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Analysis of local crystallographic orientation in an annealed Ti60 billet
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作者 Z.B.Zhao Z.Liu +2 位作者 Q.J.Wang J.R.Liu R.Yang 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第4期591-595,共5页
A heterogeneous microstructure in terms of local orientation distribution is often found in near-α titanium alloys. The presence of large regions with similar crystallographic orientation, called ‘macrozones’,could... A heterogeneous microstructure in terms of local orientation distribution is often found in near-α titanium alloys. The presence of large regions with similar crystallographic orientation, called ‘macrozones’,could drastically decrease the fatigue performance of titanium alloys. The present work reports on the crystallographic orientation of a near-α titanium alloy, Ti60, billet after annealing in an α+β phase field.The texture was found to be weak, and no obvious macrozone was found in our measured zone where the variant selection is suppressed. Meanwhile, in-depth electron backscattered diffraction(EBSD) analysis was applied to evaluate the final microstructure, and the mechanisms by which they formed were analyzed. 展开更多
关键词 TITANIUM ALLOYS Microstructure TEXTURE Heat treatment EBSD
Distinct dendritic α phase emerging on the surface of primary α phase in a compressed near-α titanium alloy
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作者 Z. Liu Z.B. Zhao +2 位作者 J.R. Liu Q.J. Wang R. Yang 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2018年第4期666-669,共4页
主要阶段的表面形态学的特征被学习在一近使变形了 -- 钛合金。当合金是空气冷却的在时,树枝状的阶段出现在主要阶段的表面上 ?+ 吗?在变丑以后分阶段执行领域。树枝状的谷物与它的原来的主要谷物有一样的取向。树枝状的阶段的形成能... 主要阶段的表面形态学的特征被学习在一近使变形了 -- 钛合金。当合金是空气冷却的在时,树枝状的阶段出现在主要阶段的表面上 ?+ 吗?在变丑以后分阶段执行领域。树枝状的谷物与它的原来的主要谷物有一样的取向。树枝状的阶段的形成能被接口不稳定性在主要阶段的取向附生的生长过程解释。变丑导致的脱臼能便于导致树枝状的阶段和随紧张的增加明显的更多的树枝状的阶段的形成。树枝状的阶段的生长被第二个阶段的成核最后与冷却限制。 展开更多
关键词 表面形态学 Α钛合金 树枝状 压缩 空气冷却 生长过程 不稳定性 形成能
Evolution of microstructure and phase composition of Ti-3Al-5Mo-4.5V alloy with varied β phase stability
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作者 Q.Xue Y.J.Ma +2 位作者 J.F.Lei R.Yang C.Wang 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2018年第12期2325-2330,共6页
The microstructure evolution and phase composition of an α+β titanium alloy, Ti-3Al-5Mo-4.5V(wt.%),have been investigated. Electron probe micro analysis(EPMA) quantitative results manifest that the stability of β p... The microstructure evolution and phase composition of an α+β titanium alloy, Ti-3Al-5Mo-4.5V(wt.%),have been investigated. Electron probe micro analysis(EPMA) quantitative results manifest that the stability of β phase decreases with increasing quenching temperature, which is influenced by the significant variation of β-stabilizing elements concentration. Detailed microstructure analysis shows that the β→ωphase transformation does occur when quenching at 750℃ and 800 ℃. The ω-reflections change from incommensurate ω-spots(750 ℃) to ideal ω-spots(800 ℃) as the β stability of the alloy decreases. Further the decrease of β phase stability encourages the formation of athermal α " martensite, which has the following orientation relationships: [111]β//[110]α",[100]p//[100]α " and [-110]p//[00-1]α" with respect to the β matrix. 展开更多
关键词 DUAL-PHASE titanium ALLOY β PHASE STABILITY ω PHASE α"martensite MICROSTRUCTURE
Mechanical properties and deformation mechanisms of Ti-3Al-5Mo-4.5 V alloy with varied β phase stability
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作者 Q.Xue Y.J.Ma +2 位作者 J.F.Lei R.Yang C.Wang 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2018年第12期2507-2514,共8页
Evolution of deformation mechanisms and mechanical properties of Ti-3Al-5Mo-4.5V alloy with different β phase stability have been systematically investigated. β phase stability alteration is achieved through quenchi... Evolution of deformation mechanisms and mechanical properties of Ti-3Al-5Mo-4.5V alloy with different β phase stability have been systematically investigated. β phase stability alteration is achieved through quenching temperature variation from dual α+β field(700℃) to single β field(880℃). Tensile tests at ambient temperature show that apparent yield strength of the alloy experiences an abrupt decrease followed by a significant increase from 700℃ to 880℃. Work hardening behavior is characterized by transition from the initial two-regime feature to the three-stage outlook. Concurrently, the maximum working hardening rate drops from 14000 MPa to 3000 MPa, which is concurrent with the shrinking volume fraction of primary a phase. Detailed discussion about the relationship between deformation mechanisms and β phase stability has been outlined. 展开更多
关键词 DUAL-PHASE titanium ALLOY β phase STABILITY Work HARDENING behavior DEFORMATION mechanisms
Effect of Base Material on Microstructure and Texture Evolution of a Ti–6Al–4V Electron-Beam Welded Joint
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作者 G.Q.Wang Z.B.Zhao +5 位作者 B.B.Yu J.R.Liu Q.J.Wang J.H.Zhang R.Yang J.W.Li 《金属学报:英文版》 SCIE EI CAS CSCD 2017年第5期499-504,共6页
The effect of base material(BM) on microstructure and crystallographic orientation evolution of a Ti–6Al–4V electron-beam welded joint was investigated. Meanwhile, the crystallographic orientation of prior b grains ... The effect of base material(BM) on microstructure and crystallographic orientation evolution of a Ti–6Al–4V electron-beam welded joint was investigated. Meanwhile, the crystallographic orientation of prior b grains was studied by advanced electron backscattered diffraction data processing. The inhomogeneity of microstructure within welded joint was formed due to the different microstructures of BM. By comparing microstructure details of the welded joint, including microstructure morphology and crystallographic orientation with those of the base material, it can be found that both the microstructure morphology and crystallographic orientation of the EBW joint would be controlled by BM. 展开更多
Molecular Dynamics Simulation of Tensile Deformation and Fracture of γ-TiAl with and without Surface Defects
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作者 H.N.Wu D.S.Xu +1 位作者 H.Wang R.Yang 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2016年第10期1033-1042,共10页
Molecular dynamics simulation of uniaxial tension along [001] has been performed to study the influence of various surface defects on the initiation of plastic deformation and fracture of γ-TiAl single crystals.The r... Molecular dynamics simulation of uniaxial tension along [001] has been performed to study the influence of various surface defects on the initiation of plastic deformation and fracture of γ-TiAl single crystals.The results indicate that brittle fracture occurs in perfect bulk; surfaces and edges will be detrimental to the strength of materials and provide dislocation nucleation site. The defects on surfaces and edges cause further weakening with various effects depending on defect type, size, position and orientation,while the edge dimples are the most influential. For γ-TiAl rods with surface dimples, dislocations nucleate from an edge of the rod when dimples are small, dimple dislocation nucleation occurs only when the dimples are larger than a strain rate dependent critical size. The dislocations nucleated upon [001]tension are super dislocations with Burger vectors <011] or 1/2 < 112] containing four 1/6 < 112 > partials. The effects of surface scratches are orientation and shape sensitive. Scratches parallel to the loading direction have little influence, while sharp ones perpendicular to the loading direction may cause crack and thus should be avoided. This simulation also shows that, any type of surface defect would lower strength,and cause crack in some cases. But some may facilitate dislocation nucleation and improve ductility of TiAl if well controlled. 展开更多
关键词 TIAL基合金 分子动力学模拟 表面缺陷 脆性断裂 拉伸变形 缺陷类型 表面划痕 加载方向
Microstructures and Hardness Properties for β-Phase Ti-24Nb-4Zr-7.9Sn Alloy Fabricated by Electron Beam Melting
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作者 J. Hernandez S.J. Li +11 位作者 E. Martinez L.E. Murr X.M. Pan K.N. Amato X.Y. Cheng F. Yang C.A. Terrazas S.M. Gaytan Y.L. Hao R. Yang F. Medina R.B. WickeR 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2013年第11期1011-1017,共7页
Atomized,pre-alloyed Ti—24Nb—4Zr—7.9Sn(wt%) powder was used to fabricate solid,prototype components by electron beam melting(EBM).Vickers microindentation hardness values were observed to average 2 GPa for the prec... Atomized,pre-alloyed Ti—24Nb—4Zr—7.9Sn(wt%) powder was used to fabricate solid,prototype components by electron beam melting(EBM).Vickers microindentation hardness values were observed to average 2 GPa for the precursor powder and 2.5 GPa for the solid,EBM-fabricated products.The powder and solid product microstructures were examined by optical and electron microscopy.X-ray diffraction analyses showed that they had bcc β-phase microstructure.However,it was found by transmission electron microscopy that the EBM-fabricated product had plate morphology with space ~ 100—200 nm.Although the corresponding selected area diffraction patterns can be indexed by β-phase plus α '-martensite with orthorhombic crystal structure,the dark-field analyses failed to observe the a'-martensite.Such phenomenon was also found in deformed gum metals and explained by stress-induced diffusion scattering due to phonon softening. 展开更多
关键词 电子束熔炼 预合金化 硬度值 显微组织 X-射线衍射分析 透射电子显微镜 属性 固体产物
eui胞质雄性不育系的培育及其在杂交水稻育种中的应用 预览
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作者 R.Yang 何平 《国外作物育种》 2002年第2期 13-14,共2页
关键词 eui胞质 雄性不育系 培育 杂交水稻 育种 水稻
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电站凝汽器性能的数值模拟 被引量:11
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作者 杨善让 孙光 《中国电机工程学报》 EI CSCD 北大核心 1990年第0期 92-98,共7页
基于国外应用有限差分计算凝汽器横断面上的二维流动和传热性能的基础上,本文提出了一种考虑冷却水温升所引起的轴向效应的凝汽器性能的数值计算方法。文中作为应用实例给出了国产600MW机组凝汽器的数值模拟结果。本程序可供电站凝汽器... 基于国外应用有限差分计算凝汽器横断面上的二维流动和传热性能的基础上,本文提出了一种考虑冷却水温升所引起的轴向效应的凝汽器性能的数值计算方法。文中作为应用实例给出了国产600MW机组凝汽器的数值模拟结果。本程序可供电站凝汽器优化设计和性能分析时参考。 展开更多
关键词 电站 汽轮机 凝汽器 数值模拟
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Novel transcatheter aortic heart valves exhibiting excellent hemodynamic performance and low-fouling property
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作者 F.Guo K.Jiao +4 位作者 Y.Bai J.Guo Q.Chen R.Yang X.Zhang 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第1期207-215,共9页
Transcatheter aortic heart valves(TAHVs) have been widely used for aortic valve replacements, with less trauma and lower clinical risk compared with traditional surgical heart valve replacements. In the present study,... Transcatheter aortic heart valves(TAHVs) have been widely used for aortic valve replacements, with less trauma and lower clinical risk compared with traditional surgical heart valve replacements. In the present study, composites of poly(ethylene glycol) diacrylate(PEGDA) hydrogels and anisotropic highshrinkage polyethylene terephthalate/polyamide6(PET-PA6) fabric(PEGDA/PET-PA6) were fabricated as artificial heart valve leaflets. Dynamic mechanical analyses(DMA) indicated that PEGDA/PET-PA6 composites possessed anisotropic mechanical properties(i.e., storage moduli ~23.30 ± 1.36 MPa parallel to the aligned fabric fibers and ~9.68 ± 0.90 MPa perpendicular to the aligned fibers at 1 Hz) that were comparable to aortic valve leaflets. The PEGDA/PET-PA6 composites with smooth surfaces were highly hydrophilic(contact angle ~41.6°± 3.8°) and had low-fouling properties without platelet adhesion,suggesting a low risk of thrombogenicity when they interacted with blood. Furthermore, transcatheter aortic heart valves were fabricated using nitinol self-expanding frames and PEGDA/PET-PA6 composites as artificial leaflets, which presented excellent hemodynamic performance with a large orifice area(1.75cm2) and low regurgitation(3.41%), thus meeting the requirements of ISO 5840-3 standard. Therefore,PEGDA/PET-PA6 composites had suitable mechanical properties, good biocompatibility, and low-fouling properties, indicating that they might be used for TAHVs in the future. 展开更多
关键词 TRANSCATHETER AORTIC heart valve Textile fabric Poly(ethylene glycol)diacrylate ANTI-FOULING
超级贝氏体钢的热处理 预览
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作者 H.T. Chang H.W. Yen +3 位作者 W.T. Lin C.Y. Huang J.R. Yang 顾剑锋 《热处理》 CAS 2015年第6期44-50,共7页
研究了分别含有0.0005%(质量分数)和0.0024%(质量分数)硼的两种试验用高硅高碳钢以获得超级贝氏体组织。奥氏体化后,试样分别在3种不同的等温温度(150℃、200℃和300℃)保温不同时间。采用带有显微硬度测定的光学显微镜和透... 研究了分别含有0.0005%(质量分数)和0.0024%(质量分数)硼的两种试验用高硅高碳钢以获得超级贝氏体组织。奥氏体化后,试样分别在3种不同的等温温度(150℃、200℃和300℃)保温不同时间。采用带有显微硬度测定的光学显微镜和透射电镜观察试样的微观组织。结果表明,200℃等温转变10天后,两种钢均获得了高体积分数的含有纳米级贝氏体铁素体亚单元的束状组织,具有高达675HV1的超高显微硬度。添加0.0024%(质量分数)硼能促进200℃等温处理初期的贝氏体相变,但对缩短相变的完成时间没有明显的影响。在150℃和300℃等温不能得到大量的贝氏体组织。 展开更多
关键词 贝氏体 热处理 相变 纳米级组织 TEM
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肺内孤立性球形病灶的X线诊断与影像学研究 预览
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作者 刘冰 荣阳 +4 位作者 胡晓丹 赵明明 李兆丰 夏涛 荣根满 《中国医药指南》 2013年第4期12-13,共2页
目的探讨肺内孤立性球形病灶的X线特点与影像诊断价值。方法对20例周围型肺癌,20例肺结核瘤,20例肺炎性假瘤的X线特征进行比较,其中38例经手术证实,22例经CT及临床治疗观察证实。结果初片误诊28例,将肺癌误诊为炎性假瘤8例、结核瘤4例;... 目的探讨肺内孤立性球形病灶的X线特点与影像诊断价值。方法对20例周围型肺癌,20例肺结核瘤,20例肺炎性假瘤的X线特征进行比较,其中38例经手术证实,22例经CT及临床治疗观察证实。结果初片误诊28例,将肺癌误诊为炎性假瘤8例、结核瘤4例;结核瘤误诊为肺癌4例;炎性假瘤误诊为肺癌4例、结核瘤8例,误诊率达46.67%。结论对三种肺内孤立性球形病灶的X线作出诊断必须做到:阅片认真、考虑周全,并必须结合临床表现进行综合分析。 展开更多
关键词 肺内 孤立性球形病灶 X线诊断 影像分析
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Superplasticity of Ti2448 Alloy with Nanostructured Grains 被引量:1
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作者 M.J. Xiao Y.X. Tian +3 位作者 G. W. Mao S.J. Li Y.L. Hao R. Yang 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2011年第12期 1099-1104,共6页
Ti-24Nb-4Zr-8Sn, abbreviated as Ti2448 from its chemical composition in weight percent, is a multifunctional β type titanium alloy with body centered cubic (bcc) crystal structure, and its highly localized plastic de... Ti-24Nb-4Zr-8Sn, abbreviated as Ti2448 from its chemical composition in weight percent, is a multifunctional β type titanium alloy with body centered cubic (bcc) crystal structure, and its highly localized plastic deformation behavior contributes significantly to grain refinement during conventional cold processing. In the paper, the nanostructured (NS) alloy with grain size less than 50 nm produced by cold rolling has been used to investigate its superplastic deformation behavior by uniaxial tensile tests at initial strain rates of 1.5×10-2, 1.5×10-3 and 1.6×10-4 s-1 and temperatures of 600, 650 and 700℃. The results show that, in comparison with the coarse-grained alloy with size of 50 μm, the NS alloy has better superplasticity with elongation up to ~275% and ultimate strength of 50–100 MPa. Strain rate sensitivity (m) of the NS alloy is 0.21, 0.30 and 0.29 for 600, 650 and 700℃, respectively. These results demonstrate that grain refinement is a valid way to enhance the superplasticity of Ti2448 alloy. 展开更多
TRANSFORMATION BEHAVIOR OF Ti50-x/2Ni50-x/2Cux ALLOYS 预览
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作者 J. Wang W. Jin M.Z. Cao R. Yang 《金属学报:英文版》 SCIE EI CAS CSCD 2006年第6期 391-396,共6页
Phase transformation behavior of Ti50-x/2Ni50-x/2Cux (x=2, 5, 15) alloys was investigated using differential scanning calorimetry (DSC). The results show that Ti50-x/2Ni50-x/2Cux alloys undergo a two-stage martensitic... Phase transformation behavior of Ti50-x/2Ni50-x/2Cux (x=2, 5, 15) alloys was investigated using differential scanning calorimetry (DSC). The results show that Ti50-x/2Ni50-x/2Cux alloys undergo a two-stage martensitic transformation on cooling and transform reversely in one stage on heating when treated at 823K for 5 hours. Heat treatment has no effect on the transformation behavior of Ti49Ni49Cu2 alloy but does influence that of Ti47.5Ni47.5Cu5 alloy and Ti42.5Ni42.5Cu15 alloy. Effect of heat treatment is related with precipitation of CuNiTi phase. The maximum recoverable elongation of Ti49Ni49Cu2 wire is about 6%. 展开更多
关键词 microstructure TRANSFORMATION SHAPE MEMORY TI-NI-CU
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Comparing two arsenic trioxide administration methods in APL therapy 被引量:5
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作者 周晋 孟然 杨宝峰 《中华医学杂志:英文版》 SCIE CAS CSCD 2004年第9期 1411-1413,共3页
Arsenic trioxide (As2O3) was approved for the treatment of acute promyelocytic leukemia (APL) and was under investigation for other malignancies. However, some side effects occurred during APL treatment with routine A... Arsenic trioxide (As2O3) was approved for the treatment of acute promyelocytic leukemia (APL) and was under investigation for other malignancies. However, some side effects occurred during APL treatment with routine As2O3 infusion. We tried a ' continuously slow As2O3 intravenous infusion ' method and assessed its effectiveness and security in APL treatment. 展开更多
关键词 三氧化砷 给药方法 APL 治疗方法 AS2O3 急性 髓细胞
MARTENSITE AND REVERSE TRANSFORMATION IN PRESTRAINED TiNi SHAPE MEMORY ALLOY THIN FILM 预览
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作者 X.P.Liu M.Z.Cao R.Yang 《金属学报:英文版》 SCIE EI CAS CSCD 2003年第3期 221-225,共5页
The effect of pre-strain on phase transformation of TiNi shape memory alloy film was studied by differential scanning calorimeter measurement (DSC). Compared with un deformed TiNi film, the reverse transformation of p... The effect of pre-strain on phase transformation of TiNi shape memory alloy film was studied by differential scanning calorimeter measurement (DSC). Compared with un deformed TiNi film, the reverse transformation of pre-strained specimens was elevated to a higher temperature on the first heating, but martensite and reverse transforma tion on subsequent thermal cycles occurred at a lower temperature. The evolution of transformation behavior in pre-strained TiNi film was related to the change of elastic strain energy, irreversible energy and internal stress field. 展开更多
关键词 形状记忆合金 薄膜 TINI合金 马氏体相变 预应变
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巡游铁磁体SrRuO3磁性的Preisach描述 预览
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作者 侯登录 姜恩永 +3 位作者 R.M.Roshko 杨连祥 唐贵德 聂向富 《材料研究学报》 EI CAS CSCD 北大核心 2002年第6期 575-579,共5页
测量了巡游铁磁体SrRuO3的零场冷却(ZFC)和加场冷却(FC)的磁化强度随温度的变化关系,以及不同温度下的磁滞回线.考虑了热涨落和自由能壁垒随温度的变化,改进了Preisach模型并对测量数据进行了拟合.数值模拟再现了测量结果的变化规律,包... 测量了巡游铁磁体SrRuO3的零场冷却(ZFC)和加场冷却(FC)的磁化强度随温度的变化关系,以及不同温度下的磁滞回线.考虑了热涨落和自由能壁垒随温度的变化,改进了Preisach模型并对测量数据进行了拟合.数值模拟再现了测量结果的变化规律,包括在不同温度下的磁滞回线和在不同外磁场下的ZFC和FC磁化强度曲线等.对拟合出的巴克豪森跳跃谱进行了讨论. 展开更多
关键词 巡游铁磁体 SRRUO3 磁性 PREISACH模型 铁磁性材料 不可逆过程 磁滞回线 磁化强度
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应用神经网络和多元回归技术预测森林产量 预览 被引量:24
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作者 浦瑞良 Yang,R 《应用生态学报》 CAS CSCD 1999年第2期 129-134,共6页
应用传统统计技术常会因样本小和测量数据不符某各分布而受到限制。本文评价一种前馈型神经钢络算法以预测落叶阔叶林产量。另外,还介绍一种由定性变为定量的数据变换方法,以及相对小的样本建立多元回归预测模型。数据变换方法有助于... 应用传统统计技术常会因样本小和测量数据不符某各分布而受到限制。本文评价一种前馈型神经钢络算法以预测落叶阔叶林产量。另外,还介绍一种由定性变为定量的数据变换方法,以及相对小的样本建立多元回归预测模型。数据变换方法有助于改善多元回归模型的预测效果。研究结果表明神经网络技术能够产生最好的预测效果。 展开更多
关键词 神经网络 多元回归 森林产量 预测 数据变换
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STUDY ON DISLOCATION STRUCTURES IN WELDED METALS UNDER FATIGUE LOAD 预览
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作者 Yang, H.R. 《金属学报:英文版》 SCIE EI CAS CSCD 1999年第4期340-344,共5页
关键词 FATIGUE load weled BUTT jiont TEM observe DISLOCATION arrangement crackinitiation
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THE DETERMINATION OF THE RESIDUAL STRESS DURING THE FATIGUE CRACK EXTENDSION 预览
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《金属学报:英文版》 SCIE EI CAS CSCD 1999年第4期725-727,共3页
关键词 CRACK EXTENSION WELD RESIDUALSTRESS
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