Investigation of TIG Cladding of NiTi Wire on Substrate 304L to Study the Effect of Applied Current on Microstructure and Mechanical Properties

Abstract

NiTi wire of 1 mm diameter was deposited on austenitic stainless steel (304L) for surface property modification using the tungsten inert gas (TIG) cladding process. The study shows that the microstructure and mechanical properties of the NiTi cladding are governed by TIG process parameters, namely TIG current. The micro-hardness of the NiTi clad region has improved 4.7 times compared to the substrate material 304L. The wear resistance of the clad layer against the abrasive disc (Al2O3) shows up to 6 times improvement than the substrate material austenitic stainless steel 304L. The presence of Ti-rich (Ni,Fe)Ti, NiTiFeCr and intermetallics, responsible for high hardness and high wear resistance, has been observed in the clad surface, which have been confirmed by the XRD and EDS analysis. The optical and FESEM micrographs of the clad, intermediate and substrate metals have been analysed, and the influence of TIG current on microstructure and mechanical properties has been investigated. With the improved significant results, NiTi clad specimens can be used as a cutting and grinding tool for industrial applications.