Ti6Al4V和Al2A12的扩散连接界面组织及力学性能

采用热等静压(HIP)工艺连接Al2A12和Ti6Al4V两种不同的航空航天用材料.利用扫描电镜、能谱仪和X射线衍射仪观察连接过渡区的微观组织和组成的演化,并测试其主要的力学性能.结果表明:采用热等静压制备这两种材料的界面连接好;Ti/Al反应层界面处形成了不同的金属间化合物,例如,Al3Ti、TiAl2和TiAl;连接接头处硬度为163HV,界面连接处剪切强度达到了23MPa,比只添加镀层而无中间层的连接强度提高了约17.9%,但低于带有中间层的连接强度.由于过烧和孔隙的形成使得断裂方式是脆性断裂.由此可知,在热等静压成形过程中异种材料的元素发生了相互扩散,在扩散连接处形成了不同的金属间化合物,这些金属间化合物影响连接处的力学性能.

Microstructure and mechanical properties of Ti6Al4V and Al2A12 diffusion bonding interface

Hot isostatic pressing (HIP) was used to join two dissimilar aerospace alloys, namely Al2A12 and Ti6Al4V, for the first time.The microstructure and compositional evolutions were evaluated in the joint interface by scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction.The microhardness and shear strength tests were applied to study the mechanical properties of the joints.As a result, different intermetallic compounds (e.g., Al3Ti, TiAl2, and TiAl) form in the reaction layer of Ti/Al.The findings show that the microhardness value of the joint region is 163HV.The highest strength in the bonding zone is 23MPa, which exhibites a 17.9% improvement compared to that only with Cu coating, but is lower than the bonding strength with the interlayer.The fracture mode is brittle fracture due to overburden and void formation.The elements of dissimilar materials diffuse into each other during the HIP.Furthermore, various intermetallic compounds form at the interface, which affects the mechanical properties of the joints.