EFFECTS OF HOT-ROLLING PROCESSES ON THE FRACTURE BEHAVIORS AND MECHANICAL PROPERTIES OF 2009Al/SiCp METAL MATRIX COMPOSITES

Defects such as pores and weak interfacial bonding in SiC-reinforced aluminum-matrix composites (AMCs) limit the reinforcement effect. The objective of this study is to control the microstructural defects and status of the Al/SiC interface in an 2009Al/SiCp composite using rolling processes. The influence of the rolling reduction rate on the microstructure and mechanical properties is investigated. The fracture behavior of the 2009Al/SiCp composite is observed through in-situ scanning-electron-microscopy tensile tests. The results demonstrate that an appropriate rolling reduction rate can effectively eliminate microstructural defects in the matrix and enhance the interfacial bonding strength of Al/SiC. Plastic deformation during the rolling processes expands the dislocation-strengthening regions near the Al/SiC interface. Consequently, mechanical loads can be more efficiently transferred from the aluminum matrices to SiC particles. In the as-sintered specimens, cracks primarily initiate at the Al/SiC interfaces during tensile tests. In contrast, cracks predominantly propagate from the SiC particles to Al matrices in the as-rolled specimens. This work provides a fundamental understanding of the dynamic changes in the microstructure and the resulting mechanical properties during hot rolling of SiC-reinforced AMCs.