Optimizing Fatigue Life of Micro Plasma Arc Welded Titanium (Ti-6Al-4V) Alloy using Grey Relational Analysis

Abstract

Titanium (Ti-6Al-4V) is widely used in aerospace industry and preparation of medical prostheses. There is a need to study the fatigue properties as they are subjected to repeated loading in service. In the present work, Micro Plasma Arc Welding (MPAW) is used to joint Titanium (Ti-6Al-4V) alloy sheets. Peak current, base current, pulse rate and pulse width are considered as important welding parameters and fatigue life is considered as output response. In the present work Low cycle fatigue test is done under Tension-Tension mode. Sinusoidal loading is applied varying from 0.6 KN to 6 KN and keeping stress ratio at 0.1. Taguchi L25 orthogonal matrix is adopted by considering four factors and five levels of weld input parameters. Analysis of Variance (ANOVA) is carried out at 95% confidence level. Grey Relational Analysis is carried out by maximizing fatigue life to find the optimal
combination of weld input parameters. The order of importance of weld input parameters are also identified.