Effect of stress ratio on very high cycle fatigue properties of Ti-10V-2Fe-3Al alloy with duplex microstructure
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2018年第7期
论文作者：Ying Wu Jianrong Liu Hao Wang Shaoxuan Guan Rui Yang Hongfu Xiang
文章页码：1189 - 1195
摘 要：In fatigue critical applications, Ti-10 V-2 Fe-3 Al alloy components are expected to endure cyclic loading with cycles above 109. To assess their operating safety, S-N relations of Ti-10 V-2 Fe-3 Al alloy in very high cycle fatigue（VHCF） regime are of concern and have been investigated in this work. Fatigue behavior including S-N curves and crack initiation mechanisms is reported. Two transitions of fatigue crack initiation mechanism, from internal crack initiation to surface crack initiation and from αp cleavage to αs/βdecohesion, occur when the stress ratio（R） and stress level are reduced. Fatigue limits exist at Nf = 6 × 107 cycles for all stress ratios except for 0.5. In the VHCF regime two kinds of internal crack initiation mechanisms exist, i.e., coalescence of cluster of αp facets and αs/β decohesion. Their mutual competition depends on the stress ratio and can be interpreted in terms of different stress character required for promotion on different internal crack initiation mechanism. Small crack propagation is discussed to be life controlling process under the stress ratio range from-0.5 to 0.1 during VHCF regime while under the stress ratio 0.5 VHCF, life almost refers to the life required for crack initiation.
Ying Wu1，Jianrong Liu1，Hao Wang1，Shaoxuan Guan1，Rui Yang1，Hongfu Xiang2
1. Institute of Metal Research, Chinese Academy of Sciences2. National Demonstration Center for Experimental Materials Science and Engineering Education, Jiangsu University of Science and Technology
摘 要：In fatigue critical applications, Ti-10 V-2 Fe-3 Al alloy components are expected to endure cyclic loading with cycles above 109. To assess their operating safety, S-N relations of Ti-10 V-2 Fe-3 Al alloy in very high cycle fatigue（VHCF） regime are of concern and have been investigated in this work. Fatigue behavior including S-N curves and crack initiation mechanisms is reported. Two transitions of fatigue crack initiation mechanism, from internal crack initiation to surface crack initiation and from αp cleavage to αs/βdecohesion, occur when the stress ratio（R） and stress level are reduced. Fatigue limits exist at Nf = 6 × 107 cycles for all stress ratios except for 0.5. In the VHCF regime two kinds of internal crack initiation mechanisms exist, i.e., coalescence of cluster of αp facets and αs/β decohesion. Their mutual competition depends on the stress ratio and can be interpreted in terms of different stress character required for promotion on different internal crack initiation mechanism. Small crack propagation is discussed to be life controlling process under the stress ratio range from-0.5 to 0.1 during VHCF regime while under the stress ratio 0.5 VHCF, life almost refers to the life required for crack initiation.
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