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高能喷丸制备具有表面梯度结构的Ti-6Al-4V合金的疲劳裂纹扩展行为 被引量:3
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作者 朱文光 马驰 +2 位作者 张聪惠 胡坤 曾祥康 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2023年第10期3003-3016,共14页
通过高能喷丸(HESP)在Ti-6Al-4V合金表面成功制备梯度结构,并研究其对疲劳裂纹扩展的影响。采用光学显微镜、扫描电子显微镜、透射电子显微镜和X射线衍射仪对HESP过程中的显微组织和残余应力演变进行表征。结果表明,材料表面形成的梯度... 通过高能喷丸(HESP)在Ti-6Al-4V合金表面成功制备梯度结构,并研究其对疲劳裂纹扩展的影响。采用光学显微镜、扫描电子显微镜、透射电子显微镜和X射线衍射仪对HESP过程中的显微组织和残余应力演变进行表征。结果表明,材料表面形成的梯度纳米结构具有220μm深度的残余压应力层。梯度纳米结构的产生能改善合金的强塑性匹配。最大残余压应力产生于次表层,且随着喷丸时间的增加逐渐增大。HESP处理有效降低裂纹扩展速率,提高疲劳裂纹扩展寿命。残余压应力可降低裂纹尖端的有效应力强度因子范围(ΔK’eff),从而产生裂纹闭合效应并延缓裂纹扩展。同时,晶粒细化引起的晶界增加、有效滑移长度减小和裂纹尖端塑性区的协同作用也会使裂纹扩展阻力增大。 展开更多
关键词 TI-6AL-4V合金 高能喷丸 表面梯度结构 裂纹扩展速率
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Dynamics of a Reaction-diffusion-ODE System in a Heterogeneous Media
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作者 cong-hui zhang Hai-feng zhang Mei-rong zhang 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2024年第2期275-301,共27页
The existence and stability of stationary solutions for a reaction-diffusion-ODE system are investigated in this paper.We first show that there exist both continuous and discontinuous stationary solutions.Then a good ... The existence and stability of stationary solutions for a reaction-diffusion-ODE system are investigated in this paper.We first show that there exist both continuous and discontinuous stationary solutions.Then a good understanding of the stability of discontinuous stationary solutions is gained under an appropriate condition.In addition,we demonstrate the influences of the diffusion coefficient on stationary solutions.The results we obtained are based on the super-/sub-solution method and the generalized mountain pass theorem.Finally,some numerical simulations are given to illustrate the theoretical results. 展开更多
关键词 reaction-diffusion-ODE system discontinuous stationary solutions stability asymptotic behavior monotone solutions
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Determination of mechanical properties of pure zirconium processed by surface severe plastic deformation through nanoindentation 被引量:3
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作者 Yao-Mian Wang Wei Zhuang +1 位作者 Huan-Ping Yang cong-hui zhang 《Rare Metals》 SCIE EI CAS CSCD 2019年第9期824-831,共8页
Commercially pure zirconium was processed by the surface mechanical attrition treatment(SMAT),and the microstructure observation showed that a gradient structure was induced.Nanoindentation measurements were taken to ... Commercially pure zirconium was processed by the surface mechanical attrition treatment(SMAT),and the microstructure observation showed that a gradient structure was induced.Nanoindentation measurements were taken to obtain the load-displacement curves at different depths below the treated surface.Using dimensional analysis,the local yield stress,hardness,strain hardening exponent,and elastic modulus at the corresponding depths were derived.The results showed that the yield stress and hardness varied with depth,while the strain hardening exponent and elastic modulus were approximately invariable.The finite element method was used to simulate nanoindentation at different depths below the treated surface to verify the derivation of the local elastic-plastic constitutive relationship.Stressstrain curves were computed for the treated samples through the rule of mixtures,and they agreed well with the experimental results.The analysis showed that the surface and subsurface hardening layers as well as the transition layer shared a high load applied to the samples,even though their volume fraction was small. 展开更多
关键词 MECHANICAL property SEVERE plastic deformation GRADIENT microstructure NANOINDENTATION FINITE element method
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