Mechanical and tribological characterization nitrided Al-7075/Al2O3 metal matrix composites

Abstract

This research is mainly intended to evaluate the effect of nitriding on
the wear behaviour of Al2O3 reinforced aluminium-7075 metal matrix composite materials. The composites were prepared by using powder metallurgy process. The amount of Al2O3 in these composites was varied from 3% to 7% (by weight) in steps of 2%. Homogeneously mixed powder by using double cone mixture was compacted using hydraulic press with 60KN of load. The compaction load was optimized to get a equal density as base specimens,then the compacted specimens were sintered at 5400 C which is 80% of melting temperature aluminium base alloy. The sintered materials were nitrided with a temperature of 520°C for 72hrs. Two different set of specimens, namely, nitrided composites and non-nitrided composites specimens were tested for their wear resistance and hardness properties. Pin-on-disc equipment was used for wear testing and microhardness testing machine was used for hardness testing. Elemental X-Ray Diffraction technique (XRD) was used to ensure the diffusion of nitrogen to the surface of composites. After all the standard tests it was observed that the nitrided composites have shown better wear resistance than the non-nitrided composites