(1. 寶雞文理學院 機械工程學院，寶雞 721013；
2. 貴州大學 材料與冶金學院，貴陽 550025)
摘 要: 基于斷口學理論、借助SEM分析技術，分析高強韌Ti-55531合金片層和雙態(tài)組織在不同應力幅下的高周疲勞斷口形貌特征，揭示應力幅和組織因素對該合金高周疲勞裂紋萌生的協(xié)同作用機制，闡明組織因素對合金疲勞裂紋擴展的影響規(guī)律。結果顯示：應力幅大小對片層組織的疲勞裂紋萌生行為有顯著影響，但對雙態(tài)組織影響較小。在疲勞裂紋擴展前期，片層的裂紋擴展速率大于雙態(tài)的；但在裂紋擴展中后期，雙態(tài)的裂紋擴展速率反而更高。
關鍵字: Ti-55531合金；高周疲勞；疲勞裂紋萌生；疲勞裂紋擴展；斷口形貌
（1. Department of Mechanical and Electrical Engineering, Baoji University of Arts and Sciences, Baoji 721004, China;
2. College of Materials and Metallurgy, Guizhou University, Guiyang 550025, China）
Abstract:The high cycle fatigue(HCF) fracture morphological properties of high strength and toughness Ti-55531 alloy with LM and BM under different stress amplitude were analyzed by SEM based on the base fractography theory, the comprehensive influential mechanism of stress amplitude and microstructure factors on fatigue crack initiation were revealed, and the rule that microstructures affecting the fatigue crack propagation were illuminated. The results indicate that stress amplitude greatly affects the HCF primary crack initiation site of LM, while has a little effect on BM. The fatigue crack growth rate of LM is larger than that of BM during the crack propagation region with low speed. However, the crack growth rate of LM is lower than that of BM during crack propagation regions with high speed.
Key words: Ti-55531 alloy; high cycle fatigue; fatigue crack initiation; fatigue crack propagation; fracture morphology
