Microstructure and densification of gas atomised Fe-Cr-B based alloy powder consolidated by spark plasma sintering

This paper is a study of microstructure and densification of a gas atomised Fe-45Cr-5.9B-2Si-0.1C (wt-%) alloy powder consolidated using the spark plasma sintering (SPS) process. The results showed that the fabricated alloy contained about 65 wt-%(Cr, Fe)(2)B plates and 1 wt%(Cr,Fe)(7)C-3 precipitates dispersed in a 34 wt-% body centred cubic Fe based solid solution matrix containing Cr and Si. The powder was fully densified with solid state sintering for a short period of time (<10 min). After sintering, the phases did not transform, and the fraction, shape and aspect ratio of (Cr, Fe)(2)B did not change. In addition, we adapted the known SPS constitutive densification model from Olevsky and Froyen to include a microstructure factor describing deformation of a metal matrix composite powder. The model was in reasonable agreement with the experimental results.