Papers by Keyword: TiB₂/Al Composite

Abstract: 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.

Abstract: A high reinforcement content TiB2/2024Al composite with an average particle size of 8μm was fabricated by squeeze casting technology. The dynamic compression behaviors of the composite under varied strain rates were measured using split Hopkinson pressure bar, and its microstructure and fracture characteristic were examined. Resluts revealed that the composite was dense and homogenerous, and the TiB2-Al interface was clean without interfacial reactants. At high strain rate, the TiB2/Al composite showed insensitive to the strain rate, and both the flow stress and the elastic modulus improved little with an increase of the strain rate. The composite failed macroscopically in shear fracture and in split, which were caused by cracking of large reinforcement particles and interface failures under dynamic load.