TiAl合金与置氢0.5%TC4钛合金的扩散焊接工艺

Diffusion bonding process of TiAl alloy and hydrogenated 0.5%TC4 titanium alloy

对TiAl合金直接扩散焊接和使用置氢0.5%(质量分数)TC4钛合金与TiAl合金的扩散焊接开展了研究,使用了SEM,EDS,XRD和抗剪强度试验等方法分析了焊接接头的组织和性能,研究了焊接温度、连接时间和焊接压力对接头界面及力学性能的影响。结果表明,当工艺参数为1473 K/60 min/30 MPa时,TiAl合金直接扩散焊接界面孔洞完全消失,接头抗剪强度达到285 MPa;采用置氢0.5%TC4钛合金作为中间层扩散焊接TiAl合金时,当工艺参数为1123 K/30 min/15 MPa时,扩散焊接界面的孔洞消失,并有一定厚度的反应层生成,接头抗剪强度可达290 MPa,断口界面相组成主要为TiAl,Ti3 Al,TiAl 2和Ti3 Al5等脆性相;相对于TiAl合金直接扩散焊接,采用置氢0.5%TC4合金为中间层扩散焊接TiAl合金能大幅降低TiAl合金扩散焊接工艺参数。

The direct diffusion bonding of TiAl alloy and the diffusion bonding of TiAl alloy with hydrogenated 0.5%(mass fraction)TC4 titanium alloy were carried out.SEM,EDS,XRD and shear strength test were employed to investigate on microstructure and properties of bonded joints.Effects of bonding temperature,bonding time and bonding pressure on the interface and mechanical properties of bonded joints were studied.The results showed that holes at the direct diffusion bonding interface of TiAl alloy completely disappeared at bonding parameters of 1473 K,60 min,30 MPa,and shear strength of bonded joints was up to 285 MPa.When hydrogenated 0.5%TC4 titanium alloy was used as the intermediate layer in diffusion bonding of TiAl alloy at bonding parameters of 1123 K,30 min,15 MPa,holes at the diffusion bonding interface disappeared,together with a certain thickness of the reaction layer generated,and shear strength of bonded joints was up to 290 MPa.The phase composition of fracture interface was mainly composed of brittle phases,such as TiAl,Ti3 Al,TiAl 2 and Ti3 Al5.Compared with the direct diffusion bonding,the diffusion bonding parameters of TiAl alloy could be greatly reduced by using hydrogenated 0.5%TC4 alloy as intermediate layer in diffusion bonding of TiAl alloy.