Reversible a to b transformation in a textured Sm-sialon ceramic

Authors

Andrew CarmanFollow
E V. Pereloma, University of WollongongFollow
Y-B Cheng

RIS ID

37575

Publication Details

Carman, A., Pereloma, E. and Cheng, Y. (2011). Reversible α′ → β′ transformation in a textured Sm-sialon ceramic. Journal of the European Ceramic Society, 31 (6), 1165-1175.

Abstract

A preferential orientation was observed in a Sm-sialon ceramic, of the composition Sm_0.4Si_9.6Al_2.4O_1.2N_14.8, after hot pressing at 1800 °C for 2 h. Post-sintering heat treatment was performed at 1450 °C for 384 h, resulting in the forward α′ → β′ transformation, accompanied by the formation of M^′SS and an increase in the 21R phase. Subsequent heat treatment at 1800 °C for 2 h resulted in the reverse β′ → α′ transformation, with a corresponding decrease in the M^′SS and 21R phases. This confirms the fully reversible reaction of α′+liquid ↔ β′+M'_ss+21R in Sm-sialon ceramics. In addition, the texture introduced by hot pressing was maintained after all heat treatments, indicating that there is a crystallographic relationship between the transformation phases. The microstructure and mechanical properties were also found to be mostly reversible, contrary to the behaviour of the α′ lattice parameters and bulk density.