超音波顕微鏡による金属基複合材料(MMC)の損傷評価に及ぼす影響因子の検討

抄録

Metal matrix composites (MMC) and aluminum alloy were examined by a scanning acoustic microscope (SAM) using leaky Rayleigh wave to discuss the analysis of deformation behaviour around reinforcing fibers of MMC. The plastic zone size observed was nearly equivalent to the one calculated under the plane stress codition for A6N01 aluminum alloy and the difference in Rayleigh wave velocity was about 2% between the plastic zone near a fatigue crack tip and the elastic zone. The deformation part at the tip of notch occurred preferentically in the SiC wisker poor zone for SiC_w/A7075 composite. It is suggested that fatigue cracks initiate and propagate at the whisker poor zone for this composite. The microstructure such as segregation of elements or precipitates can be analyzed by using the velocity of leaky Rayleigh waves. It is suggested that the microstructure and plastic zone may be separately identified in MMC.