Fine structure and interface characteristic of α-Al2O3 in molybdenum alloy

Abstract

Molybdenum alloy reinforced with 10vol.% alumina (α-Al2O3) was prepared using the sol–gel process combined with the powder metallurgy method. The fine structure of α-Al2O3 and the interface structure of α-Al2O3/Mo are analyzed using high-resolution electron microscopy. Systematic analysis reveals that the α-Al2O3, exhibiting polyhedron shape, had a stacking fault substructure. The fine structure of α-Al2O3 grains is characterized as the orderly stacking of several amorphous and crystalline α-Al2O3 nanograins. It is observed that an interfacial bonding zone of dimension 3–5nm existed between α-Al2O3 and molybdenum grain. In the bonding zone, the atomic arrangement was similar to the structure of α-Al2O3, yet it is relatively disordered. The crystallographic orientations at the interface can be illustrated as α-Al2O3 [122]//Mo [11(—)0] and α-Al2O3 (201(—))//Mo (110).