| Mechanical Alloying (MA) prepared Al ase composite dispersedly strengthened by Al203 and SiC granules in my study. In this thesis, the microstructure and size of composite powders and dispersion state of A1203 and SIC under different milling times were examined and analysized by metal icroscope, SEM, TEM, X ay diffraction and granularity instrument. Effect of high nergy ball milling and general mixing on the spatial distribution of reinforcements of composites was investigated systematically at qualitative and quantitative level. Physical properties of composite possessing various contents of A1203 and SiC. By analyzing the kinetics of planetary ball milling, the impact behavior of milling ball is investigated, theoretical relationships between the technical parameters of ball milling (RbP: ball to powder ratio, Q angular velocity of milling, rb: radius of milling ball) and the velocity (vb), average free path (8) and impact frequency (f) of milling ball are established in this thesis. After analyzing of the collision during the process of ball milling, an angle factor is introduced, and a theoretical relationship between the physical parameters of powders (such as the deformation and the temperature rise, etc. ) and the technical parameters of ball milling and the angle factor is settled. The results showed that the composite by MA had minute size, well istributed microstructure, excellent properties, and the temperature rise didn t exceed lOOK during the process of ball milling, and the energy couldn t cumulate too. After pressing, sintering A1203/Al and S1C/6O6lAl composites, the laws between factors such as contents of A1203 and SiC, pressing pressure, sintering temperature, etc. and figuration quality, microstructure, micro igidity and relative density after sintering were studied. The causes that the dynamic properties of composite were analysized according to the microcosmic theory of dislocation.
|
PDF Full Text Request