Abstract: Thermal failure of SiC particulate reinforced 6061 aluminium alloy composites induced by the coupled loading with both laser thermal shocking and mechanical loading has been investigated. In the test, a pulsed Nd:glass laser beam is used with duration 1.0ms and 250(s, The notched-tip region of the specimen is subjected to laser beam rapid heating. The crack-tip process zone development and the microcracks formation are macroscopically and microscopically observed. It is found that the mechanisms for the cracks formation are different from those for the crack expansion.