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1Research advances in magnesium and magnesium alloys worldwide in 2020显示文摘Research on magnesium alloys continues to attract great attention,with more than 3000 papers on magnesium and magnesium alloys published and indexed in SCI in 2020 alone.The results of bibliometric analyses show that microstructure control and mechanical properties of Mg alloys are continuously the main research focus,and the corrosion and protection of Mg alloys are still widely concerned.The emerging research hot spots are mainly on functional magnesium materials,such as Mg ion batteries,hydrogen storage Mg materials,and bio-magnesium alloys.Great contributions to the research and development of magnesium alloys in 2020 have been made by Chongqing University,Chinese Academy of Sciences,Central South University,Shanghai Jiaotong University,Northeastern University,Helmholtz Zentrum Geesthacht,etc.The directions for future research are suggested,including:1)the synergistic control of microstructures to achieve high-performance magnesium alloys with concurrent high strength and superior plasticity along with high corrosion resistance and low cost;2)further development of functional magnesium materials such as Mg batteries,hydrogen storage Mg materials,structural-functional materials and bio-magnesium materials;3)studies on the effective corrosion protection and control of degradation rate of magnesium alloys;4)further improvement of advanced processing technology on Mg alloys.Yan Yang Xiaoming Xiong Jing Chen Xiaodong Peng Daolun Chen Fusheng Pan 2021Journal of Magnesium and Alloys2021,9,3:52
2Effect of rare earth elements and their oxides on tribo-mechanical performance of laser claddings:A review显示文摘Laser cladding is a promising photon-based surface engineering technique broadly utilized for fabricating harder and wear resistant composite coatings. In spite of excellent properties, the practical applications of laser claddings are relatively restricted when compared with well-established coating techniques because of their inherent defects identified as cracks, pores and inclusions. Substantial evidence suggests that the incorporation of an appropriate amount of rare earth in laser claddings can remarkably prevent these defects. Additionally, the presence of rare earth in laser claddings can notably enhance tribo-mechanical properties such as surface hardness, modulus of elasticity, fracture toughness, friction coefficient and wear rate. In this literature review, the effect of rare earth in reducing dilution and cracks susceptibility of laser claddings in addition to microstructural refinement attained was examined. Mechanical and tribological properties of these claddings along with their underlying mechanism were discussed in detail. Finally, this article summarizes current applications of laser claddings based on rare earth and was concluded with future research directions.M.M.Quazi M.A.Fazal A.S.M.A.Haseeb Farazila Yusof H.H.Masjuki A.Arslan 2016Journal of Rare Earths2016,34,6:48
3Progress in additive manufacturing on new materials: A review显示文摘Recent efforts and advances in additive manufacturing(AM) on different types of new materials are presented and reviewed. Special attention is paid to the material design of cladding layers, the choice of feedstock materials, the metallurgical behavior and synthesis principle during the AM process, and the resulted microstructures and properties, as well as the relationship between these factors. Thereafter,the trend of development in the future is forecasted, including: Effects of the particles size and size distribution of powders; Approaches for producing fine microstructures; Opportunities for creating new materials by AM; Wide applications in reconditioning of damaged components; Challenges for deep understanding and applications of the AMed new materials. The idea of 'Develop Materials' or 'Create Materials' by AM is highlighted, but a series of scientific, technological and engineering problems remain to be solved in future.Neng Li Shuai Huang Guodong Zhang Renyao Qin Wei Liu Huaping Xiong Gongqi Shi Jon Blackburn 2019Journal of Materials Science & Technology2019,35,2:47
4固溶温度对激光立体成形GH4169高温合金组织和性能的影响(英文)显示文摘研究激光立体成形GH4169高温合金固溶处理后的组织,分析了固溶过程中合金元素的均匀化,并对材料显微硬度的变化做了讨论。结果表明,随固溶温度的升高,材料的晶界越来越清晰,经1000-1170°C固溶处理1h后材料发生再结晶,当固溶处理温度高于1100°C,有大量孪晶出现,晶粒相比沉积态显著细化,晶粒尺寸约200μm。合金元素的均匀化在1100°C保温1h后基本完成。显微硬度测试结果显示,材料的显微硬度值随固溶温度的升高而降低,在固溶温度低于1100°C时减小趋势较快,高于1100°C时减小趋势减缓。显微硬度的变化与材料中γ′和γ'相及δ相的形态和数量有关。1100°C是激光立体成形GH4169合金比较合适的固溶处理温度下限。刘奋成 林鑫 赵卫卫 赵晓明 陈静 黄卫东 2010稀有金属材料与工程2010,39,9:29
5Microstructure and mechanical properties of NZ30K alloy by semi-continuous direct chill and sand mould casting processes显示文摘The Mg-3.0Nd-0.2Zn-0.4Zr (NZ30K) alloys were prepared by direct-chill casting (DCC) and sand mould casting (SMC) processes,respectively and their microstructures and mechanical properties were investigated.The results indicate that casting method plays a remarkable influence on the microstructure and mechanical properties of as-cast NZ30K alloy.The grain size increases from 35-40μm in the billets made by the DCC to about 100-120μm in the billets by the SMC.The aggregation of Mg12Nd usually found at the triple joints of grain boundaries in the billets prepared by SMC while is not observable from the billets by DCC.The tensile strengths and elongations of the billets are 195.2 MPa and 15.5% by DCC,and 162.5 MPa and 3.2% by SMC,respectively.The tensile strength of the alloy by DCC is remarkably enhanced by T6 heat treatment,which reached 308.5 MPa.Fracture surfaces of NZ30K alloy have been characterized as intergranular fracture by SMC and quasi-cleavage fracture by DCC,respectively.Zheng Xingwei Dong Jie Liu Wencai Ding Wenjiang 2011China Foundry2011,8,1:25
6Diffusion kurtosis imaging of microstructural changes in brain tissue affected by acute ischemic stroke in different locations显示文摘The location of an acute ischemic stroke is associated with its prognosis. The widely used Gaussian model-based parameter, apparent diffusion coefficient(ADC), cannot reveal microstructural changes in different locations or the degree of infarction. This prospective observational study was reviewed and approved by the Institutional Review Board of Xiamen Second Hospital, China(approval No. 2014002).Diffusion kurtosis imaging(DKI) was used to detect 199 lesions in 156 patients with acute ischemic stroke(61 males and 95 females), mean age 63.15 ± 12.34 years. A total of 199 lesions were located in the periventricular white matter(n = 52), corpus callosum(n = 14), cerebellum(n = 29), basal ganglia and thalamus(n = 21), brainstem(n = 21) and gray-white matter junctions(n = 62). Percentage changes of apparent diffusion coefficient(ΔADC) and DKI-derived indices(fractional anisotropy [ΔFA], mean diffusivity [ΔMD], axial diffusivity [ΔD_a], radial diffusivity ΔDr, mean kurtosis [ΔMK], axial kurtosis [ΔK_a], and radial kurtosis [ΔK_r]) of each lesion were computed relative to the normal contralateral region. The results showed that(1) there was no significant difference in ΔADC, ΔMD, ΔD_a or ΔD_r among almost all locations.(2) There was significant difference in ΔMK among almost all locations(except basal ganglia and thalamus vs. brain stem; basal ganglia and thalamus vs. gray-white matter junctions; and brainstem vs. gray-white matter junctions.(3) The degree of change in diffusional kurtosis in descending order was as follows: corpus callosum > periventricular white matter > brainstem > gray-white matter junctions > basal ganglia and thalamus > cerebellum. In conclusion, DKI could reveal the differences in microstructure changes among various locations affected by acute ischemic stroke, and performed better than diffusivity among all groups.Liu-Hong Zhu Zhong-Ping Zhang Fu-Nan Wang Qi-Hua Cheng Gang Guo 2019Neural Regeneration Research2019,14,2:26
7Mechanical properties and corrosion behavior of selective laser melted 316L stainless steel after different heat treatment processes显示文摘Irregular grains, high interfacial stresses and anisotropic properties widely exist in 3D-printed metallic materials, and this paper investigated the effects of heat treatment on the microstructural, mechanical and corrosion properties of 316 L stainless steel fabricated by selective laser melting. Sub-grains and low-angle boundaries exist in the as-received selective laser melted(SLMed) 316 L stainless steel. After heat treatment at 1050℃, the sub-grains and low-angle boundaries changed slightly, and the stress state and strength decreased to some extent due to the decrease of dislocation density. After heat treatment at 1200℃, the grains became uniform, and the dislocation cells vanished, which led to a sharp decline in the hardness and strength. However, the ductility was improved after recrystallization heat treatment.The passive film thickness and corrosion potential of the SLMed 316 L stainless steel decreased after heat treatment, and the pitting potential also decreased due to the accelerated transition from metastable to steady-state pitting;this accelerated transition was caused by the presence of weak passive films at the enlarged pores after heat treatment, especially for an adequate solid solution treatment.Decheng Kong Chaofang Dong Xiaoqing Ni Liang Zhang Jizheng Yao Cheng Man Xuequn Cheng Kui Xiao Xiaogang Li 2019Journal of Materials Science & Technology2019,35,7:23
8Enhanced strength and ductility of Mg-Gd-Y-Zr alloys by secondary extrusion显示文摘The Mg-12Gd-3Y-0.6Zr(GW123,wt.%)alloy was prepared by cast,and thermo-mechanically treated by single and secondary hot extrusion techniques.The microstructure,texture and mechanical properties of the extruded alloy were investigated.The results show that in different treated conditions the microstructure is mainly composed ofα-Mg solid solution and second phases of Mg_(3)Y_(3)Gd_(2) and Mg_(5)(GdY)precipitates.The best mechanical properties are achieved in the secondary extruded alloy after ageing,with the ultimate tensile strength(UTS),tensile yield strength(TYS)and elongation(ɛ)being 446 MPa,350 MPa and 10.2%at room temperature.A weak texture aligned with〈101¯0〉||ED(extrusion direction)component and spread from〈101¯0〉to〈112¯0〉poles was obtained in secondary extrusion,which is caused by the occurrence of dynamic recrystallization(DRX)in shear bands for texture randomization.The fracture modes in extruded GW123 alloy are mixed pattern of transgranular and intergranular fracture,as well as cleavage fracture.The strengthening mechanisms were quantitatively analysed from the different aspects using the measured microstructural parameters.The grain boundaries and solid solution strengthening were the main contributors to the high tensile strength of the GW123 alloy.X.Li W.Qi K.Zheng N.Zhou 2013Journal of Magnesium and Alloys2013,1,1:21
9Changes in distribution and microstructure of bauxite residue aggregates following amendments addition显示文摘Bauxite residue is a highly alkaline byproduct which is routinely discarded at residue disposal areas. Improving soil formation process to revegetate the special degraded lands is a promising strategy for sustainable management of the refining industry. A laboratory incubation experiment was used to evaluate the effects of gypsum and vermicompost on stable aggregate formation of bauxite residue. Aggregate size distribution was quantified by fractal theory, whilst residue microstructure was determined by scanning electron microscopy and synchrotron-based X-ray micro-computed tomography. Amendments addition increased the content of macro-aggregates(> 250 μm) and enhanced aggregate stability of bauxite residue. Following gypsum and vermicompost addition, fractal dimension decreased from 2.84 to 2.77, which indicated a more homogeneous distribution of aggregate particles. Images from scanning electron microscopy and three-dimensional microstructure demonstrated that amendments stimulate the formation of improved structure in residue aggregates. Pore parameters including porosity, pore throat surface area, path length, and path tortuosity increased under amendment additions. Changes in aggregate size distribution and microstructure of bauxite residue indicated that additions of gypsum and vermicompost were beneficial to physical condition of bauxite residue which may enhance the ease of vegetation.Shengguo Xue Yuzhen Ye Feng Zhu Qiongli Wang Jun Jiang William Hartley 2019Journal of Environmental Sciences2019,31,4:21
10The precipitation strengthening behavior of Cu-rich phase in Nb contained advanced Fe-Cr-Ni type austenitic heat resistant steel for USC power plant applicationCheng-yu Chi a, Hong-yao Yu b, Jian-xin Dong b, Wen-qing Liu c, Shi-chang Cheng d, Zheng-dong Liu d, Xi-shan Xie b a School of Metallurgical and Ecological Engineering, University of Science & Technology Beijing, Beijing 100083, China b School of Materials Science and Engineering, University of Science & Technology Beijing, Beijing 100083, China c Instrumental Analysis & Research Center, Shanghai University, Shanghai 200444, China d Central Iron and Steel Research Institute, Beijing 100081, China 2012Progress in Natural Science:Materials International2012,22,3:20
11Effect of wheat bran insoluble dietary fiber with different particle size on the texture properties, protein secondary structure, and microstructure of noodles显示文摘This study was conducted to explore how the insoluble dietary fiber(IDF)of wheat bran with different particle size affects the texture properties,water distribution,protein secondary structure and microstructure of noodles.The results suggested that IDF addition increased the cooking loss and decreased the sensory evaluation because of the damage on dough structure,while as the IDF particle size decreased,the sensory score increased from 78.8 to 82.3 and cooking loss decreased from 8.65%to 7.65%,which could be attributed to that small particle-sized IDF limited the damage on protein network structure,decreased the T22 and t-structure,and increased the β1-structure.Moreover,IDF particle size had a significant correlation with protein secondary structures,texture properties and evaluation score of noodles.In conclusion,adding appropriate particle sizewould be an effectiveway of enhancing the nutritional and textural properties of noodles.Jian Zhang Mengqin Li Chaoran Li Yanqi Liu 2019Grain & Oil Science and Technology2019,2,4:20
12Effect of Y and Gd content on the microstructure and mechanical properties of Mg-Y-RE alloys显示文摘In the application of WE43,it is found that Y_(2)O_(3)inclusion formed in the process of casting seriously reduced the mechanical properties of the products.The reduction of the mechanical properties is even more distinct when it comes to the application in the thin walled complex-precision castings.In order to decrease the Y_(2)O_(3)inclusions,Gd element was used to replace part of the Y element in Mg-Y-RE series alloys.The effect of Y content(Mg-x Y-1Gd-2Nd-0.5Zn-0.5Zr)and Y/Gd ratio(Mg-x Y-(5-x)Gd-2Nd-0.5Zn-0.5Zr)on the microstructure and mechanical properties of Mg-Y-RE alloys were investigated in this paper.With decreasing Y content,the grain size of the alloys increased,both ultimate tensile strength(UTS)and yield strength(YS)of alloys decreased monotonically.Replacing part of Y content with Gd and keeping the total rare earth content unchanged,the low Y content Mg-2Y-3Gd-2Nd-0.5Zn-0.5Zr alloy showed the same mechanical properties as the high Y content Mg-4Y-1Gd-2Nd-0.5Zn-0.5Zr alloy at both room and elevated temperatures.After solution treatment at 525°C for 8 h and aging treatment at 225°C for 10 h,the UTS,YS and elongation(ε)of Mg-2Y-3Gd-2Nd-0.5Zn-0.5Zr alloy reached 281.7 MPa,198 MPa and 11.1%at room temperature,and 216.7 MPa,171.6 MPa and 16.1%at 250°C.The new low Y content Mg-2Y-2Nd-3Gd-0.5Zn-0.5Zr alloy is expected to replace the high Y content WE43 alloys,which can be used in the complex thin-walled parts of aviation products.Kang Luo Liang Zhang Guohua Wu Wencai Liu Wenjiang Ding 2019Journal of Magnesium and Alloys2019,7,2:20
13Characterizations and mechanical properties of impregnated diamond segment using Cu-Fe-Co metal matrix显示文摘Diamond impregnated Cu-Fe-Co based saw-blade segments are directly processed by vacuum and pressure-assisted sintering at different temperature,with the purpose of reducing the cobalt content in diamond tools.Copper and iron are used as the bonding elements and co-balt-chrome pre-alloyed powder is used as the hardening phase.Effects of sintering temperature on microstructures and mechanical properties of the sintered matrix and diamond graphitization were investigated by X-ray diffraction analysis,electron probe micro-analyzer,universal testing machine,digital Rockwell hardness tester and Raman scattering analyzer.Results showed that microstructures of the sintered matrix were refined and porosities in the sintered matrix were closed to a more spherical-like shape with the increase of the sintering temperature.Densification,hardness and tensile strength of the matrix sintered at 820 ℃ were 12.75%,2.72% and 156.38% higher than that of the matrix sintered at 740 ℃,respectively.Diamond graphitization was not occurred at 820 ℃.The hardness and the tensile strength rose 32.8% and 13.5%,respectively,after 7.5 h ageing treatment.The matrix densification ascent and the dispersed distribution of Co-Cr pre-alloyed powders contributed a hardness improvement and a tensile strength improvement to the Cu-Fe based matrix.Li, Wensheng Zhang, Jie Wang, Shucai Dong, Hongfeng Li, Yaming Liu, Yi 2012Rare Metals2012,31,1:19
14A review on thermal conductivity of magnesium and its alloys显示文摘This review summarizes recent researching works the thermal conductivity of Mg–Zn,Mg–Al,Mg–Mn and Mg–RE alloys.Solute atoms,heat treatment,deformation and temperature,which have significant influence on the thermal conductivity of magnesium alloys,are highlighted.For an individual solute atom,its effects on thermal conductivity are highly dependent on its chemical valence,radius and extra-nuclear electrons.The thermal conductivity of Mg alloys is decreased by solution treatment,but improved by aging and/or annealing treatments.As for the deformed Mg alloys,the thermal conductivity along transverse or normal direction is superior to that of along extrusion or rolling direction.We expect this review is helpful for those who are working on developing Mg alloys with superior thermal conductivity.©2020 Published by Elsevier B.V.on behalf of Chongqing University.Shubo Li Xinyu Yang Jiangtao Hou Wenbo Du 2020Journal of Magnesium and Alloys2020,8,1:18
15Effect mechanisms of micro-alloying element La on microstructure and mechanical properties of hypoeutectic Al-Si alloys显示文摘The rare earth influence on the as-cast micro structures and mechanical properties of aluminum alloys attracted great attentions in the last decades.But up to date no reports can be found on the effect of microalloying element La(La addition is below 0.1 wt.%) on the solidification of hypoeutectic Al-Si alloys.This study carried out solidification experiments with Al-6 Si alloys micro-alloyed by element La.The α-Al grain refinement,the eutectic Si modification and the tensile properties improvement caused by microalloying element La were investigated.The effect mechanisms of La were discussed.It is demonstrated that the addition of La as low as 100 ppm can deprave the more effective heterogeneous nucleation conditions for the eutectic Si caused by the impurity P.The addition of 0.06 wt.% La is sufficient to achieve an ideal α-Al grain refinement,eutectic Si modification and ductility improvement of the alloys.LaAlSi phase forms in the Al-Si alloy with the additive amount of La higher than 0.06 wt.%.It has a tetragonal structure.Micro-alloying element La refines the α-Al grains by working as a surfactant and modifies the eutectic Si by promoting the formation of the significant multiple Si twins.Qiuju Zheng Lili Zhang Hongxiang Jiang Jiuzhou Zhao Jie He 2020Journal of Materials Science & Technology2020,47,12:18
16Quantitative approach on SEM images of microstructure of clay soils显示文摘The working principles of Videolab Image Processing System (VIPS), the examining methods of orientation of microstructural units of clay soils and analysing results on SEM images of some typical microstructures of clay soils using the VIPS are introduced.施斌 李生林 M.Tolkachev 1995Science China Chemistry1995,38,6:18
17Effects of temperature on the tribological behavior of Al0.25CoCrFeNi high-entropy alloy显示文摘The tribological behavior of Al0.25 CoCrFeNi high-entropy alloy(HEA) sliding against Si3N4 ball was investigated from room temperature to 600°. The microstructure of the alloys was characterized by simple FCC phase with 260 HV. Below 300°, with increasing temperature, the wear rate increased due to high temperature softening. The wear rate remained stabilized above 300°due to the anti-wear effect of the oxidation film on the contact interface. The dominant wear mechanism of HEA changed from abrasive wear at room temperature to delamination wear at 200°, then delamination wear and oxidative wear at 300°and became oxidative above 300°. Moreover, the adhesive wear existed concomitantly below 300°.L.M.Du L.W.Lan S.Zhu H.J.Yang X.H.Shi P.K.Liaw J.W.Qiao 2019Journal of Materials Science & Technology2019,35,5:17
18合金元素、加工与热处理对新型近β型钛合金TiZrMoNb力学性能的影响及微观分析显示文摘系统研究了不同合金添加元素(Mo、Zr、Nb)、加工及热处理对近β型医用钛合金力学性能和显微组织的影响规律,讨论保持医用钛合金生物力学相容性匹配的影响因素和方法。研究发现:TiNbZrMo合金中增加Zr、Mo元素含量使合金强化,而增加Mo、Nb元素含量和热加工率利于降低弹性模量。经过固溶处理后强度和弹性模量降低,而时效处理后合金产生弥散强化和细晶强化使强度和弹性模量提高。新合金冷热加工性能好,无明显各向异性,经过适当热处理可以达到高强度、低弹性模量和优良的塑韧性、疲劳性能综合匹配。于振涛 张亚峰 刘辉 麻西群 余森 张明华 2010稀有金属材料与工程2010,39,10:16
19Enhanced Mechanical Properties of Friction Stir Welded 5083Al-H19 Joints with Additional Water Cooling显示文摘3-mm-thick 5083Al-H19 rolled plates were friction stir welded(FSW) at tool rotation rates of 800 and200 rpm with and without additional water cooling. With decreasing the rotation rate and applying water cooling, softening in the FSW joint was significantly reduced. At a low rotation rate of 200 rpm with additional water cooling, almost no obvious softening was observed in the FSW joint, and therefore a FSW5083Al-H19 joint with nearly equal strength to the base material(BM) was obtained. Furthermore, the grains in the nugget zone were considerably refined with reducing the heat input and ultrafine equiaxed grains of about 800 nm were obtained in the lowest heat input condition. This work provides an effective method to achieve high property FSW joints of precipitate-hardened and work-hardened Al alloys.B.B.Wang F.F.Chen F.Liu W.G.Wang P.Xue Z.Y.Ma 2017Journal of Materials Science & Technology2017,33,9:16
20New Duplex Microstructure of Grain Boundary Allotriomorphic Ferrite/Granular Bainite显示文摘As-rolled microstructure and mechanical properties of a new kind of grain boundary allotriomorphic ferrite/granular bainite duplex steel plate and its crack propagation behavior were investigated in comparison with simple granular bainitic steel plate. These new duplex plate steels possess better combination of strength and toughness than granular bainite plate steels under the conditions of conventional rolling and air-cooling. The observation of fatigue crack propagation behaviors showed that the existence of proper grain boundary allotriomorphic ferrite increases the compatible deformation ability of duplex microstructure and leads to the formation of crack branching and curving route, and it has an evidently blunting effect on microcrack tip and results in higher impact toughness. In addition, the new duplex steel plate also has good weldability as hot-rolled high strength low alloy structural steel.XU Ping-guang FANG Hong-sheng BAI Bing-zhe WANG Zhen-jia YANG Zhi-gang HUANG Jin-feng 2002Journal of Iron and Steel Research(International)2002,9,2:16
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