YAl 2P / Mg -Li -Al复合材料动态拉伸断裂过程原位观察

通过 SEM中静载动态拉伸 , 原位观察和研究了搅拌铸造法制备的 YAl _2P/ Mg-Li-Al 基复合材料裂纹的萌生及扩展机制。结果表明 , 微裂纹萌生位置主要为复合材料的铸造缺陷处、 复合材料的基体中以及颗粒/基体界面处 , 并以在复合材料基体中萌生为主。微裂纹的扩展主要在基体和 YAl ₂颗粒/基体界面处进行。主裂纹的长大方向具有选择性 , 裂纹主要沿颗粒贫化区与颗粒富集区的交界处开裂 , 主裂纹扩展到一定程度后 , 试样全面失稳而迅速断裂。基体的断裂失效在 YAl 2P/ Mg2Li2Al复合材料拉伸断裂过程中起很大作用。

In-situ observation for the formation and propagation of cracks in YAl_(2P)/MgLiAl 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.