Role of Pore Microstructures on the Decomposition Kinetics in MAX-Phase Composites
In this paper, the role of pore microstructures on the susceptibility of MAX- phase composites to thermal dissociation at 1300-1800 °C in high vacuum has been studied using in-situ neutron diffraction. Positive activation energies were determined for the decomposition of MAX phases except for Ti3AlC...
| Main Authors: | , |
|---|---|
| Other Authors: | |
| Format: | Conference Paper |
| Published: |
Asian-Australasian Association for Composite Materials (AACM)
2012
|
| Online Access: | http://hdl.handle.net/20.500.11937/24714 |
| Summary: | In this paper, the role of pore microstructures on the susceptibility of MAX- phase composites to thermal dissociation at 1300-1800 °C in high vacuum has been studied using in-situ neutron diffraction. Positive activation energies were determined for the decomposition of MAX phases except for Ti3AlC2 where negative activation energy of 71.9 kJ mol-1 was obtained due to formation of fine pores on TiCx. An Avrami exponent (n) of < 1.0 was determined, indicative of the highly restricted diffusion of Al or Si between the channels of M6X octohedra. The pore microstructure of decomposed MAX phase has been shown to play a vital role in the kinetics of decomposition with coarse-pores facilitating the decomposition process but the fine-pores hindering it. |
|---|