Regensburg 2013 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 33: Structural Materials

MM 33.4: Talk

Wednesday, March 13, 2013, 11:00–11:15, H26

Study of the phase transformation in SiC/AlN ceramic composite — •Naeem-Ur-Rehman Minhas¹, Jianye Wang², Finn Giuliani², Luc Vandeperre², and Talaat Al-Kassab¹ — ¹Physical Sciences and Engineering Division, King Abdullah University of Science & Technology, 4700, Thuwal, 23955-6900, Saudi Arabia — ²Centre for Advanced Structural Ceramics, Department of Materials, Imperial College London, South Kensington Campus, London SW7 2AZ, UK

Silicon carbide (SiC) is used in various high temperature applications for its high hardness. However, the hardness of SiC drops with temperature because thermal activation of dislocations allows them to overcome the lattice resistance. Hence to enhance the high temperature properties of silicon carbide other strengthening mechanisms are needed. A tentative phase diagram of silicon carbide and aluminium nitride (AlN) points towards a region where perhaps decomposition occurs. Such phase separation should strengthen the resistance to dislocation glide or creep of SiC. The first aim is to produce a solid solution of SiC and AlN, and this will be followed by a heat treatment to induce the phase separation. X-ray diffraction results show the formation of a single phase with a simple hexagonal crystal structure confirming the formation of a solid solution. The decomposition path of the as prepared material as investigated with x-ray diffraction and transmission electron microscopy and Atom Probe Tomography will be presented and discussed within this contribution.