Effect of particulate reinforcing on stress corrosion cracking performance of a SiCp/2024 aluminum matrix composite

The stress corrosion cracking (SCC) performance of a. SiCp/2024 aluminum matrix composite in NaCl aqueous solution is examined by means of bolt loaded double cantilever beam (DCB) experiment as well as slow strain rate tension (SSRT) experiment Effect of the particulate reinforcing on composite's SCC performance is discussed. It is found that the composite suffers from SCC by mechanism of intergranularly anodic dissolving, just as 2024 aluminum alloy. The experiment results lead to such new conclusion that although no essential change is introduced to the SCC performance by the presence of the particulate in the composite as compared to the monotonous aluminum alloy, the composite's SCC resistance is greatly enhanced with respect of the counterpart 2024 aluminum alloy. The enhancement is attributed to: (1) the fine microstructure of the composite; (2) the strain concentration phenomenon around the reinforcing particles; (3) the hindering effect of the particles located at grain boundaries on intergranular cracking.