本文测定了用15v.-％SiC颗粒(10和2.5μm)增强的Al基复合材料的疲劳强度,并用SEM和TEM研究了疲劳裂纹形成及扩展与位错结构的相互联系,结果表明:两种尺寸SiC颗粒的复合材料在10~7循环寿命下的疲劳强度都是196MPa,比基体合金提高了25％,低于10~7循环周次寿命时含粗颗粒复合材料疲劳性能优于含细颗粒复合材料。SEM观察到疲劳微裂纹及微孔洞通常在SiC_P与基体界面附近形成,并在疲劳过程中相互连接成疲劳裂纹;TEM观察到界面处特别是SiC_P尖角处存在高密度位错,足够的疲劳循环周次后该处出现位错通道。
The fatigue properties of the composite of 6061Al reinforced by 15v.-%SiC particles sized to 10--2.5μm have been examined in comparison with 6061Al.The microprocess of fatigue crack initiation and propagation as well as dislocationstructure have also been studied using SEM and TEM. For the composites reinforcedby SiC particles of two different sizes, the fatigue strength of both at 10~7 cycles is196 MPa, i.e. 25% greater than that of matrix alloy. If cycling life below 10~7, thefatigue strength of composite reinforced by coarse SiC particles is better than thatby fine particles. The voids and microcracks initiated at and near the interface be-tween SiC_p and matrix, where the higher density dislocations are presented, will pro-pagate and link up to form the fatigue crack. It is an important evidence to notethat the dislocation channels where screw dislocation can travel are formed near inter-face and corner region of SiC_p in the composite subjected to fatigue stress, demon-strating the relationship between fatigue crack initiation and dislocation movementin the SiC particles reinforced 6061Al composite.
参考文献
| [1] | |
| [2] | |
| [3] |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%