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A High-Ductility Mg–Zn–Ca Magnesium Alloy

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Acta Metallurgica Sinica(English Letters) 2019年第1期32卷 23-30页

作者： Teng tu xian-Hua Chen Jiao Chen Chao-Yue Zhao Fu-Sheng Pan College of Materials Science and Engineering Chongqing University National Engineering Research Center for Magnesium Alloys Chongqing University Chongqing Academy of Science and Technology

A new kind of Mg–2 Zn–0.6 Ca(wt%) alloy was fabricated by casting and hot extrusion as a high-ductility structural material. The extruded alloy exhibits a superior elongation of ～30%, yield strength of 130 MPa and ultimate tensile strength of 280 MPa along the extrusion direction at room temperature. Microstructure, texture and tensile properties of the extruded alloy were investigated in details. The remarkable improvement of ductility is ascribed to the weakened basal texture, refined grains and a small number of second phase in the alloy.

关键词： Magnesium alloy Mg–Zn–Ca High ductility Extrusion Texture

高应力炭质板岩隧道开挖支护结构受力评价研究

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科学技术与工程 2024年第4期24卷 1689-1698页

作者：胡涛涛高咸超王青松谢江胜涂鹏长安大学公路学院西安710064 中铁二十局集团有限公司西安710016 中国铁建高原隧道施工技术及装备研发中心西安710016

为探究高应力下炭质板岩隧道开挖过程中围岩位移、支护结构内力变化规律,依托渭武高速木寨岭公路隧道,采用有限差分软件FLAC3D建立三台阶七步开挖法下炭质板岩隧道的数值模型,提出强、中、弱3种支护方案;分析开挖距离对围岩位移、支护... 详细信息

为探究高应力下炭质板岩隧道开挖过程中围岩位移、支护结构内力变化规律,依托渭武高速木寨岭公路隧道,采用有限差分软件FLAC3D建立三台阶七步开挖法下炭质板岩隧道的数值模型,提出强、中、弱3种支护方案;分析开挖距离对围岩位移、支护结构内力等因素的影响,并对支护设计参数合理性评价。研究结果表明:开挖过程中围岩累计沉降和收敛变形量比较:强支护<中支护<弱支护;开挖相同距离下,随着支护强度上升,支护提供的弹性抗力越强,围岩沉降和收敛变形减小;以强支护为例,支护结构轴力呈现先增大后减小的趋势,最终轴力不断上升但趋势变缓的特征,开挖距离50 m趋于稳定;支护设计参数评价时,开挖距离(50 m)结束,强、中、弱3种方案钢架受压安全系数最小值分别为3.903、3.718、3.264,#1拱顶处强支护钢架较喷射混凝土先破坏,混凝土安全系数最小值分别为3.491、2.987、2.666,#2左拱腰处喷射混凝土较钢架先破坏,故选择中支护方案,材料I25b×C25、初衬厚度26 cm、钢架距离0.8 m。研究成果可为类似软岩隧道开挖和支护结构的设计提供一定参考。

关键词：炭质板岩围岩位移支护结构内力数值模拟合理性评价

高温临氢环境材料原位力学测试系统及其在高温合金中的应用

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分析测试学报 2024年第9期43卷 1324-1330页

作者：周万成孔帅刘利强孙彬涵张显程涂善东华东理工大学机械与动力工程学院承压系统与安全教育部重点实验室上海200237

该文设计并制造了一种高温临氢环境力学试验装置,可实现最高600℃以及2 MPa纯氢或混氢环境下材料的拉伸测试。该装置创新氢气环境箱设计,并配备真空及气体置换系统,可实现既定试验温度下高纯气体的压力控制。通过采用直线位移传感器,实... 详细信息

该文设计并制造了一种高温临氢环境力学试验装置,可实现最高600℃以及2 MPa纯氢或混氢环境下材料的拉伸测试。该装置创新氢气环境箱设计,并配备真空及气体置换系统,可实现既定试验温度下高纯气体的压力控制。通过采用直线位移传感器,实现了对材料变形量的准确稳定测量。利用该装置评价了GH4169高温合金在不同温度临氢环境下的拉伸性能,结果表明,氢环境会对材料产生明显的脆化作用,主要体现在降低材料的延伸率及断面收缩率。利用扫描电子显微技术,对GH4169在不同温度临氢环境下的断裂模式及机制进行分析发现,GH4169在200℃下的氢致损伤更为严重,主要是因为氢原子在高温下的扩散速度较快,更易在晶界上聚集并诱发氢致沿晶断裂,进而使得材料塑性显著降低。

关键词：氢损伤高温力学测试高温合金

A novel hole cold-expansion method and its effect on surface integrity of nickel-based superalloy

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Journal of Materials Science & Technology 2020年第24期59卷 129-137页

作者： xianCao Ping ZhangShuang Liu Xue-Lin Lei Run-Zi Wang xian-Cheng Zhang Shan-tung tu Key Laboratory of Pressure Systems and Safety Ministry of EducationSchool of Mechanical and Power EngineeringEast China University of Science and TechnologyShanghai 200237China

Preferred surface integrity around the hole wall is one of the key parameters to ensure the optimized performance of hole components for nickel-based *** novel hole cold expansion technique introduced in this work involves the laser texturing process(LTP)followed by the hertz contact rotary expansion process(HCREP),where the cylindrical sleeve is the critical component connecting the abovementioned two *** purpose of LTP is to obtain the most optimized strengthened cylindrical sleeve surface,preparing for the following ***,the HCREP acts on the nickel-based hole components by the rotary extruding movements of the strengthened sleeve and conical mandrel *** compared to the as-received GH4169 material,the surface integrity characterization for the strengthened hole shows that a plastic deformation layer with finer grains,higher micro-hardness,deeper compressive residual stress(CRS)distribution and lower surface roughness is formed at the hole *** addition,transmission electron microscope(TEM)observations reveal the microstructure evolution mechanism in the strengthened *** refinement near the hole wall is regarded as the fundamental reason for improving the surface integrity,where the aggregated dislocations and recombined dislocation walls can be clearly observed.

关键词： Cold expansion process Laser texturing process Surface integrity Microstructure evolution

Effect of thermal annealing on the microstructure, mechanical properties and residual stress relaxation of pure titanium after deep rolling treatment

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Journal of Materials Science & Technology 2019年第3期35卷 409-417页

作者： Jie Huang Kai-Ming Zhang Yun-Fei Jia Cheng-Cheng Zhang xian-Cheng Zhang xian-Feng Ma Shan-tung tu Key Laboratory of Pressure Systems and Safety Ministry of Education School of Mechanical and Power Engineering East China University of Science and Technology AECC Commercial Aircraft Engine Co. Ltd. Shanghai Engineering Research Center for Commercial Aircraft Engine Sino-French Institute of Nuclear Engineering and Technology SunYat-Sen University

The aim of this paper was to investigate the effect of thermal annealing on the microstructure, mechanical properties, and residual stress relaxation of deep rolled pure titanium. The microstructure and mechanical properties of the surface modified layer were analyzed by metallographic microscopy, transmission electron microscope and in-situ tensile testing. The results showed that the annealed near-surface layer with fine recrystallized grains had increased ductility but decreased strength after annealing below the recrystallization temperature, where the tensile strength was still higher than that of the substrate. After annealing at the recrystallization temperature, the recrystallized near-surface layer had smaller grain size,similar tensile strength, and higher proportional limit, comparable to those of the substrate. Moreover, the residual stress relaxation showed evidently different mechanisms at three different temperature regions:low temperature(T≤ 0.2 Tm), medium temperature(T≈(0.2–0.3) Tm), and high temperature(T≥ 0.3 Tm).Furthermore, a prediction model was proposed in terms of modification of Zener-Wert-Avrami model,which showed promise in characterizing the residual stress relaxation in commercial pure Ti during deep rolling at elevated temperature.

关键词： Deep rolling Ultra-fine grain Tensile strength Microstructure Residual stress

Effect of Stress Ratio on the Fatigue Crack Propagation Behavior of the Nickel-based GH4169 Alloy

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Acta Metallurgica Sinica(English Letters) 2017年第9期30卷 809-821页

作者： Shen Ye Jian-Guo Gong xian-Cheng Zhang Shan-tung tu Cheng-Cheng Zhang Key Laboratory of Pressure Systems and Safety Ministry of EducationSchool of Mechanical and Power EngineeringEast China University of Science and TechnologyMeilongRoad 130Xuhui DistrictShanghai 200237People'sRepublic of China AECC Commercial Aircraft Engine Co.LTD ShanghaiEngineering Research Center for Commercial Aircraft EngineShanghai 201108People's Republic of China

The fatigue crack growth behavior of the newly developed GH4169 nickel-based alloy at a maximum stress of 700 MPa and different stress ratios was investigated in the present work employing the specimens with a single micro- notch at a frequency of 129 Hz at room temperature. The results demonstrate a typical three-stage process of fatigue crack propagation processing from the microstructurally small crack （MSC） stage to the physically small crack （PSC） stage, and finally to the long crack stage. The crack growth rate in the MSC stage is relatively high, while the crack growth rate in the PSC stage is relatively low. A linear function of crack-tip reversible plastic zone size was proposed to predict the crack growth rate, indicating an adequate prediction solution.

关键词： Fatigue crack Crack growth rate Stress ratio Nickel-based alloy

Microstructures and Mechanical Properties of Mg–xAl–1Sn–0.3Mn(x=1,3,5)Alloy Sheets

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Acta Metallurgica Sinica(English Letters) 2020年第9期33卷 1217-1225页

作者： Chao-Yue Zhao xian-Hua Chen Peng Peng Teng tu Andrej Atrens Fu-Sheng Pan College of Materials Science and Engineering Chongqing UniversityChongqing 400045China Shenyang National Laboratory for Materials Science Chongqing UniversityChongqing 400045China School of Mechanical and Mining Engineering The University of QueenslandSt LuciaQLD 4072Australia

The influence of Al alloying on the microstructures and the mechanical properties of Mg–x Al–1 Sn–0.3 Mn alloy sheets was investigated. The microstructure of Mg– x Al–1 Sn–0.3 Mn consisted of α-Mg and Mg 17 Al 12 precipitates. Alloying with Al increased the amount of Mg17Al12 and the average grain size. Uniaxial tensile tests were carried out along the extrusion direction(ED), the transverse direction(TD) and 45° toward the ED. Mg–5 Al–1 Sn–0.3 Mn alloy sheet exhibited the best combination of mechanical properties along the ED: a yield strength of 142 MPa, an ultimate tensile strength of 282 MPa and an elongation of 23%. The good performance of Mg–5 Al–1 Sn–0.3 Mn sheet was mainly attributed to the large quantity of Mg17Al12 precipitates and a weak basal texture. Annealing caused static dynamic recrystallization, refined the grain size and enhanced the mechanical properties: yield strength of 186 MPa, ultimate tensile strength of 304 MPa, elongation of 21% along ED. Both strength and ductility were enhanced by Al alloying.

关键词： Mg–xAl–1Sn–0.3Mn alloys Extrusion Microstructure Mechanical properties

Genome-Wide Identification of Genes Responsive to ABA and Cold/Salt Stresses in Gossypium hirsutum by Data-Mining and Expression Pattern Analysis

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Agricultural Sciences in China 2011年第4期10卷 499-508页

作者： ZHU Long-fu he Xin YUAN Dao-jun XU Lian XU Li tu Li-li SheN Guo-xin ZHANG Hong ZHANG xian-long National Key Laboratory of Crop Genetic Improvement Huazhong Agricultural University Wuhan 430070 P.R.China Department of Biological Science Texas Tech University Lubbock 79409 USA

For making better use of nucleic acid resources of Gossypium hirsutum, a data-mining method was used to identify putative genes responsive to various abiotic stresses in G. hirsutum. Based on the compiled database including genes involved in abiotic stress response in Arabidopsis thaliana and the comprehensive analysis tool of GENEVESTIGATOR v3, 826 genes up-regulated or down-regulated significantly in roots or leaves during salt or cold treatment in Arabidopsis were identified. As compared to these 826 Arabidopsis genes annotated, 38 homologous expressed sequence tags （ESTs） from G. hirsutum were selected randomly and their expression patterns were studied using a quantitative real-time reverse transcription-polymerase chain reaction method. Among these 38 ESTs, about 55% of the genes （21 of 38） were different in response to ABA between cotton and Arabidopsis, whereas 70% of genes had similar responses to cold and salt treatments, and some of them which had not been characterized in Arabidopsis are now being investigated in gene function studies. According to these results, this approach of analyzing ESTs appears effective in large-scale identification of cotton genes involved in abiotic stress and might be adopted to determine gene functions in various biologic processes in cotton.

关键词： cold stress salt stress data-mining gene Gossypium hirsutum

Low-cycle fatigue life prediction of a polycrystalline nickel-base superalloy using crystal plasticity modelling approach

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Journal of Materials Science & Technology 2020年第3期38卷 28-38页

作者： Guang-Jian Yuan xian-Cheng Zhang Bo Chen Shan-tung tu Cheng-Cheng Zhang Key Laboratory of Pressure Systems and Safety Ministry of EducationSchool of Mechanical and Power EngineeringEast China University of Science and TechnologyShanghai 200237China The Institute for Advanced Manufacturing and Engineering Faculty of EngineeringEnvironment and ComputingCoventry UniversityCoventry CV65LZUK AECC Commercial Aircraft Engine Co.LTD Shanghai Engineering Research Center for Commercial Aircraft EngineShanghai 201108China

A crystal plasticity model is developed to predict the cyclic plasticity during the low-cycle fatigue of GH4169 *** plastic slip and energy dissipation as fatigue indicator parameters(FIPs)are used to predict fatigue crack initiation and the fatigue life until *** show that fatigue damage is most likely to initiate at triple points and grain boundaries where severe plastic slip and energy dissipation are *** predicted fatigue life until failure is within the scatter band of factor 2 when compared with experimental data for the total strain amplitudes ranging from 0.8%to 2.4%.Microscopically,the adjacent grain arrangements and their interactions account for the stress *** addition,different sets of grain orientations with the same total grain numbers of 150 were generated using the present *** show that different sets have significant influence on the distribution of stresses between each individual grain at the meso-scale,although little effect is found on the macroscopic length-scale.

关键词： Crystal plasticity Fatigue Finite element Life prediction Micro-mechanics Nickel-base superalloy