Recycling of titanium as reinforcement in cast aluminium alloy A356 for improving the microstructural refinement and mechanical performance towards a sustainable material development

A356 is one of the most commonly used Al-Si cast alloy containing copper, magnesium and titanium, as other predominant alloying elements. Due to its wide application in domains where dominant loading is compressive in nature, various research work is being carried out to improve the compressive performance of A356 alloy by adding particulate reinforcement in it, converting it to metal matrix composite. However, ceramic particles added as reinforcement have always been posing challenges due to the poor wettability and weak interface bonding. In the present research work, an attempt is made to recycle titanium in a greener way of adding it to Aluminium alloy as a strengthening reinforcement which shall address the interface boding issues due to better compatibility of Titanium and Aluminum – both being metals. 5% by weight of micro and nano-sized Titanium particles is added to A356 through stir casting method. Cast material was then subjected to hot extrusion. The as-cast and extruded composites are studied for the micro structural evolution and mechanical performance against the base alloy. Results indicate that the performance of the composite is found to be significantly enhanced as compared with the base alloy in terms of strength, hardness and ductility. Increased mechanical performance is attributed to refinement of dendrite size, presence of uniformly distributed Ti particle, and partial diffusion of Ti into the Al matrix.