Strain rate-induced plasticity in bcc beta-Ti alloy single crystal micropillars containing brittle omega-precipitates

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	Strain rate-induced plasticity in bcc beta-Ti alloy single crystal micropillars containing brittle omega-precipitates
	Chen, W; Huang, ZW; Cao, S; Pan, Y; Huang, MD; Hu, QM; Xu, D; Sun, QY; Xiao, L; Sun, J
刊名	MATERIALS & DESIGN
	2018-01-05
卷号	137 页码:404-413
关键词	Total-energy Calculations Wave Basis-set Rate Sensitivity Titanium-alloy Biomedical Applications Phase-transformations Mechanical-properties Tensile Deformation Grain-size Strength
ISSN号	0264-1275
英文摘要	Brittle omega-precipitates in bcc beta-Ti alloys are well known to dramatically degrade material plasticity and even trigger macroscopic premature fracture, posing an obstacle for structural applications. The embrittlementmechanism is intimately related to dislocation pile-up at the omega/beta interface that leads to stress concentration and undesirable failure. The underlying physics of improving ductility remains to be further uncovered. Herewe report a new finding in beta-Ti alloy single crystal micropillar compression that the plasticity can be substantially improved bymeans of increasing strain rate, while mechanical strength simultaneously exhibits striking "faster is stronger" fashion. The results reveal that the improvement of micropillar plasticity upon higher loading rate can be ascribed to the wider deformation band, in contrast to equivalents under quasi-static mode. The microscopic examination shows that cross slip induced by screw dislocations governs the plasticity improvement, which is further validated by crystallographic analysis and first principle energy landscape calculations. This "dynamic self-toughening" behavior advances our fundamental understanding to the plastic deformation mechanism of omega-precipitate contained bcc beta-Ti alloys. (C) 2017 Elsevier Ltd. All rights reserved.; Brittle omega-precipitates in bcc beta-Ti alloys are well known to dramatically degrade material plasticity and even trigger macroscopic premature fracture, posing an obstacle for structural applications. The embrittlementmechanism is intimately related to dislocation pile-up at the omega/beta interface that leads to stress concentration and undesirable failure. The underlying physics of improving ductility remains to be further uncovered. Herewe report a new finding in beta-Ti alloy single crystal micropillar compression that the plasticity can be substantially improved bymeans of increasing strain rate, while mechanical strength simultaneously exhibits striking "faster is stronger" fashion. The results reveal that the improvement of micropillar plasticity upon higher loading rate can be ascribed to the wider deformation band, in contrast to equivalents under quasi-static mode. The microscopic examination shows that cross slip induced by screw dislocations governs the plasticity improvement, which is further validated by crystallographic analysis and first principle energy landscape calculations. This "dynamic self-toughening" behavior advances our fundamental understanding to the plastic deformation mechanism of omega-precipitate contained bcc beta-Ti alloys. (C) 2017 Elsevier Ltd. All rights reserved.
学科主题	Materials Science, Multidisciplinary
语种	英语
资助机构	National Natural Science Foundation of China [51301127, 51321003, 51402363]; 973 Program of China [2014CB644002, 2014CB644003]; 111 Project of China [B06025]; Natural Science Basic Research Plan in Shaanxi Province of China [2014JQ6205]; Fundamental Research Funds for Central Universities of China [xjj2014126]
公开日期	2018-06-05
内容类型	期刊论文
源URL	[http://ir.imr.ac.cn/handle/321006/79592]
专题	金属研究所_中国科学院金属研究所
通讯作者	Huang, ZW (reprint author), Cent S Univ, State Key Lab Power Met, Changsha 410033, Hunan, Peoples R China.; Hu, QM (reprint author), Chinese Acad Sci, Shenyang Natl Lab Mat Sci, Inst Met Res, Shenyang 110016, Liaoning, Peoples R China.
推荐引用方式 GB/T 7714	Chen, W,Huang, ZW,Cao, S,et al. Strain rate-induced plasticity in bcc beta-Ti alloy single crystal micropillars containing brittle omega-precipitates[J]. MATERIALS & DESIGN,2018,137:404-413.
APA	Chen, W.,Huang, ZW.,Cao, S.,Pan, Y.,Huang, MD.,...&Hu, QM .(2018).Strain rate-induced plasticity in bcc beta-Ti alloy single crystal micropillars containing brittle omega-precipitates.MATERIALS & DESIGN,137,404-413.
MLA	Chen, W,et al."Strain rate-induced plasticity in bcc beta-Ti alloy single crystal micropillars containing brittle omega-precipitates".MATERIALS & DESIGN 137(2018):404-413.