微观组织对Al-Si活塞合金高周疲劳性能的影响  

Effects of Microstructure on High Cycle Fatigue Behavior of Al-Si Piston Alloy

作　　者：曹思婷[1] 郭永春[1] 夏峰[1] CAO Siting;GUO Yongchun;XIA Fcng(School of Materials and Chemical Engineering, Xi＇an Technological University, Xi＇an 710021, China)

机构地区：[1]西安工业大学材料与化工学院

出　　处：《热加工工艺》2018年第6期83-87,共5页Hot Working Technology

基　　金：装备预研领域基金重点项目(61409220103);陕西省创新人才推进计划-科技创新团队项目(2017KCT-05);陕西省教育厅重点科学研究计划项目(16JS044)

摘　　要：研究了微观组织对细化工艺处理后的三种不同晶粒度的Al-Si活塞合金室温高周疲劳性能的影响。对三种合金在不同应力下的疲劳寿命进行分析。结果表明：疲劳裂纹易在粗大的硅相、铁相及AlCuNi相处萌生,主要以穿晶方式扩展,部分裂纹沿晶界扩展;细化组织结构可提高Al-Si活塞合金的室温疲劳寿命;裂纹在小尺寸α-Al、Si相及金属间化合物中扩展时裂纹曲折度高;裂纹偏转所需能量高、耗时长,所以裂纹扩展较慢。The effects of microstructure on the room temperature high cycle fatigue performance of AI-Si piston alloy after grain refining with three different grain size were studied. The fatigue life of the three kinds of alloys under different stress levels was analyzed. The results show that the fatigue cracks easily initiate at large silicon phase, iron phase or AlCuNi phase, and then mainly extend in transcrystalline manner and the part of the cracks extend along the grain boundry. The refined grain microstructure can significantly improve the room temperature fatigue life of Al-Si piston alloy. The sinuosity of the crack is high when prolonging in small size of α-Al, silicon phase and intermetallic compound, and the extension of the crack is slow because the crack deflection consumes large amounts of energy and long time.

关 键 词：铝硅合金 高周疲劳 晶粒细化 裂纹扩展 

分 类 号：TG115.5[金属学及工艺—物理冶金] TG146.2[金属学及工艺—金属学]