Wear behavior of Al-Si alloy based metal matrix composite reinforced with TiB₂

Al-Si alloy based composites are widely used in automotive, aerospace and for structural application due to improved strength to weight ratio, low density, and better wear resistance. In the present work, Al-xSi-5TiB₂ (x=7, 11, 12.6) in-situ composite was synthesized successfully by stir casting method. Here the composites were prepared by the exothermic reaction of K2TiF₆ and KBF₄ salts with the molten Al-x Si alloy. The dry sliding wear behavior of Al-Si matrix composites reinforced with 5 % TiB₂ was studied using a pin-on-disc wear testing machine to study the effect of % Si, load (10, 20, 30 N), sliding speed (1.36, 1.82, 2.27 m.s^-1) and sliding distance on stir cast Al–xSi-5TiB₂ composites. The Al-Si alloy and the reinforcement mixers were confirmed by the X-ray Diffraction analysis. The microstructure of Al-xSi-5TiB₂ composite was investigated by using Optical Microscope to determine the phases present in the prepared composites. The prepared AMC composites were tested for hardness using Vickers Hardness tester with the variation of Si. Wear rate (mm³/m), Wear resistance (m/mm³), Specific Wear rate (m³/N.m) and were analyzed with various conditions. The worn surfaces of the specimens were analyzed before and after wear testing by Scanning Electron Microscope (SEM) to determine the governing wear mechanisms in the composites. Wear rate and specific wear rate decreases at all the operating condition with increase in wt% Si. Wear resistance all most increases with increase in wt% Si. Hardness values are increased with increase in amount of Si. (paper)