Dispersion of TiC particles in an in situ aluminum matrix composite by shear plastic flow during high-ratio differential speed rolling

摘要

A combination of conventional rolling and high-ratio differential speed rolling was used to enhance the dispersion of TiC particles in the in situ aluminum matrix composite fabricated through a chemical reaction involving TiO_2, carbon and CuO powders, and the aluminum melt. An obvious improvement of the TiC particle dispersion was not achieved during conventional rolling applied up to a very large thickness reduction of 95%. The distribution of TiC, however, became reasonably homogenous after additional deformation by high-ratio differential speed rolling. The matrix grain size was also greatly reduced to 0.2 μm. The critical conditions required to obtain a uniform distribution of reinforcement in the matrix by enforced plastic flow and the possible strengthening mechanisms of the composite were discussed.