期刊
JOURNAL OF ALLOYS AND COMPOUNDS
卷 765, 期 -, 页码 1253-1262出版社
ELSEVIER SCIENCE SA
DOI: 10.1016/j.jallcom.2018.06.187
关键词
Al-Si-Mg casting alloy; Low cycle fatigue; Precipitates; Fracture morphology; Dislocation structure
资金
- National Natural Science Foundation of China [51271209]
- Foundation for Innovative Research Groups of the National Natural Science Foundation of China [51421001]
The strain-controlled low cycle fatigue (LCF) behaviour at 300 degrees C and the microstructure of Al-7Si-0.3Mg casting alloys with additions of Zr and/or Hf are studied. Microstructural characteristics are investigated in detail by optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It is found that the Zr- and/or Hf-rich primary particles and precipitates form in the alloys and have a significant effect on the fatigue properties. The cyclic softening characteristics are mainly attributed to the combination of the effects of the interaction of dislocations with nanobelt-like precipitates and an over-ageing phenomenon in the Mg2Si phase during the LCF test at 300 degrees C. The dislocations climbed over the nanobelt-like precipitates and tangled around the rectangle-like precipitates. Fatigue cracks initiated from the specimen surface, and crack propagation was characterized by dimple-like features coupled with fatigue striations. The best fatigue resistance of Al-7Si-0.3Mg-0.14Zr-0.44Hf casting alloy is related to the combination of morphological changes of the primary phase, the pinning effect of the Zr + Hf-rich precipitates and the different fracture characteristics. (C) 2018 Elsevier B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据