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Rare Metals 2024年第4期43卷 1786-1792页

作者： Yuan-Feng Xie Xing-Cheng Xie Zhong-Wu Li Rui-Jun Cao Zhong-Kun Lin Qing Li Chen-Guang Lin Powder metallurgy and Special Materials Research department General Research Institute for Nonferrous Metals

The effects of cryogenic treatment（CT） and tempering-cryogenic treatment（TCT） on the microstructure and properties of coarse-grained WC-10Co cemented carbides with different carbon contents were researched.The binder phase,WC mean grain sizes,W solubility in the binder,relative magnetic s aturation,densities,hardness,wear resistance and second phase precipitation of cemented carbides with different heat treatments were discussed.The results show that there are significant changes of microstructure and properties in the samples with CT and TCT,especially due to the precipitation of metastable nanoparticles WxCoyCzin the binder during the heat treatments of CT and TCT.With the simultaneous combination of microstructure and nanoparticle-reinforced binder,a dramatically improved combination of hardness and wear resistance of the samples after TCT has been achieved.

关键词： Cryogenic treatment Tempering Coarse-grained cemented carbide Carbon content Nanoparticle-reinforced binder

Effect of solidification cooling rate on microstructure and tribology characteristics of Zn-4Si alloy

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International Journal of Minerals,metallurgy and Materials 2024年第2期31卷 362-373页

作者： F.Akbari M.Golkaram S.Beyrami G.Shirazi K.Mantashloo R.Taghiabadi M.Saghafi Yazdi I.Ansarian department of metallurgy and Material Science Imam Khomeini International University(IKIU)Qazvin ***Iran

The main objective of this work was to modify the microstructure and enhance the tribological properties of a new Zn-4Si al-loy through a high solidification cooling rate(SCR).According to the results,by increasing the SCR from 2.0 to 59.5℃/s the average size of primary Si particles and that of the grains reduced from 76.1 and 3780μm to less than about 14.6 and 460μm,respectively.Augment-ing the SCR also enhanced the microstructural homogeneity,decreased the porosity content(by 50%),and increased the matrix hardness(by 36%).These microstructural changes enhanced the tribological behavior.For instance,under the applied pressure of 0.5 MPa,an in-crease in the SCR from 2.0 to 59.5℃/s decreased the wear rate and the average friction coefficient of the alloy by 57%and 23%,respect-ively.The wear mechanism was also changed from the severe delamination,adhesion,and abrasion in the slowly-cooled alloy to the mild tribolayer delamination/abrasion in the high-cooling-rate-solidified sample.

关键词： zinc-silicon alloy primary silicon solidification cooling rate tribology sliding wear

Predicting grain size-dependent superplastic properties in friction stir processed ZK30 magnesium alloy with machine learning methods

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Journal of Magnesium and Alloys 2024年第5期12卷 1931-1943页

作者： Farid Bahari-Sambran Fernando Carre?o C.M.Cepeda-Jiménez Alberto Orozco-Caballero Physical metallurgy department CENIM-CSIC department of Mechanical Engineering Chemistry and Industrial Design Polytechnic University of Madrid

The aim of this work is to predict, for the first time, the high temperature flow stress dependency with the grain size and the underlaid deformation mechanism using two machine learning models, random forest（RF） and artificial neural network（ANN）. With that purpose, a ZK30 magnesium alloy was friction stir processed（FSP） using three different severe conditions to obtain fine grain microstructures（with average grain sizes between 2 and 3 μm） prone to extensive superplastic response. The three friction stir processed samples clearly deformed by grain boundary sliding（GBS） deformation mechanism at high temperatures. The maximum elongations to failure, well over 400% at high strain rate of 10-2s-1, were reached at 400 ℃ in the material with coarsest grain size of 2.8 μm, and at 300 ℃ for the finest grain size of 2 μm. Nevertheless, the superplastic response decreased at 350 ℃ and 400 ℃ due to thermal instabilities and grain coarsening, which makes it difficult to assess the operative deformation mechanism at such temperatures. This work highlights that the machine learning models considered, especially the ANN model with higher accuracy in predicting flow stress values, allow determining adequately the superplastic creep behavior including other possible grain size scenarios.

关键词： Machine learning Artificial intelligence Magnesium alloys Superplasticity Friction stir processing Grain coarsening

Challenges and opportunities in the production of magnesium parts by directed energy deposition processes

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Journal of Magnesium and Alloys 2024年第5期12卷 1663-1686页

作者： Gürel ?am Ali Günen Iskenderun Technical University Faculty of Engineering and Natural Sciences Department of Mechanical Engineering Iskenderun Technical University Faculty of Engineering and Natural Sciences Department of Metallurgy and Materials Engineering

Mg-alloys have gained considerable attention in recent years for their outstanding properties such as lightweight, high specific strength,and corrosion resistance, making them attractive for applications in medical, aerospace, automotive, and other transport industries. However,their widespread application is hindered by their low formability at room temperature due to limited slip systems. Cast Mg-alloys have low mechanical properties due to the presence of casting defects such as porosity and anisotropy in addition to the high scrap. While casting methods benefit from established process optimization techniques for these problems, additive manufacturing methods are increasingly replacing casting methods in Mg alloys as they provide more precise control over the microstructure and allow specific grain orientations,potentially enabling easier optimization of anisotropy properties in certain applications.Although metal additive manufacturing(MAM) technology also results in some manufacturing defects such as inhomogeneous microstructural evolution and porosity and additively manufactured Mg alloy parts exhibit lower properties than the wrought parts, they in general exhibit superior properties than the cast counterparts. Thus, MAM is a promising technique to produce Mg alloy parts. Directed energy deposition processes, particularly wire arc directed energy deposition(WA-DED), have emerged as an advantageous additive manufacturing(AM) technique for metallic materials including magnesium alloys, offering advantages such as high deposition rates, improved material efficiency, and reduced production costs compared to subtractive processes. However, the inherent challenges associated with magnesium,such as its high reactivity and susceptibility to oxidation, pose unique hurdles in the application of this technology.This review paper delves into the progress made in the application of DED technology to Mg-alloys, its challenges, and prospects.Furthermore, the predominant imperfections, notably inhomogeneous microstructur

关键词： Additive manufacturing DED processes Arc-DED Wire arc additive manufacturing (WAAM) 3-D printing High deposition rate

Crystal engineering regulation achieving inverse temperature symmetry breaking ferroelasticity in a cationic displacement type hybrid perovskite system

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Chinese Chemical Letters 2024年第5期35卷 477-481页

作者： Na Wang Wang Luo Huaiyi Shen Huakai Li Zejiang Xu Zhiyuan Yue Chao Shi Hengyun Ye Leping Miao Chaotic Matter Science Research Center Department of MaterialsMetallurgy and ChemistryJiangxi University of Science and TechnologyGanzhou 341000China

Ferroelastic hybrid perovskite materials have been revealed the significance in the applications of switches,sensors,actuators,etc.However,it remains a challenge to design high-temperature ferroelastic to meet the requirements for the practical applications.Herein,we reported an one-dimensional organicinorganic hybrid perovskites(OIHP)(3-methylpyrazolium)CdCl_(3)(3-MBCC),which possesses a mmmF2/m ferroelastic phase transition at 263 K.Moreover,utilizing crystal engineering,we replace-CH_(3) with-NH_(2) and-H,which increases the intermolecular force between organic cations and inorganic frameworks.The phase transition temperature of(3-aminopyrazolium)CdCl_(3)(3-ABCC),and(pyrazolium)CdCl_(3)(BCC)increased by 73 K and 10 K,respectively.Particularly,BCC undergoes an unconventional inverse temperature symmetry breaking(ISTB)ferroelastic phase transition around 273 K.Differently,it transforms from a high symmetry low-temperature paraelastic phase(point group 2/m)to a low symmetry high-temperature ferroelastic phase(point group ī)originating from the rare mechanism of displacement of organic cations phase transition.It means that crystal BCC retains in ferroelastic phase above 273 K until melting point(446 K).Furthermore,characteristic ferroelastic domain patterns on crystal BCC are confirmed with polarized optical microscopy.Our study enriches the molecular mechanism of ferroelastics in the family of organic-inorganic hybrids and opens up a new avenue for exploring high-temperature ferroic materials.

关键词： Organic-inorganic hybrid perovskite Crystal engineering Inverse temperature symmetry breaking Displacement type phase transition Ferroelasticity

Ferrite features in simulated transition zone of EH36 shipbuilding steel submerged arc welded by CaF_(2)-SiO_(2)-MnO fluxes

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Journal of Iron and Steel Research(International) 2024年第4期31卷 790-796页

作者： Ming Zhong Dong Hu Da-ming Guo Somnath Basu Cong Wang Key Laboratory for Ecological metallurgy of Multimetallic Mineral(Ministry of Education) Northeastern UniversityShenyang 110819LiaoningChina School of metallurgy Northeastern UniversityShenyang 110819LiaoningChina The State Key Laboratory of Refractories and metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina department of Metallurgical Engineering and Materials Science Indian Institute of Technology BombayMumbai 400076MaharashtraIndia

Ferrite features in the simulated transition zone welded with CaF_(2)-SiO_(2)-MnO fluxes containing various MnO contents have been investigated.Confocal laser scanning microscopy has been applied to simulate the thermal cycling of the transition zone and the phase transformations during cooling have been in-situ observed.It has been found that the appearance temperature for ferrite side plate decreases with increasing Mn content in the weld metals caused by MnO content increasing.Meanwhile,growth rates for both ferrite side plate and acicular ferrite are significantly enhanced with a higher Mn content of weld metal.Furthermore,from the statistical fractions of salient microstructures,for all samples,the acicular ferrite,grain boundary ferrite,and polygonal ferrite take over more than 90%.It has also been demonstrated that with the increase in Mn content,the ferrite side plate fraction increases slightly from 5%to 10%and the acicular ferrite fraction shows a tendency of first increasing and then decreasing,which experiences the maximum with the flux containing 30 wt.%MnO.This phenomenon is believed to be controlled by the O and Mn contents in weld metals synergistically.

关键词： Submerged arc welding Transition zone Phase transformation Microstructure

Cerium oxide inclusion nucleation mechanism based on classical nucleation theory and two-step nucleation

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Journal of Rare Earths 2024年第4期42卷 793-802页

作者： Yutang Li Jun Wang Linzhu Wang Chaoyi Chen Shufeng Yang Junqi Li Xiang Li School of Materials and metallurgy Guizhou UniversityGuiyang550025China State Key Laboratory of Public Big Data Guizhou UniversityGuiyang550025China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing100083China department of Materials&metallurgy Engineering Guizhou Institute of TechnologyGuiyang550003China

It is challenging to assess the mechanism responsible for the nucleation of inclusions in metals at high temperatures.The present work therefore systematically investigates the nucleation of cerium oxide inclusions according to classical nucleation theory and a two-step nucleation mechanism.The nucleation rates and nucleation radii of these inclusions are obtained,and the results demonstrate a considerable difference between theoretical and experimental values.On the basis of a two-step nucleation mechanism,(CeO_(2))_(n) and(Ce_(2)O_(3))_(n)(n=1-6)clusters were constructed and the thermodynamic properties of both these clusters and of cerium oxide nanoparticles were analyzed.In addition,the entropies and heat capacity changes of cerium oxides were determined using first principles calculations and are found to be consistent with literature data.The present data indicate that the cerium oxide inclusion nucleation pathway can be summarized as[Ce]+[O]→(CeO_(2))n/(Ce_(2)O_(3))_(n)→(Ce_(2)O_(3))_(n)→(Ce_(2)O_(3))_(2)→core(Ce_(2)O_(3)crystal)-shell((Ce_(2)O_(3))_(2) cluster)nanoparticles→(Ce_(2)O_(3))bulk.

关键词： Cerium oxide inclusion Classical nucleation theory Two-step nucleation mechanism First principles Rare earths

Revealing the stability origins of 596 days-humidity-stable semitransparentperovskite solar cells

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Journal of Energy Chemistry 2024年第7期94卷 208-216页

作者： Tian Chen Ying Yang Congtan Zhu Weihuang Lin Qilin Dai Xueyi Guo School of metallurgy and Environment Central South UniversityChangsha 410083HunanChina department of Chemistry Physics and Atmospheric SciencesJackson State UniversityJacksonMS 39217USA

Hybrid organic-inorganic perovskites(HOIPs)hold promise in the field of optoelectronics due to their excellent photoelectric conversion efficiency.However,the ion migration and hygroscopicity of these perovskite solar cells need to be addressed.Here,we presented semitransparent perovskite solar cells(ST-PSCs)using hole transport layer(HTL)combined with polyaniline(PANI)to stabilize HTL/perovskite interface,achieving a humidity durability(RH,50%-90%)for 596 days(14304 h)without encapsulation.Moreover,the decrease in hydrolysis products(LiF)showed the interaction between PANI with the addi-tives in HTL dramatically inhibited the water uptake and corrosion on MAPbI_(3),layer.The PANI modified samples had a higher I/Pb ratio and lower trap state density,which indicated the passivation effect of PANI on the uncoordinated Pb^(2+)and iodine vacancies.Subsequently,PANI successfully stabilized the interface and perovskite by inhibiting the formation of Pb^(0) and Au migration as long period storage.This work presented an interfacial design to develop HOiP in air with high humidity stability.

关键词： HTL/perovskite interface Polyaniline-passivation Humidity-degradation mechanism lon migration

Preface:Heavy metal(loid)s at mining&metallurgical sites:Fate,risk and remediation

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Journal of Central South University 2024年第4期31卷 1033-1035页

作者：薛生国李楚璇赵东叶吴川 School of metallurgy and Environment Central South UniversityChangsha 410083China department of Civil Constructionand Environmental EngineeringSan Diego State UniversitySan DiegoCA 92182USA

The contamination of heavy metal(loid)s at mining&metallurgical sites has been a major environmental challenge worldwide[1].Typically,large amounts of metal(loid)s-bearing wastes are generated at these sites,such as smelting slag,combustion residues,mine tailings,wastewater,and exhaust gas[2].Due to their high mobility in the environment,the released heavy metal(loid)s can easily enter the soil and water environment,posing long-term and widespread threats to ecological and human health[3].

关键词： mining wastewater smelting

Effect of MgO-Cr_(2)O_(3) and Mg0-MgAl_(2)0_(4)-based refractories on refractory-steel interface reaction and cleanliness of pipeline steel

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Journal of Iron and Steel Research(International) 2024年第4期31卷 849-860页

作者： Guang-mei Yang Cheng Yuan Chang Liu Qiang Wang Guang-qiang Li Yong-shun Zou Ao Huang The State Key Laboratory of Refractories and metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Key Laboratory for Ferrous metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan 430081HubeiChina

The interaction of MgO-MgAl_(2)O_(4)-based and MgO-Cr_(2)O_(3)-based refractories with X70 molten steel was studied by immersion experiments at 1560℃.The effects of immersion time(30 and 60 min)on the contents of total oxygen(TO),Al,Nb,Si,Mn,and Cr as well as the composition,number density,and size distribution of inclusions in the molten steel were investigated.The influence of the penetration and erosion degree of the molten steel to the refractory on the steel-refractory interface layer was analyzed.The results show that,at 1560℃,the MgO-MgAl_(2)O_(4)-based refractory can better control the contents of TO and the composition of molten steel compared with the MgO-Cr_(2)O_(3)-based refractory.The TO content is only 16×10^(-4) wt.%in the molten steel after reacted with the Mg0-MgAl_(2)O_(4)-based refractory at the end point of refining,4 accounting for 11.5%of that reacted with the MgO-Cr_(2)O_(3)-based refractory(139×10^(-4) wt.%).The number density of inclusions is only 14 mm^(-2),and the average size ofinclusions is only 1.31μm,with thelargest proportion of inclusions in 1-2μm(70%).The Al_(2)O_(3)-MnS-CaO complex inclusions in the original steel changed to complex inclusions dominated by Cr-Nb-Mn-S-O and MgO.Al_(2)O_(3),corresponding to the MgO-Cr_(2)O_(3)-based and MgO-MgAl_(2)O_(4)-based refractories,respectively.The MgO.Al_(2)O_(3) layer was formed at the reaction interface between MgO-MgAl_(2)O_(4)-based refractory and molten steel,which is helpful to restrict the erosion of refractories and the pollution of molten steel.The damage mechanism of the MgO-Cr_(2)O_(3)-based refractory is mainly permeation and chemical reaction,while the damage of the MgO-MgAl_(2)O_(4)-based refractory is mainlyscouring erosion.

关键词： MgO-Cr_(2)O_(3)-based refractory MgO-MgAl O_(4)-based refractory Nonmetallic inclusion Erosion interface layer Steel penetration