Study of Ultimate Tensile Strength and Wear Rate of Squeeze Cast Al-Si-Cu Alloy with DOM and TOPSIS Approaches

Abstract

Aluminium alloys are widely used to produce aerospace and agricultural sector components. Squeeze casting (SQC) is a liquid forging process to enrich the mechanical characteristics of light metal alloy castings. Al-Si-Cu castings were fabricated through SQC process adopting Response Surface Methodology (RSM) following Box-Behnken experimental design. Fifteen castings were fabricated by varying input factors such as squeeze pressure, pouring temperature and dwell time. Optimal process parameter settings were predicted for the responses Ultimate Tensile Strength (UTS) and Wear rate by Desirability Optimization Methodology (DOM) and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). The details of experiments and analysis are presented. The examination of microstructure and worn-out surface of squeeze castings indicated that the refi ned grain structure due to squeeze pressure application improved UTS and Wear resistance. Confi rmatory tests were conducted for settings suggested by DOM and TOPSIS. The setting suggested by DOM resulted in greater improvement. The value of UTS and wear rate predicted with DOM were verifi ed through confi rmatory tests and the measured values are in agreement with predicted values. An optimal improvement of 99.3% and 53.75% were achieved on ultimate tensile strength and wear resistance respectively in comparison with gravity die-cast components.