TC4/Inconel 625真空扩散连接接头微观组织及力学性能研究

Study on Microstructure and Mechanical Properties of Vacuum Diffusion Bonded Joint Between TC4 and Inconel 625 Super Alloy

采用真空扩散连接,实现了TC4-Inconel 625异种材料的连接。采用扫描电镜和电子万能拉伸试验机对接头界面微观组织和力学性能进行了研究。结果表明,当连接时间为3 min时,在连接界面生成了α+βTi片层组织,β-Ti、Ti2Ni、Ti Ni和Ti Ni3等反应产物,接头抗拉强度达到580 MPa。当连接时间增加到5 min时,在连接界面产生了相同的多层反应产物,但反应层的厚度大大增加,从3 min时的约3μm增加到约6μm,接头抗拉强度降低至440 MPa。在3和5 min连接时间下接头断口上观察到大量的解理条纹,说明接头呈脆性断裂。

By vacuum diffusion bonding, the bonding of TC4 titanium alloy to Inconel 625 super alloy was conducted at 900 ℃under the pressure of 20 MPa. The interracial microstructure characterization and mechanical properties of the welded joint of the samples were studied by SEM and monotonic tensile tests. The results show that α＋β Ti lamellar structure, β-Ti, Ti2Ni, TiNi and TiNi3 appear at the bonding interface when the welded joint is bonded for 3min,while the tensile strength of the welded joint is 580MPa. Within increasing bonding time to 5 min, the joint exhibits resembling microstructure characteristics, whereas the total thickness of the reaction layer is significantly enhanced. The thickness of the reaction layer increases from 3 μm to 6 μm, when the bonding time changes from 3 rain to 5 min. Then, the tensile strength of the welded joint decreases to 440MPa. The cleavage patterns are observed on the fracture surface of both joints bonding for 3min and 5min, which indicates that the fracture mode of the welded joints is in brittle.