Multi-objective optimisation of friction welding parameters in joining titanium alloy and stainless steel with a novel interlayer geometry

The main purpose of the present research work was to identify and investigate a novel method of holding the intermediate metal and to evaluate the metallurgical and mechanical properties of dissimilar Ti-6Al-4V and 304L stainless steel with copper as an interlayer material.. The study shows that the input parameters and surface geometry played a very significant role in producing a good quality joint with minimum heat- affected zone and metal loss. Based on the literature and experiments conducted in this investigation, sound weld was achieved between Ti-6Al-4V and SS304L, by using copper rod as an intermediate metal. In the present study, Ti-6Al-4V alloy and SS304L were joined by a novel method of holding the interlayer and new surface geometry for the interlayer. A minimum number of experiments required to perform the experimentation were decided to use Taguchi orthogonal array. The fabricated weld joint was analysed for quality initially by drop test and subsequently using non-destructive techniques like radiography and cross section scan (C-scan). Multi objective optimisation using grey relational analysis was done to understand the levels of process parameters at which the performance of the joint is better. Further, optical micrograph was done to substantiate the results of hardness and tensile strength.