In-situ observation for the formation and propagation of cracks in YAl / Mg-Li-Al composite during dynamic tension

YAl _2P/ Mg-Li-Al composite was prepared by stir-casting. The mechanisms of the crack forming and the
propagation were investigated during the dynamic tension under the static load by SEM. The result s show that the microcracks appear at the casting defect s , in the Mg-Li-Al mat rix and on the interface of YAl _2P/ Mg-Li-Al
composite. The microcracks propagated mainly in mat rix or along the particle/ mat rix interface. The dominant crack is mainly developed along the boundary between the particle-dense regions and particle2f ree regions , and the samples lose the stability and f racture rapidly af ter the cracks propagating to some extent . The mat rix failure may play a significant role in the failure mechanism of YAl _2P/ Mg-Li-Al composite.