Mechanism of In-situ Formation of AIN in Direct Nitriding Process and Characteristic of Sintered Al-AlN Composite

Sintering Phenomenon of Aluminum Alloy Powder Particle and Analysis on Particle Surface Structure (3)

Abstract

Direct nitriding process for in-situ formation of AlN has been developed by using the reaction between solid-state metallic Al and nitrogen gas after the deoxidizing reaction of the Al₂O₃ surface film by Mg contAlned in aluminum alloy powder particles. In-situ reacted AlN grows on the particle surface and has a layer structure with a width of 20-30 nm. A good bonding is observed at the interface between in-situ reacted AlN and the aluminum matrix of the primary particle. The Direct nitrided and sintered Al-AlN composite material shows superior mechanical properties, such as ultimate tensile strength and elongation, to the Al-AlN composite material produced by the conventional premixing process. This is because the hardening effect due to the fine AlN dispersions in the matrix and the good bonding at the interface between in-situ reacted AlN and the aluminum matrix.