Formation of Nanostructured Coating Layers of Al_3Ti and its Composites by Rapidly Consolidation of Mechanically Alloyed Powders

摘要

Nano-structured thick coatings of intermetallic compound Al_3Ti and its composites were formed on Ti substrate to improve wear and oxidation properties by rapid consolidation of mechanically alloyed powders. Al, Ti and Al_2O_3 powders with compositions of stoichiometric Al_3Ti and Al_3Ti/10vol.% Al_2O_3 were mechanically alloyed (MA) for various times and their micro structural changes were investigated. The MA powders were consolidated and simultaneously bonded with Ti substrate. To retain the fine structures of MA powders, rapid consolidation process of pulsed electric current sintering (PECS) was applied. Densification behaviors of coating were evaluated quantitatively supposing that they were controlled by plastic flow of materials. Effects of MA time and Al_2O_3 particle on the microstructures and densification behavior of coatings were investigated. The obtained nano-structured coatings of Al_3Ti/Al_2O_3 composite showed more excellent wear and oxidation properties than that of monolithic Al_3Ti.