Effect of thermal shock and loading rate on the microstructure and properties of Cu/Al2O3 composites

Abstract

Metal matrix composites have pervasive applications in automotive and aerospace industries due to excellent properties like high strength to weight ratio which provides excellent weight saving in large components. The copper-alumina composites have high electrical and thermal conductivity coupled with good toughness of copper and hardness of alumina. Nano particulates form stronger and stiffer composites than the micron as they effectively hinder the dislocation movement prohibiting grain coarsening of copper during heat treatment. Thermal shock while in material application plays a dominant role during its performance as it triggers interfacial de-cohesion/cohesion and particle pull out which will check any amelioration or impairment of the properties. 1,3,5 vol.% nano composites and 5,10,20 vol.% micro composites were fabricated by powder metallurgy followed by conventional sintering. Mechanical property determination like micro-hardness measurements, 3-point bend testing was done for thermally shocked specimens under ex-situ and in-situ conditions, followed by characterization under scanning electron microscopy to demarcate the variation in properties. Effect of loading rate on the flexural strengths of the composites was also demonstrated