材料科学
开裂
机制(生物学)
低周疲劳
疲劳开裂
疲劳试验
冶金
复合材料
物理
量子力学
作者
Chengqi Sun,Han Wu,Weiqian Chi,Wenjing Wang,Guangping Zhang
标识
DOI:10.1016/j.ijfatigue.2022.107331
摘要
• Nanograins appear in a locally high-stress region during very high cycle fatigue. • Deformation twins are observed in α grains under very high cycle fatigue loading. • Twinning is a main contributor to nanograin formation for TC17 alloy. • Local nanograin formation promotes crack initiation and early growth. • A new mechanism is proposed for crack initiation and early growth in Ti alloys. This paper shows that nanograins appear in a locally high-stress region for very high cycle fatigue of TC17 alloy, and twinning is a main contributor to nanograin formation. The locally high stress results in twinning or slip in preferentially oriented α grains. Then, the interaction between twin systems or dislocations induces the formation of dislocation cells or walls, nucleation of microbands, and finally the nanograins. As a result, the nanograin regions and the boundaries between the nanograin and coarse grain regions become preferential sites for crack initiation and early growth. The finite element analysis demonstrates the nanograin-related fatigue cracking behavior.
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