Processing and Characterization of NiTi Alloy Processed through Tungsten Inert Gas Welding

Abstract

This study investigates TIG welding of NiTi alloy under three different parameters, referred to as parameter 1, parameter 2, and parameter 3, while maintaining constant welding conditions. Investigations include optical micrographs, EDAX analysis, micro-Vickers hardness testing, and yield and tensile strength evaluations.The optical micrographs unveiled diverse surface topographies, including fine secondary phase distribution, equiaxed and coarse grains, as well as dendritic structures, contingent upon the solidification process. EDAX reports confirmed the presence of crucial elements, Ni and Ti, while reassuringly revealing the absence of oxide formation during welding. Notably, micro-Vickers hardness testing demonstrated significant variations in hardness values attributed to the uniform distribution of secondary phases within the matrix. The most striking observation of 40% increase in the 0.2% yield strength and a 10% enhancement in ultimate tensile strength as the welding current parameter was elevated from 50 A to 100 A. This remarkable improvement in strength can be primarily attributed to microstructural modifications across different zones and impact of welding current on mechanical properties. These findings underscore crucial role of welding parameters in shaping the microstructure and mechanical performance of NiTi alloy, providing valuable insights for optimizing TIG welding processes in various applications, from aerospace to medical device manufacturing.