High temperature tensile and laser thermal shock properties of ceramic particles reinforced metal matrix composites

High temperature tensile property and laser thermal shock of ceramic particles-reinforced metal matrix composites (PMMC) are studied experimentally. The stress-strain curves of PMMC at 25degreesC, 100degreesC, 200degreesC and 300degreesC were measured using HT-100 Union High Temperature Microscope. It is found that the strength of this materials sharply drops if the temperature is more than 200degreesC. However, the appearances of the failure sections are different if they are fractured at different temperaturses. For the laser thermal shock results, it is found that the initial crack occurs in the notched-tip region, wherein, the initial crack is induced by void nucleation, growth and subsequent coalescence in the matrix materials or interface separation. However, crack propagation occurs by fracture of the SiC particle and it is very different from the crack initiation mechanism. The damage threshold and complete failure threshold can be described by a plane of applied mechanical load sigma (max) with laser beam energy density E-J. The difference between high temperature tensile and thermal shock is discussed.