In situ diffraction study of thermal decomposition in Maxthal Ti2AlC.

Abstract

The thermal stability of Ti2AlC at elevated temperature (1000–1550°C) in vacuum has been investigated using in situ neutron diffraction. At temperatures above 1400°C, Ti2AlC became unstable and began to decompose via sublimation of Al, resulting in a porous surface layer of TiCx being formed. The apparent activation energy for Ti2AlC decomposition was determined to be 85.7 ± 2.6 kJ mol−1. The kinetics of isothermal phase decomposition was modelled using least-squares linear regression fitting and the Avrami equation. The corresponding least-squares regression exponent (R2) and Avrami constants (k and n) for isothermal decomposition were determined to be 0.89, 0.268 min−n and 0.1, respectively. © 2011, Elsevier Ltd.