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Journal of Materials Science & Technology 2022年第24期119卷 11-24页

作者： W.L.Wang W.Q.Liu X.Yang R.R.Xu Q.Y.Dai School of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an 710055China

A model of coupling macro finite volume method(FVM) and cellular automata(CA) is proposed in this paper to explore the columnar-to-equiaxed transition(CET) during selective laser melting(SLM) of rare earth magnesium *** into account the impact of recoil pressure and Marangoni convection on the molten pool temperature field,the grain structure is *** suggested by the simulation results,with the undissolved Zr serving as heterogeneous nucleation sites,the liquid undercooled layer under the combined action of forced cooling,the temperature gradient and the liquid solute concentration gradient leads to *** considering the dissolution of Zr in magnesium matrix,the results demonstrate that the dissolution of element Zr is effective in significantly inhibiting the growth of columnar crystals and ensuring the sufficient constitutional supercooling(CS) required for *** addition,to raise the preheating temperature contributes to enhancing the outcome of nucleation and incresing the grain *** the interdependence model(IM),with the cooling rate gradually increasing in the SLM process of magnesium alloy,the nucleation-free zone(NFZ) reduces by decreasing the solute diffusion layer in the front of the solid/liquid(SL) interface and the temperature *** reduction in temperature gradient can promote undercooling for nucleation and facilitate the development of equiaxed *** simulation results are qualitatively verified as highly consistent through experimentation.

关键词： Multi-scale simulation Columnar-to-equiaxed transition Selective laser melting rare earth magnesium alloy Constitutional supercooling

Formation mechanism of electroless plating nickel-based composite coating on highly active rare earth magnesium alloys and its corrosion resistance and adhesion performance

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Journal of Central South University 2024年第10期31卷 3517-3531页

作者： WANG Bo LI Jia-wei XIE Zhi-hui LIU Kang XU Tao YU Gang College of Chemistry and Chemical Engineering Hunan UniversityChangsha 410012China Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province China West Normal UniversityNanchong 637002China Central South University of Forestry and Technology Changsha 410004China

The process of preparing anodic oxide film containing active sites and electroless nickel plating on highly active rare earth magnesium alloy was *** formation mechanism of electroless nickel plating on active anodic oxide film and the structure and properties of the composite coating were studied by several surface and electrochemical *** results showed that Ag nanograins with an average size of 10 nm were embedded into the anodic oxide film with pores of 0.1−2μ*** nanoparticles provided a catalytic site for the deposition of Ni-B alloy,and the Ni crystal nucleus was first grown in horizontal mode and then in cylindrical *** corrosion potential of the composite coating increased by 1.37 V and the corrosion current reduced two orders of magnitude due to the subsequent deposition of Ni-P *** high corrosion resistance was attributed to the misaligning of these micro defects in the three different layers and the amorphous structure of the Ni-P alloy in the outer *** findings provide a new idea for electroless nickel plating on anodic oxide film.

关键词： rare earth magnesium alloy electroless nickel plating composite coating Ag+activation active anodic oxidation film growth mechanism

Effect of homogenization on microstructure and properties of WE91 alloys

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Journal of rare earths 2013年第8期31卷 830-836页

作者：马鸣龙张奎李永军李兴刚石国梁 State Key Laboratory for Non-ferrous Metals and Processes Beijing General Research Institute for Non-Ferrous Metals

The microstructure and properties of the Mg-9Y-1MM-0.6Zr alloy were studied by scanning electron microscopy, optical microscopy, transmission electron microscopy, hardness and tensile testing. Homogenization was confirmed, and the solidification model was established. The as-cast alloy was mainly composed of ct-Mg and eutectic structures. The suitable homogenization pa- rameters were 535℃ for 18 h. Most of the eutectic structure dissolved in this process. Only the Mg4.26Y95.74 and Mg12 （MM） phases were remained in, and only a few microstructure occurred for prolonged time. The ultimate tensile strength of the alloy increased up to 232 MPa after homogenization, but the yield strength and the elongation were almost as same as the as-cast state. In the as-cast al- loys the cracks started in the eutectic structure, and then intergranular fracture occurred, but in the homogenate alloys residual phases became the source of the cracks and then tmnscrystalline fracture took place. The most important roles of homogenization were the decomposition of the eutectic structure, furthermore the intergranular fracture turned into a transcrystalline fracture, which was one of the main reasons to increase the strength of the alloys.

关键词： rare earth magnesium alloy homogenization microstructure mechanical property

Microstructure and texture evolution of Mg–7Y–1Nd–0.5Zr alloy sheets with different rolling temperatures

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rare Metals 2020年第11期39卷 1273-1278页

作者： Jing-Bao Liu Kui Zhang Jing-Tao Han Xing-Gang Li Yong-Jun Li Ming-Long Ma Jia-Wei Yuan Guo-Liang Shi State Key Laboratory for Fabrication and Processing of Nonferrous Metals Beijing General Research Institute for Nonferrous MetalsBeijing100088China School of Materials Science and Engineering University of Science and Technology BeijingBeijing100083China

The extruded Mg-7Y-1Nd-0.5Zr(wt%)alloy were performed to the same strain hot rolling with different *** microstructure and texture evolution of the sheets were investigated by optical microscopy(OM),scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),and electron back-scattered diffraction(EBSD).The results indicate that the microstructure becomes homogeneous after hot rolling process and precipitated phase distributes at grain boundaries along rolling *** the increase in rolling temperature,the grains of sheet grow *** sheet rolling at 400℃is composed of recrystallization grains,the necklace of the precipitated phase in the grain boundaries and excessive *** structure of necklace of the precipitated phase is fcc structure with lattice constant of a=0.75 *** rolling temperatures increasing from 400 to 450℃,the content of recrystallized grains in volume fraction with relatively random orientations increases *** with the rolling process at 400℃,the amount of precipitated phases is reduced at the grain boundary,and the precipitated phase begins to appear in the grain interior when rolling at 450℃.The structure of the precipitated phase is fcc with lattice constant of a=2.22 *** recrystallization grains begin to grow in the rolling process at 500℃.The basal texture is obviously produced during the rolling process at 400 and 450℃;however,the basal texture is weak in the rolling process at 500℃.

关键词： rare earth magnesium alloy Rolling Texture Precipitated phase

Homogenization heat treatment of Mg-7.0 wt%Y-1.0 wt%Nd-0.5 wt%Zr alloy

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rare Metals 2020年第10期39卷 1196-1201页

作者： Jing-Bao Liu Kui Zhang Jing-Tao Han Xing-Gang Li Yong-Jun Li Ming-Long Ma Jia-Wei Yuan Meng Li State Key Laboratory for Fabrication and Processing of Nonferrous Metals Beijing General Research Institute for Nonferrous MetalsBeijing 100088 China School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China

The microstructures and mechanical properties of Mg-7.0 wt%Y-1.0 wt%Nd-0.5 wt%Zr magnesium alloy were investigated both in as-cast condition and after homogenization heat treatment by differential scanning calorimetry(DSC),optical microscopy(OM),X-ray diffraction(XRD),scanning electron microscopy(SEM)and hardness *** results indicate that the ascast alloy consists ofα-Mg matrix,Mg24 Y5 and Mg41 Nd5 phases,which are eutectic phases(cubic Y-rich phase).With the increase in homogenization temperature and time,the Mg24 Y5 and Mg41 Nd5 phases are completely dissolved into matrix,and only yttrium of intermetallic compounds leaves around *** homogenization heat treatment,the elements distributed uniformly and the grains grow up not obviously,only yttrium element of intermetallic compounds left around *** optimum homogenization condition is at 537℃for 16 *** mechanical properties are improved after homogenization,with tensile strength ofσb=181 MPa,yielding strength ofσ(0.2)=144 MPa and elongation ofδ=5.5%,which are better than those of as-cast alloy.

关键词： rare earth magnesium alloy Homogenization Microstructure Hardness

Effect of solidification mode on microstructure evolution and properties of magnesium alloy with long-period stacking ordered phase

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Journal of Iron and Steel Research International 2024年第5期31卷 1127-1138页

作者： Hao Li Hong-mei Chen Xu Zhang Qian-hao Zang Jing Zhang Di Feng Yan-xin Qiao Yu-hang Guo School of Materials Science and Engineering Jiangsu University of Science and TechnologyZhenjiang212100JiangsuChina School of Metallurgy and Materials Engineering Jiangsu University of Science and TechnologySuzhou215600JiangsuChina

The solidification methods of electromagnetic stirring(EMS)and non-electromagnetic stirring were employed to prepare Mg–6Gd–3Y–xZn–0.6Zr(x=1,1.5,2,3)*** evolution of alloy microstructures and the changes in properties were analyzed for different Zn *** has been observed that in alloys without electromagnetic stirring,as the Zn content increases,the alloy structure gradually *** primary second phase transitions from Mg5RE phase to long-period stacking ordered(LPSO)phase,resulting in improved hardness and *** alloys subjected to electromagnetic stirring,there is a relatively higher content of the second phase,primarily consisting of LPSO *** applying electromagnetic stirring,the quantity and the type of LPSO phase in the alloy *** alloy structure becomes more uniform with electromagnetic stirring,resulting in increased hardness and reduced hardness gradients within the *** mechanical properties of alloys with electromagnetic stirring are superior to those without electromagnetic stirring.

关键词： rare earth magnesium alloy LPSO phase Electromagnetic stirring Casting Property