Study of microstructure and mechanical properties of NiTi wire cladding on super austenitic stainless steel 904L by TIG cladding process

NiTi wire coating was preplaced on super austenitic stainless steel (904L) for enhancing the surface mechanical property. Melting of NiTi wire of 1 mm diameter formed a clad track on the 904L stainless steel substrate using the TIG cladding process. The influence of TIG current on microstructure, phase formation, micro-hardness and abrasive wear resistance characteristics of the clad surface have been investigated. The maximum average micro-hardness of the NiTi clad layer was 952HV at current of 40 A which is 5.95 times greater than the substrate material 904L. The EDS and XRD study of the NiTi coating layer confirmed the formation of NiTi, NiTi2, and B2 (NiTiFeCr) structure as major constituent phases and some intermetallic (Cr-Fe-Ni) which improved the mechanical properties of the clad layer. The pin on disc type sliding abrasive wear of the NiTi clad layer showed the improvement of wear resistance up to 8.83 times compared to the substrate 904L.