Optimization of Ultrasonic-Assisted TIG (UA-TIG) Welding Process Parameters for AA7075 Alloy Joints Using RSM-GA Approach

Abstract

Abstract The current study investigates the optimized process parameters for low hot cracking susceptibility and the enhanced microhardness of ultrasonic-assisted tungsten inert gas (UA-TIG) welded AA7075 joints. The optimization trials were made using response surface methodology (RSM) and RSM coupled with genetic algorithm (RSM-GA) approaches. Welding process parameters, such as welding current, gas flow rate, presence and absence of ultrasonic vibration (UT), and filler metal were varied to study the hot crack sensitivity and microhardness of the AA7075 welded joints. RSM was used to develop the empirical relationships with a higher coefficient of determination (R2 = .9892 for hot cracking sensitivity and R2 = .9919 for microhardness). Welding current (120 A), gas flow rate (13 L/min) with UT and filler material with hot cracking sensitivity (0 %), and microhardness (117.76 HV) are the optimized process parameters. The experimental results and predicted RSM model at optimal conditions were compared to the predicted RSM-GA model for minimal hot cracking sensitivity and maximum microhardness. A good agreement between the experimental results and the predicted RSM model confirms the soundness of the developed RSM-GA model.