Investigations On Mechanical Properties Of Ti Particles Reinforced Mg Based Composites

Powder metallurgy method was used to fabricate titanium particles reinforced magnesium or AZ91 matrix composites in this research. The hardness, tensile strength, Young's modulus, compression strength and frictional wear nature of acquired composites were analyzed. 3D finite element analysis was used to simulate the stress field distributions in Ti particles reinforced composites. Besides, powder metallurgy method was also used to make Ni-Ti particles reinforced AZ91 composite.The results show that, mixed powder can be refined under ball to powder ratio 20:1, rotation speed 1000rpm, 20h ball milling in planetary ball grinder with different size steel balls. Cold isopressing and die stamping were chosen to form the composite with a pressure of 350MPa and 200MPa, respectively. While sintering at 525℃for 2.5h, the composites with reasonable microstructure and properties were obtained.The composites are brittle so that their tensile performance is not very well. The hardness was improved obviously with the highest Brinell hardness of 265HB and Vickers-hardness of 122HV. Compressive strength was test as 40 MPa. The wearing mechanism of the composites in low Ti content, fast rotational speed and under heavy loads presents fatigue wear as well as grain-abrasion and oxidation wear in other condition.The mechanical property of nickel-titanium particles reinforced AZ91 is better than the composites reinforced by Ti particles.3D finite element analysis shows that addition of the Ti particles into Mg matrix alters the stress distribution, improving the strength of the materials. Furthermore, stress concentrations occur at the interfaces between Ti particles and the matrix.