Preparation And Research Of Al Matrix Composites Reinforced With In-situ Crystallized Al-based Metallic Glass

Aluminum matrix composites have a wide application in the field of aerospace and motor industry resulted from excellent physical and mechanical properties like high special strength, high elastic modulus, high corrosion resistance and high capability of conductivity. Particulate-reinforced aluminum matrix composites have received extensive interest because of relatively cheap reinforcement particles, simple fabrication technique. The difference in physical and chemical properties of ceramic particles and aluminum matrix makes weak bond between ceramic particle and aluminum. There is a large proportion of Al element in aluminum-based metallic glass. Hence, the interface between aluminum-base metallic glass particles and aluminum matrix is good. Therefore, it is valuable to research on the fabrication of aluminum matrix composites reinforced with aluminum-based metallic glass.This paper has researched the effect of mechanical milling on the morphology, size and microstructure of AlNiYLaCo powders. The microstructure of devitrified AINiYLaCo particles reinforced 2024 composites was observed. And the room-temperature compression tests and elevated temperature compression tests were conducted.The AJNiYLaCo powders with diameter smaller than 30μm are metallic glass due to rapid cooling rate. The powders will crystallize and precipitate into intermetallic compounds with size about 100nm under elevated temperature. And these powders have an obvious strengthening effect. With increasing the amount of metallic glass powders, the compressive strength of the composites is enhanced. The rule of mixture can be used to predict precisely the strength of bulks when the amount of metallic glass is little. With increasing the amount of metallic glass, the experiment data deviates the rule of mixture.Inside the AlNiYLaCo powders with diameter larger than 30μm are there variety of intermetallic compounds dispersed random. After being mechanical milled for 48, the lamellar structure was obtained. The core-layer is intermetallic compounds and out-layers are Al. With increasing the time of mechanical milling, the strength of the composites is improved. However, the powder are oxidized more seriously. Therefore, the samples will fail to work under low load. The elevated temperature strength of the composites is better than that of 2024 alloy. As elevating temperature, the strength is lower and the plasticity is better.