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Investigation of Portevin–Le Chatelier Band Strain and Elastic Shrinkage in Al-Based Alloys Associated with Mg Contents

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Journal of Materials Science & Technology 2017年第6期33卷 580-586页

作者： Yulong Cai Suli Yang Shihua fu Di Zhang qingchuan Zhang CAS Key Laboratory of Mechanical Behavior and Design of Materials University of Science and Technology of China State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing

The Portevin–Le Chatelier（PLC） effect in Al–2.30wt%Mg, Al–4.57wt%Mg and Al–6.91wt%Mg alloys has been investigated at various applied strain rates at room temperature in this study. Three-dimensional digital image correlation（3D-DIC） technique was applied to obtaining the further insight into the spatiotemporal characteristics, in particular the influence of Mg content on deformation behaviors. Mg content has a pronounced effect on serration characteristics, including the serration type and amplitude; Mg content tends to weaken the spatial correlation of the propagative bands. Additionally, the serration amplitude linearly increases with the maximum PLC band strain; high Mg content generates a higher PLC band strain at a given serration amplitude compared with low Mg content. Mg content is found to be effective to enhance the serration amplitude, the maximum PLC band strain and also the amount of elastic shrinkage outside PLC bands.

关键词： Mg content Al–Mg alloy Portevin–Le Chatelier effect Digital image correlation Elastic shrinkage

Experimental investigation of a Portevin-Le Chatelier band in Ni–Co-based superalloys in relation toγ’precipitates at 500℃

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Journal of Materials Science & Technology 2020年第14期47卷 35-41页

作者： Yanke Liu Yulong Cai Chenggang Tian Guoliang Zhang Guoming Han Shihua fu Chuanyong Cui qingchuan Zhang CAS Key Laboratory of Mechanical Behavior and Design of Materials University of Science and Technology of ChinaHefei230027China Superalloy Division Institute of Metal ResearchChinese Academy of ScienceShenyang110016China AVIC Commercial Aircraft Engine Co. LtdShanghai201108China Hainan University Haikou570228China

The macroscopically localized deformation behaviors of Ni–Co-based superalloys with differentγ’precipitate content were investigated at 500?C and 1×10-4 s-1 via an in situ method namely,digital image correlation(DIC).The DIC results showed that the serrated flow of the stress–strain curves was accompanied by localized deformation of the *** fracture morphology was characterized mainly by transgranular fracture with numerous dimples in the lowγ’content alloy,and intergranular fracture with large fracture section in the highγ’content *** Portevin–Le Chatelier(PLC)effect occurred in the investigated Ni–Co-based ***,the localized deformation of the highγ’content alloy was more severe than that of the lowγ’content alloy,and the band width was slightly ***,for the first-time ever,a special propagation feature,namely±60?zigzag bands characterized by head-to-tail connections,was observed in the highγ’content alloy.

关键词： γ’Precipitate Ni–Co-based superalloy Dynamic strain aging Portevin–Le Chatelier effect Digital image correlation

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春丽桃在潍坊的引种表现及栽培技术要点

落叶果树 2021年第5期53卷 54-56页

作者：郑玉华刘钦芝袁海收付庆川韩霞赵婧杰潍坊市寒亭区农业技术推广中心山东潍坊261100 潍坊市农业科学院山东潍坊261071

春丽桃是山东省果树研究所选育的优质极早熟桃新品种。潍坊市寒亭区三友和花木合作社在2015年引进该品种并繁育部分苗木,2016年春季栽植。结果表明,春丽桃在潍坊表现树姿开张,早实丰产,3年生树平均株产11.8 kg,折合666.7 m^(2)产量1309.... 详细信息

春丽桃是山东省果树研究所选育的优质极早熟桃新品种。潍坊市寒亭区三友和花木合作社在2015年引进该品种并繁育部分苗木,2016年春季栽植。结果表明,春丽桃在潍坊表现树姿开张,早实丰产,3年生树平均株产11.8 kg,折合666.7 m^(2)产量1309.8 kg,4年生树株产可达27.5 kg,折合666.7 m^(2)产量3052.5 kg,5年生树株产可达29.6 kg,折合666.7 m^(2)产量3285.6 kg。平均单果重185.4 g,果面全红,可溶性固形物含量12.2%,风味甜,粘核。果实发育期65 d左右,在潍坊寒亭区6月上中旬成熟。介绍了其栽培技术要点。

关键词：春丽引种表现栽培技术

The influence of temperature on the PLC effect in Al-Mg alloy

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Science China(Technological Sciences) 2011年第6期54卷 1389-1393页

作者： fu ShiHua ZHANG qingchuan HU Qi GONG Ming CAO PengTao LIU HaoWen CAS Key Laboratory of Mechanical Behavior and Design of Materials University of Science and Technology of China Hefei 230037 China

An experimental investigation of the influence of temperature on the Portevin-Le Chatelier(PLC) effect in Al-Mg alloy is *** a certain strain rate,the PLC effect is present in the temperature range of 223-328 *** serration amplitude increases monotonically with increasing temperature,whereas the behaviors of the serration period and the critical strain with temperature include a descending branch under corresponding low temperature range and an ascending branch under corresponding high temperature *** analysis in relation with dynamic strain aging(DSA) indicates that the temperature plays an important role in the PLC effect by dictating the solubility and the diffusibility of solute *** the concentration and the diffusibility of solute atoms contribute to increasing the serration *** the descending branch temperature range,the serration period mainly depends on the preparation phase and the dominant factor of critical strain is the velocity of ***,under the ascending branch temperature range,the serration period mainly depends on the pinning phase and the dominant factor of critical strain is the applied stress required for unpinning.

关键词： Portevin-Le Chatelier effect dynamic strain aging Al-Mg alloy

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护士隐性缺勤的研究进展

职业卫生与应急救援 2024年第1期42卷 137-140页

作者：刘林峰张先庚王红艳邓青川荣娴付梦雪曹俊四川护理职业学院四川成都610100 简阳市人民医院四川简阳641400

临床护士是隐性缺勤发生率较高的人群之一。关注并采取针对性措施减少隐性缺勤的发生、发展,对提高护理质量、稳定护理队伍具有重要作用。从隐性缺勤概况,隐性缺勤的评估工具,国内外护士隐性缺勤的发生现状、护士隐性缺勤的影响因素和... 详细信息

临床护士是隐性缺勤发生率较高的人群之一。关注并采取针对性措施减少隐性缺勤的发生、发展,对提高护理质量、稳定护理队伍具有重要作用。从隐性缺勤概况,隐性缺勤的评估工具,国内外护士隐性缺勤的发生现状、护士隐性缺勤的影响因素和应对策略等方面进行了全面阐述,以期为制定针对性的措施,减少护士隐性缺勤的发生提供参考依据。

关键词：护士隐性缺勤评估工具现状影响因素预防措施综述

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自然时效对6061铝合金锯齿形屈服的影响

稀有金属材料与工程 2017年第12期46卷 3728-3732页

作者：符师桦蔡玉龙张青川伍小平中国科学技术大学中国科学院材料力学行为和设计重点实验室安徽合肥230027

对固溶处理淬火后自然时效时间不同的6061铝合金在室温下进行恒定应变率的拉伸试验,研究了自然时效对锯齿形屈服效应(Portevin-Le Chatelier,PLC)的影响。实验发现,材料强度、锯齿周期和临界应变三者在自然时效0~1 h期间均无明显变化,... 详细信息

对固溶处理淬火后自然时效时间不同的6061铝合金在室温下进行恒定应变率的拉伸试验,研究了自然时效对锯齿形屈服效应(Portevin-Le Chatelier,PLC)的影响。实验发现,材料强度、锯齿周期和临界应变三者在自然时效0~1 h期间均无明显变化,在自然时效超过1 h以后随自然时效时间延长而增大;锯齿幅值在自然时效0~2 h期间随自然时效时间延长而减小,在自然时效超过2 h后趋于稳定值。自然时效过程中,强化效果明显的β''相在自然时效时间1~2h之间开始形成并随自然时效时间线性增加。结合动态应变时效模型的分析结果与实验相符合,揭示了有强化效果的析出相对PLC效应的作用机制:具有强化效果的析出相含量增多将缩短可动位错的等待时间,使得可动位错更难被钉扎,从而导致锯齿周期和临界应变增大。分析结果还表明,该合金中溶质原子主要以体扩散方式向可动位错聚集从而实现对可动位错钉扎。

关键词： Portevin-Le Chatelier效应动态应变时效 6061铝合金自然时效

Optical Fiber Grating Sensor for Force Measurement of Anchor Cable

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Wuhan University Journal of Natural Sciences 2006年第3期11卷 662-666页

作者： JIANG Desheng fu Jinghua LIU Shengchun SUI Lingfeng fu Rong Fiber Optical Sensing Technology Research Center Wuhan University of Technology Wuhan 430070 Hubei China Hubei Jianke Structural Strengthening Corporation Limited Wuhan 430071 Hubei China Wenhua College Huazhong University of Science and Technology Wuhan 430074 Hubei China

The development of the sensor suitable for measuring large load stress to the anchor cable becomes an important task in bridge construction and maintenance. Therefore, a new type of optical fiber sensor was developed in the laboratory - optical fiber grating sensor for force measurement of anchor cable （OFBFMAC）. No similar report about this kind of sensor has been found up to now in China and other countries. This sensor is proved to be an effective way of monitoring in processes of anchor cable installation, cable cutting, cable force regulation, etc, with the accurate and repeatable measuring results. Its successful application in the tie bar cable force safety monitoring for Wuhan qingchuan bridge is a new exploration of optical fiber grating sensing technology in bridge tie bar monitoring system.

关键词： new type of optical fiber sensor anchor cable tie bar cable force health condition OFBFMAC

Influence of precipitation on the Portevin-Le Chatelier effect in Al-Mg alloys

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Theoretical & Applied Mechanics Letters 2011年第1期1卷 30-33页

作者： Qi Hu,~(a))qingchuan Zhang,~(b)) Shihua fu,Pengtao Cao,and Ming Gong CAS Key Laboratory of Mechanical Behavior and Design of Materials,University of Science and Technology of China,Hefei 230027,China CAS Key Laboratory of Mechanical Behavior and Design of Materials University of Science and Technology of China Hefei 230027 China

In the alloy with solute content higher than the limiting solubility,the solute atoms that have failed to dissolve will precipitate from the solid solution and form *** this study, the Portevin-Le Chatelier(PLC) effects in annealed 5456 and 5052 aluminum alloys with different precipitation contents have been investigated under different applied strain *** results suggest that precipitations have significant effect on the PLC effect and the more the precipitations are, the greater the influence ***,the solute diffusion is pipe diffusion in 5052 alloy with lower precipitation ***,for 5456 alloy with higher precipitation content,the diffusion is no longer the case but more complex.

关键词： aluminum alloys Portevin-Le Chatelier effect dynamic strain aging tension test

基于三维数字图像相关法的5456铝镁合金锯齿形屈服研究

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金属学报 2014年第12期50卷 1491-1497页

作者：蔡玉龙符师桦王玉辉田成刚高越程腾张青川中国科学技术大学近代力学系中国科学院材料力学行为和设计重点实验室合肥230027 中国科学院金属研究所沈阳110016

利用三维数字图像相关技术研究了常温下不同厚度5456铝镁合金板状试件在加载过程中的锯齿形屈服现象及其变形分布.统计分析锯齿跌落幅值和周期发现,2者均随应变增大而增大,且锯齿周期随厚度增大而增大,而锯齿幅值与厚度相关性较弱.在拉... 详细信息

利用三维数字图像相关技术研究了常温下不同厚度5456铝镁合金板状试件在加载过程中的锯齿形屈服现象及其变形分布.统计分析锯齿跌落幅值和周期发现,2者均随应变增大而增大,且锯齿周期随厚度增大而增大,而锯齿幅值与厚度相关性较弱.在拉伸方向应变场和离面位移场中观察到了Portevin-Le Chatelier(PLC)带,PLC带宽不随应力跌落幅值变化而变化,随试件厚度增大而增大;PLC带倾角与应力跌落幅值、试件厚度无关,约为60°.将锯齿幅值和变形信息相联系,获得了锯齿幅值与带内最大应变成正比关系这一规律.通过变形时域分析发现,PLC带引起局部拉伸方向应变突增的同时,也引起相同区域离面位移的突变.

关键词： 5456铝镁合金三维数字图像相关法锯齿屈服动态应变时效