐射影响发生熔化,液态TiAl_(3)和Ti反应生成Ti_(3)Al、TiAl等,使金属间化合物周围产生Ti原子贫化区,加速了Ti原子的扩散迁移,导致接头侧面形貌分为2部分:上部为熔化再凝固的焊缝区,底部为由热辐射引起扩散连接。整体接头无明显缺陷,焊缝区为α相和针状马氏体组成的网状组织,焊接接头的抗拉强度为343 MPa,约为母材的90%,断口呈韧脆混合型断裂。

In this paper, Ti-6Al-4V/TiAl_(3)laminated composites were butt welded by tungsten argon arc welding(TIG). The effects of different welding parameters on the microstructure and mechanical properties of the joint were investigated. The hot rolled Ti-6Al-4V/TiAl_(3)laminated composites can be reliably connected by TIG welding to avoid the phenomenon of joint embrittlement. The intermetallic compound at the bottom of the plate melts under the influence of heat radiation in the welding process, and the reaction between liquid TiAl_(3)and Ti generates Ti_(3)Al, TiAl and so on, which causes the depletion zone of Ti atoms around the intermetallic compound and accelerates the diffusion migration of Ti atoms,resulting in the joint profile divided into two parts: the upper part is the weld zone of melting and solidification, and the bottom is the diffusion connection caused by thermal radiation. The overall joint has no obvious defects, and the weld zone is a network of α phase and acicular martensite.The tensile strength of the welded joint is 343 MPa, about 90% of the base metal, and the fracture is ductile brittle mixed fracture.