A Study on Surface Modification of Lm6Al2O3 Metal Matrix Composites

There is an ever growing demand for better materials in the aerospace and automobile industries. Conventional materials like steel and other ferrous alloys possess great strength, however they are heavy and energy inefficient. Aluminium and aluminium composites are light weight and a corrosion resistant material, it has lower specific weight and higher strength to weight ratio. The objective of this work is to propose an alternative material that will replace the traditional materials without compromising on the strength and durability. LM6 is used as the base and Al2O3 is chosen as the reinforcement. Samples were fabricated using powder metallurgy; compacted at the load of 15 ton and sintered at 550 ℃ for 60 min. The surface was also modified by gas nitriding at 450 ℃ up to 7 h. Tests for density, hardness, mechanical and wear characteristics are performed to study and evaluate structure and properties. The density of the composite was found to be lower than that of LM6. Values of hardness, tensile, compressive and shear strength showed a significant increase and further improvements were observed upon nitriding. Optimum nitriding time was found to be 4 h. The wear rate of nitrided samples was found to be lesser than LM6.