Investigation of Phase Composition and Microstructure of the FeAl/Al<sub>2</sub>O<sub>3</sub> Composites Fabricated by Mechanical Alloying and Plasma Active Sintering Process

Abstract

The FeAl/Al2O3 composites were fabricated by plasma active sintering process in this research. The FeAl intermetallics compounds powders were fabricated by mechanical alloying and heat treatment process. The FeAl intermetallics compounds powders and Al2O3 powders were mixed and the FeAl/Al2O3 composite powders were prepared. The FeAl/Al2O3 composites bulks were fabricated by plasma active sintering process at 1200°C for 5min under the pressure of 30MPa. The phase composition and microstructure of the FeAl/Al2O3 composites sintered bulks were investigated. The XRD patterns results showed that the Fe-Al intermetallics compounds powders were fabricated by mechanical alloying for 60h. The FeAl intermetallics compounds powders were fabricated by heat treatment at 800°C, 900°C and 1000°C. The microstructure showed that the mean particles size of the FeAl intermetallics compounds powders produced by mechanical alloying and heat treatment process was rather fine and about 4-5μm. The XRD patterns results showed that there existed the FeAl phase and Al2O3 phase in the sintered composites. The FeAl/Al2O3 composites sintered bulks exhibited the homogenous and compact microstructure. The microstructure of the FeAl/Al2O3 composites became more compact and homogenous with the increase of FeAl content. The mean particles size of FeAl was about 2-3μm and the mean particles size of Al2O3 was about 2-3μm. The density and relative density of the FeAl/Al2O3 composites increased gradually with the increase of FeAl content.