Nd对Al2O3f/AZ91D复合材料高温蠕变性能的影响

Effect of Nd on the High Temperature Creep Resistance of Al2O3f/AZ91D Composites

摘要:

利用高温压缩蠕变实验研究了Nd对复合材料的高温蠕变性能以及压应力对蠕变应力指数的影响。结果表明稀土元素Nd的加入可以明显改善复合材料的高温蠕变性能，试验中添加0.8%Nd的Al2O3f/AZ91D复合材料的抗高温蠕变性能最好；当应力为60~90 MPa与156~180 MPa时复合材料的蠕变机理为基体和增强体之间的载荷传递，纤维的开裂和破断是其失效的主要机制；应力为90~156 MPa时复合材料的蠕变机理为位错滑移与位错攀移共同作用。

关键词:Al2O3f/AZ91D复合材料;Nd; 蠕变性能;蠕变应力指数

Abstract:

The effect of Nd on high temperature creep properties of Al2O3f/AZ91D and the effect of compressive stress on creep stress exponent were analyzed. The results show that the creep resistance of Al2O3f/AZ91D composite is significantly improved by Nd addition, and Al2O3f/AZ91D with 0.8% Nd has the best creep resistance. When the stress is in the range of 60-90 MPa and 156-180 MPa, the creep mechanism is the load transfer between the matrix and the reinforcement, and the composite failure mechanism is the cracking and breaking of fibers. When the stress is in the range of 90-156 MPa, the creep mechanism is viscous glide of dislocation and climb of dislocation.

Key words:Al2O3f/AZ91D composite; Nd; creep resistance; creep stress exponent