Ni 脆性相的生成。此外,NiTi/Co/Ti6Al4V 和NiTi/Zr/Ti6Al4V 接头均在NiTi 边界附近出现硬度最大值,分别为543HV 和467HV,且均在NiTi 边界处发生脆性断裂,其中NiTi/Zr/Ti6Al4V 接头有着较大的抗拉强度315.9 MPa 和断裂应变1.74%。
Abstract
In order to reduce the formation of brittle intermetallic compounds in NiTi/Ti6Al4V dissimilar laser welding and improve the mechanical properties of welded joints
NiTi/Ti6Al4V laser welding was performed by adding Co and Zr interlayers respectively. The effect of Co/Zr interlayer on microstructure
phase structure and mechanical properties of welded joints was studied. The results show that the microstructure of the fusion zone in NiTi/Co/Ti6Al4V and NiTi/Zr/Ti6Al4V joints is composed of equiaxed dendrites
columnar dendrites and some macroscopic segregation zones. Co and Zr can respectively replace Ni and Ti in Ti
2
Ni brittle intermetallic compounds
whi
ch inhibits the formation of brittle phases. In addition
the maximum hardness of NiTi/Co/Ti6Al4V and NiTi/Zr/Ti6Al4V joints is near the NiTi boundary
543HV and 467HV respectively. Meanwhile
brittle fracture occurs at the NiTi boundary. The NiTi/Zr/Ti6Al4V joint has a large tensile strength of 315.9 MPa and fracture strain of 1.74%.