YU Weicheng YUAN Jincai WANG Zhongguang Laboratory of Fatigue and Fracture for Materials
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Institute of Metal Research
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Academia Sinica
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Shenyang
,
China.
金属学报(英文版)
The fatigue of SiC_p/6061Al composite containing 15 v.-% SiC particles has been compared with 6061Al alloy.Dislocation structure and microprocess of fatigue crack initiation and propagation in the composite have been investigated by using SEM and TEM.The results in- dicate that the fatigue strength at 10~7 cycles of the composite is 196 MPa,i.e.about 25% higher than matrix alloy.The voids and microcracks initiated at and near the interface be- tween SiC_p and matrix,where has a higher density of dislocations,will propagate and link up to form the fatigue crack.It is an important evidence to note that the dislocation channels where screw dislocation can travel are formed near interface and corner region of SiC_o in the composite subjected to fatigue stress(σ_(max)=274 MPa N=2.4×10~5 cycles),demonstrating the relationship between fatigue crack initiation and dislocation movement in the SiC particles reinforced 6061 Al alloy composite.
关键词:
Al-base composite
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null
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于维成
,
袁金才
,
王中光
金属学报
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。
关键词:
Al基复合材料
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fatigue
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SiC particle
