Investigation on Purification and Degassing of TiB₂/Al Composite Fabricated by LSM Method

In the present paper, TiB2/Al composite with 5% volume fraction of TiB2 was fabricated by LSM method. The effects of purification and degassing methods on TiB2/Al composite were examined by means of X-ray diffraction (XRD) and image analysis. Hydrogen contents in the molten composites were detected and compared among flux, inert gas and vacuum purification processes. The experimental results indicate that under general cast condition a majority of the TiB2 particles distribute on grain boundary, and only a few particles disperse within grains. The flux and vacuum purifications have no virtual impact on the distribution of TiB2 and the fraction of TiB2 remains the same after purification. However, degassing with inert gas will be detrimental; the TiB2 particles will be separated and removed from the matrix. The hydrogen contents for flux, inert gas and vacuum processes are 0.15ml/100g/Al, 0.12ml/100g/Al and 0.12ml/100g/Al respectively.