Fabrication welding and characterisation of Al LM25 SiCp metal matrix composites

Abstract

Metal matrix composites (MMCs) combine a stiff but brittle phase, typically a ceramic, with a more ductile metal matrix. The correct fractional combination of materials can result in a material with improved stiffness, creep resistance, yield stress and wear resistance relative to the monolithic matrix. Aluminium silicon alloys are one of the most commonly used foundry alloys because they offer many advantages such as good thermal conductivity, excellent castability, high strength-to-weight ratio, wear and corrosion resistance, pressure tightness and good weldability. The main objective of the present research work is to manufacture the metal matrix composites, weld using GTAW and FSW, subject it to post weld heat treatment and compare the hardness, corrosion and wear behaviors of GTA welded and FS welded LM25-SiC MMCs. Stir casting method was used to manufacture the LM25-SiC MMCs. MMCs containing 5%, 10% and 15% SiC were manufactured by stir casting process. The results revealed that the microhardness of MMCs increased with the increase in % SiC. The microhardness of cryo treated composites was higher than that of as welded composites. The study on wear behavior of welded MMCs revealed that the wear rate of composites containing 5% SiC was high and that of composites containing 15% SiC was less. The present study concludes that the FSW is more advantageous for welding MMCs compared to GTAW process. Properties of hybrid composites can also be studied and they may be characterized using XRD and EDAX. newline newline newline