Abstract
NiTi/Stainless Steel(SS)sheets have been welded via a vacuum electron beam welding process,with three methods(offsetting electron beam to SS side without interlayer,adding Ni interlayer and adding FeNi interlayer),to promote mechanical properties of the NiTi/SS joints.The joints with different interlayers are all fractured in the weld zone near the NiTi side,which is attributed to the enrichment of intermetallic compounds including Fe2Ti and Ni3Ti.The fracture mechanisms of different joints are strongly depen-dent on the types of interlayers,and the joints without interlayer,adding Ni interlayer and adding FeNi interlayer exhibit cleavage fracture,intergranular fracture and mixed fracture composed of cleavage and tearing ridge,respectively.Compared with the brittle laves phase Fe2Ti,Ni3Ti phase can exhibit certain plasticity,block the crack propagation and change the direction of crack propagation.The composite structure of Ni3Ti and Fe2Ti will be formed when the FeNi alloy is taken as the interlayer,which provides the joint excellent mechanical properties,with rupture strength of 343 MPa.
NETL
NSTL
维普
万方数据