IN-SITU INVESTIGATION ON THE EVOLUTION OF FAILURE PROCESSES OF A SiCp/2124AI METAL-MATRIX COMPOSITE UNDER TENSILE DEFORMATION

摘要

Using scanning electron microscope (SEM), in-situ observation was conducted on a metal-matrix composite (MMC, 20wt% SiCp/2124Al) under static tensile deformation at room temperature. The evolution of both micro-damage and macro-fracture is observed. It is found that micro-cracking dominates over the damage processes and interfacial debonding between SiC particales and Al-alloy matrix plays an important role in controlling the whole failure processes. In addition, automatic image analysis on the micrographs shows that the length of micro-cracks tends to follow a stable statistical distribution ranging from 10μm to 50μm after 1.2% strain but opening of micro-crack continues to result in an increase in the porous area of micro-cracks with stress. This damage behavior looks very similar to strain-stress curve. Some insights into the workability can be gained from the present results.