Analysis on micro structure of resistance-brazed joint of TiNi shape memory alloy

Resistance brazing TiNi shape memory alloy wire with the self-improved numerical control alternating current resistance welding machine and CuNi filler foil matching the improved flux is realized.Micro-structures of resistance-brazed joint are analyzed using Optical Micro-scope,SEM and EDX measures.The results show that resistance brazing technology has less effect on the microstructure of base metal,and the joint has no obvious heat-affected zone.Ti₃Ni₄ phase compound,which is the key factor of producing double round and all round shape memory effect of TiNi shape memory alloy,is found in the joint.