This seminar has been cancelled.
After an introduction to Imperial College, the Dept. of Materials and the Centre for Advanced Structural Ceramics work on Ultra high temperature ceramics (UHTC) such as ZrB2, ZrB2/SiC, HfB2/SiC and ZrC will be described. UHTCs are being developed for a number of aerospace, military and nuclear applications where resistance to extreme conditions of temperature and atmosphere is needed. This presentation will describe characterisation of the microstructures of these ceramics before and after modification by irradiating with a high power continuous wave laser to form a rapidly solidified continuous surface layer. Laser surface modification or these UHTC with a high power laser is associated with a series of processes including heating, melting, and evaporation of material. Detailed characterisation of the laser surfaces using X-ray diffraction (XRD), scanning electron microscopy (SEM), focussed ion-beam secondary mass spectrometer (FIB-SIMS) and transmission electron microscopy (TEM) was carried out to explain the development of texture, and evolution of microstructure in terms of grain size, morphology, porosity and roughness with laser heat treatment variables such as heat flux, irradiation time and cooling rate.
Host: Manish Chhowalla