Study of Mechanical Properties and Microstructure of Aluminium Alloy Reinforced with TiB₂, by in Situ Technique

Aluminium matrix composites (AMCs) are widely being used for high performance applications such as automotive, military and aerospace because of their improved physical and mechanical properties. In this course an effort has been made to study the microstructure characterization and mechanical properties of aluminium alloy AA7175 reinforced with titanium boride (TiB₂) particles. Aluminium alloy AA7175 reinforced with various amounts (2.5, 5 and 7.5, by weight %) of TiB₂ particles was prepared by stir casting method, in which TiB₂ particles were precipitated in situ through an exothermic reaction between inorganic salts such as K₂TiF₆ (Potassium hexafluorotitanate) and KBF₄ (Potassium tetrafluoroborate). The study of dry sliding behaviour was conducted using a pin-on-disc wear testing machine on the prepared samples, as per ASTM standards and it was observed that with the increase in concentration of reinforcement the wear resistance also increased. The microstructures of the AMCs were examined by optical and scanning electron microscope. The formation of TiB₂ particles enhanced the micro-hardness and ultimate tensile strength (UTS) of the AMCs. The micro hardness of the in situ synthesized AA7175-TiB₂ composite was found to be 67.63 for 2.5 %, 73.254 for 5 % and 77.92 for 7.5 % TiB₂ reinforced composite.