In situ diffraction study of thermal decomposition in Maxthal Ti(2)AlC

Abstract

The thermal stability of Ti(2)AlC at elevated temperature (1000–1550 °C) in vacuum has been investigated using in situ neutron diffraction. At temperatures above 1400 °C, Ti(2)AlC 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.