In-situ SEM observation of crack propagation along explosive clad interface

The micro-fracture mechanism of explosive clad Al/LY12 interface were studied by scanning electronic microscopy(SEM) with in-situ tensile.The results indicate that,under uni-axial tensile,the microcracks mechanism of interface at the weak site of voids and debonding is interface cracks of metal/metal,and as well as the micro-cracks grow by means of brittle mode to debond interface or dislocation emission,blunting and sharpening.And each other of main cracks and microcracks coalesces through ductile or brittle fracture of the metal ligament.On the fractured interface,both the surfaces of the interface and metal exist alternately along the crack growth path.The fracture toughness of the bimetallic interfaces is lower than those of respective counterpart metals.