Publication

Abstract : This investigation reports the effect of thermal shock of different gradients, i.e., immediate transition from high temperature to cryogenic environment and vice versa on the flexural properties of Al2O3 particulate reinforced Cu metal matrix micro- and nano-composites fabricated by powder metallurgy route. The specimens were also thermally conditioned at high as well as sub-zero temperatures separately. The specimens were subjected to 3-point flexural test followed by fractography, and the fracture micro-characteristics were studied under field emission scanning electron microscopy and transmission electron microscopy to predict the dislocation behavior under induced thermal stresses and mismatch. The degree of improvement in flexural strength is higher for the composites experiencing lower degree of thermal shock, i.e., improvement in flexural strength is higher for a thermal shock of 80 °C than for 160 °C temperature gradients. Particle pull-out, crack entrapment, and physical outgripping of alumina particles act as the operative mechanisms during fracture of thermally shocked composites.