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Mg-3Sm-0.5Zn-0.4Zr合金的高温蠕变机制和组织演变

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中国科学：技术科学 2024年第6期54卷 1079-1090页

作者：夏利红郑江王渠东重庆工商大学智能装备绿色设计与制造重庆市重点实验室重庆400067 重庆大学国家镁合金材料工程技术研究中心重庆400044 上海交通大学轻合金精密成型国家工程研究中心上海200240

提升镁合金的高温抗蠕变性能是其能够在汽车动力系统得到广泛应用的关键.对耐热镁合金蠕变变形机制和组织演变缺乏系统研究,是限制其发展的重要因素.本文以低稀土镁合金(Mg-3Sm-0.5Zn-0.4Zr合金)为研究对象,将蠕变应力指数计算、滑移迹... 详细信息

提升镁合金的高温抗蠕变性能是其能够在汽车动力系统得到广泛应用的关键.对耐热镁合金蠕变变形机制和组织演变缺乏系统研究,是限制其发展的重要因素.本文以低稀土镁合金(Mg-3Sm-0.5Zn-0.4Zr合金)为研究对象,将蠕变应力指数计算、滑移迹线和析出相观察相结合,系统分析了重力铸造和高压铸造Mg-3Sm-0.5Zn-0.4Zr合金在200℃~250℃/60~100 MPa条件下的变形模式和组织演变.主要结果为:重力铸造和高压铸造Mg-3Sm-0.5Zn-0.4Zr合金在200℃/60 MPa条件下稳态蠕变速率分别为1.4×10^(-9)s^(-1)和1.1×10^(-9)s^(-1),表明其具有优异的抗蠕变性能.200°C~250℃/60 MPa条件下,高压铸造合金具有比重力铸造合金更低的稳态蠕变速率.在200℃60~100 MPa条件下,两种合金的主要变形机制均为基面滑移.在225℃条件下,当σ≤80 MPa,基面滑移仍然是两种合金的主要变形模式;当σ>80 MPa,两种合金的变形模式为基面滑移、非基面滑移和孪生.在250℃/60~70 MPa条件下,基面滑移和非基面滑移是两种合金的主要变形模式.此外,重力铸造和高压铸造合金在蠕变过程中均会发生动态析出,形成大量与基面垂直的析出相.与重力铸造合金相比,高压铸造合金具有更多细小的析出相,可有效阻碍位错滑移,这是其具有优异抗蠕变性能的重要因素.

关键词：镁合金高压铸造蠕变模式组织演变动态析出

IN SITU　GRADIENT　DOUBLE-LAYER　COMPOSITES　OF　Al-Fe　ALLOY　BY　CENTRIFUGAL　CASTING

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中国有色金属学会会刊：英文版 1997年第1期7卷 126-131页

作者： wang, qudong Dalian Univ of technology Dalian China

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ＩＮＳＩＴＵＧＲＡＤＩＥＮＴＤＯＵＢＬＥＬＡＹＥＲＣＯＭＰＯＳＩＴＥＳＯＦＡｌＦｅＡＬＬＯＹＢＹＣＥＮＴＲＩＦＵＧＡＬＣＡＳＴＩＮＧ①ＷａｎｇＱｕｄｏｎｇ，ＪｉｎＪｕｎｚｅＲｅｓｅａｒｃｈＣｅｎｔｅｒｏｆＦｏｕｎｄｒｙＥｎｇｉｎｅｒｉｎｇ，Ｄａｌ...

关键词： in situ composites gradient composites double layer composites Al Fe alloy centrifugal casting

Microstructure and Mechanical Properties of Overcast 6101–6101 Wrought Al Alloy Joint by Squeeze Casting

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Journal of Materials Science & Technology 2016年第4期32卷 298-304页

作者： Teng Liu qudong wang YudongSui Qigui wang National Engineering Research Center of Light Alloys Net Forming and State Key Laboratory of Metal Matrix Composite Shanghai Jiao Tong University200030ShanghaiChina General Motors Global Powertrain Engineering 823 Joslyn AvenuePontiacMI 48340-2920USA

The wrought Al alloy-wrought Al alloy overcast joint was fabricated by casting liquid 6101 Al alloy onto 6101 Al extrusion bars and solidifying under applied pressure. The joint interfacial microstructure was investigated; the effect of applied pressure on the microstructure and mechanical properties was evalu- ated. The mechanism of joint formation and mechanical behaviors of both squeeze cast 6101 and 6101- 6101 overcastjoint material were analyzed. The results show that with the application of pressure during solidification process, wrought Al alloy 6101 could be cast directly into shape successfully. Excellent met- allurgical bonding was then formed in the overcast joint by electro-plating 6101 solid insert with a layer of zinc coating, and a transition zone formed in the joint region. During the tensile test, the fracture occurs in the 6101 solid insert part with the ultimate tensile strength （UTS） of 200 MPa, indicating that the strength of the overcast joint is higher than 200 MPa, and the tensile strength of overcast joint material is inde- pendent on the magnitude of applied pressure. For Al-Al overcast joint material, if a clean and high strength joint is formed, the UTS and yield strength （YS） are determined by the material with the lower value, while for EL, the value is determined by the length proportion and the stress-strain behavior of both components.

关键词： Aluminum alloyOvercastingSqueeze castingInterfaceMicrostructureMechanical properties

Effective inhibition of anomalous grain coarsening in cast AZ91 alloys during fast cooling via nanoparticle addition

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Journal of Magnesium and Alloys 2023年第12期11卷 4575-4588页

作者： Haonan Li Kui wang Gaopeng Xu Haiyan Jiang qudong wang Yingxin wang National Engineering Research Center of Light Alloy Net FormingShanghai Jiao Tong University200240ShanghaiP.R.China State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University200240ShanghaiP.R.China

In this work, the effects of Ti CN and γ-Al_(2)O_(3) nanoparticle(NP) addition on the microstructural evolution of cast AZ91 alloys at the cooling rate ranging from 15 to 120 K/s have been systematically investigated. Experimental results reveal that grain coarsening occurs in cast AZ91 alloys when the cooling rate exceeds 90 K/s, while it can be effectively inhibited upon addition of NPs. The marked inhibition effect may originate from the formation of Ti CN or γ-Al_(2)O_(3) NP-induced undercooling zone ahead of solid/liquid(S/L) front of α-Mg, which not only can restrict grain growth effectively, but also can reactivate the native nucleants that are inactive in AZ91 melts to participate in nucleation events. And if possessing high nucleation potency, NPs can also promote further nucleation events and lead to significant grain refinement. An analytical model has been established to quantitatively account for the restriction effect of NPs on grain growth. The present work may shed a new light on the grain coarsening of cast alloys during fast cooling and provide an effective approach to circumvent it.

关键词： Grain coarsening Nanoparticles Undercooling zone Fast cooling

Enhanced Strength and Ductility Due to Microstructure Refinement and Texture Weakening of the GW102K Alloy by Cyclic Extrusion Compression

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Journal of Materials Science & Technology 2016年第8期32卷 783-789页

作者： Jinbao Lin Xinyi wang Weijie Ren Xuexia Yang qudong wang School of Applied Science Taiyuan University of Science and Technology National Engineering Research Center for Light Alloy Net Forming Shanghai Jiao Tong University

The cyclic extrusion compression （CEC） was applied to severely deform the as-extruded GW102K （Mg- 10.0Gd-2.0Y-0.5Zr, wt%） alloy at 350, 400, and 450 ℃, respectively. The microstructure, texture, and grain boundary character distribution of the CECed alloy were investigated in the present work. The mechan- ical properties were measured by uniaxial tension at room temperature. The crack initiation on the longitudinal section near the tensile fracture-surface was investigated by high-resolution scanning elec- tron microscopy （SEM）. The result shows that the microstructure was dramatically refined by dynamic recrystallization （DRX）. The initial fiber texture was disintegrated and obviously weakened. The 8-passes/ 350 ℃ CECed alloy exhibited yield strength of 318 MPa with an elongation-to-fracture of 16.8%, increased by 41.3% and 162.5%, respectively. Moreover, the elongation-to-fracture of the 8-passes/450 ℃ CECed alloy significantly increased more than 3 times than that of the received alloy. The cracks were mainly initi- ated at twin boundaries and second phase/matrix interfaces during tensile deformation. The microstructure refinement was considered to result in the dramatically enhanced of the strength and ductility. In ad- dition, the texture randomization during CEC is beneficial for enhancing ductility. The standard positive Hall-Petch relationships have been obtained for the CECed GW102K alloy.

关键词： Cyclic extrusion compression (CEC) Mechanical properties Magnesium alloy Electron hackscatter diffraction (EBSD) Texture

Damping performance of SiC nanoparticles reinforced magnesium matrix composites processed by cyclic extrusion and compression

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Journal of Magnesium and Alloys 2023年第5期11卷 1608-1617页

作者： Mahmoud Ebrahimi Li Zhang qudong wang Hao Zhou Wenzhen Li National Engineering Research Center of Light Alloy Net Forming and Key State Laboratory of Metal Matrix Composites School of Material Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240PR China School of Mechanical Engineering North University of ChinaTaiyuan 030051PR China Nano and Heterogeneous Materials Center School of Materials Science and EngineeringNanjing University of Science and TechnologyNanjing 210094PR China School of Materials Science and Engineering Tsinghua UniversityBeijing 10084PR China

This work dealt with the damping performance and its underlying mechanism in SiC nanoparticles reinforced AZ91D composite(SiC_(np)/AZ91D)processed by cyclic extrusion and compression(CEC).It was found that the CEC process significantly affects the damping performance of the composite due to alterations in the density of dislocations and grain boundaries in the matrix *** there would be dynamic precipitation of the Mg17Al12 phase during processing which increases the phase interface and limits the mobility of dislocations and grain *** results also showed that the damping capacity of 1%SiC_(np)/AZ91D composite continuously decreases with adding CEC pass number and it consistently increases with rising the applied *** the first derivative of the tanδ-T curve,the dominant damping mechanism based on test temperature can be divided into three *** three regions are as follows(i)dislocation vibration of the weak pinning points(≤T_(cr)),(ii)dislocation vibration of the strong pinning points(T_(cr)∼T_(V)),and(iii)grain boundary/interface sliding(≥T_(V))

关键词： Metal matrix composite SiC nanoparticles Severe plastic deformation Temperature-dependent damping curves Damping mechanism

Effects of aging on the microstructures and mechanical properties of extruded AM50+xCa magnesium alloys

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Rare Metals 2006年第4期25卷 377-381页

作者： wang qudong PENG Jianguo Suéry Michel Jean-Jacques Blandin National Engineering Research Centre of Light Alloys Net Forming School of Materials Science and Engineering Shanghai Jiaotong UniversityShanghai 200030 China Institute National Polytechnique de Grenoble （INPG） Génie Physique et Mécanique des Matériaux （GPM2） UMR CNRS 5010 ENSPG BP46 38402 Saint-Martin d＇Héres Cedex France

The effects of aging treatment on the microstructures and mechanical properties of extruded AM50 ＋ xCa alloys （x=0, 1, 2 wt.%） were studied. The results indicated the secondary phase Mgl7Al12 precipitated from the saturated α-Mg solid solution while Al2Ca changed slightly when the aging time was increased. The hardness of extruded AM50 ＋ xCa al- loys increased initially to its peak, and then dropped to reach its original hardness with the increase in aging time. With the increase in aging temperature, the hardness of the AM50 ＋ 2Ca ahoy decreased, whereas the hardness of AM50 and AM50 ＋ 1Ca alloys decreased in the initial stages of aging treatment and increased in the later stages of aging treatment. The tensile strengths of AM50 and AM50 ＋ 1Ca alloys increased after aging treatment for the precipitation of Mg17Al12 phase, which increases the resistance against dislocation movement at the grain boundary; with increase in aging temperature, their tensile strengths increased. For AM50 ＋ 2Ca alloy, the tensile strength declined after aging at 150℃ and 175℃, while it increased slightly at 200℃. The ductility of AM50 ＋ xCa alloys （x = 0, 1, 2 wt.%） declined after aging treatment.

关键词： AM50 + xCa alloys aging extrusion mechanical properties

Tensile and Isothermal Fatigue Behaviors of Mg-12Gd-3Y-0.5Zr Alloy at High Temperature

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Journal of Materials Science & Technology 2009年第6期25卷 731-737页

作者： Xiaoming Yang Huajie Yang Fan Yang Shuming Yin Wei wang Shouxin Li qudong wang Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China National Engineering Research Center of Light Alloys Net Forming Shanghai Jiao Tong University Shanghai 200020 China

Tensile and isothermal fatigue tests were carried out on an as-rolled Mg-12Gd-3Y-0.5Zr alloy and its heat-treated counterpart at different temperatures. The experimental results show that the ultimate tensile strengths of two alloys decrease very slowly with increasing temperature up to 200℃. The ultimate tensile strength of heat-treated Mg-12Gd-3Y-0.5Zr is slight lower than that of as-rolled counterpart; however, the fatigue strength of heat-treated alloy is higher. The mechanism of fatigue failure was investigated by scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. It shows that cyclic slip combined with environmental effect may be the main crack initiation mechanism.

关键词： Mg-12Gd-3Y-0.5Zr Isothermal fatigue Fatigue strength Tensile strength

Effects of Gd Addition on the Microstructure and Tensile Properties of Mg–4Al–5RE Alloy Produced by Three Different Casting Methods

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Acta Metallurgica Sinica(English Letters) 2021年第10期34卷 1361-1374页

作者： Jie Wei qudong wang Li Zhang Mahmoud Ebrahimi Haiyan Jiang Wenjiang Ding National Engineering Research Center of Light Alloy Net Forming and Key State Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China

This work deals with the effect of 0.67 wt%Gd addition on the microstructure and tensile properties of Mg–4 Al–5 RE(where RE represents La–Ce mischmetal)alloy produced by sand casting(SC),permanent mold casting(PMC),and high-pressure die casting(HPDC).The results show that Gd addition could refine the grains,but its efficiency decreases by increasing the cooling rate due to the shifting from SC to PMC and finally to the HPDC ***,the acicular Al11 RE3 phase is modified into the short-rod or granular-like shape under the three casting *** refined and modified microstructures are due to the Al2(Gd,RE)phases,which act as the nucleation sites in both theα-Mg matrix and Al11 RE3 ***,the weakening grain refinement effect in the increased cooling rates can be attributed to the narrow constitutional undercooling *** Gd addition,the 0.2%proof strength of the SC and PMC alloys increases by about 16.9%and 12.7%,respectively,while in the HPDC alloy,it decreases by about 5.9%.The main factor in the strength increment of the SC and PMC alloys is the grain boundary strengthening due to grain refinement which is proved by modeling the related mechanisms,whereas weak secondary phases and grain boundary strengthening mechanisms in the HPDC alloy lead to strength *** Gd addition,the elongation to failure of the SC,PMC,and HPDC alloys is significantly enhanced by about 34.8%,20.2%,and 12.3%,respectively,due to the crack resistance nature of the modified short-rod/granular Al11(RE,Gd)3 phase compared to the acicular one.

关键词： Magnesium alloy Gadolinium Grain refinement Strengthening mechanism