Solid-state welding of nitinol shape memory alloys: A review

Nitinol shape memory alloys are widely explored and applied in various engineering applications owing to their distinctive shape memory effect and pseudoelasticity. The welding of nitinol alloys becomes inevitable for manufacturing different geometrical structures with adequate design freedom as per the application requirements. During welding process, nitinol alloys are prone to microstructural and compositional changes and may deteriorate the mechanical and other functional properties. Welding without melting the workpiece material is highly significant due to the prevention of volatilization of alloying elements. Solid-state welding processes fulfil the crucial welding requirements of nitinol alloy. This paper discusses both the similar and dissimilar welding of nitinol using solid-state welding processes in detail. The influence of welding process parameters on metallurgical and mechanical properties were discussed. In addition, the smart functional properties of welded structure and their corrosion behaviour have been discussed.