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Study on in-situ WC particles/tungsten wire reinforced iron matrix composites under electromagnetic field

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China Foundry 2010年第2期7卷 157-162页

作者： Niu Libin Xu Yunhua Wu Hong College of Materials Science and Engnieering Xi ＂an University of Science and Technology Xi＇an 710055 China Institute of wear- Resistance Materials College of Mechanical and Electrical Engineering Xi ＇an University of Architecture ＆ Technology Xi ＇an 710055 China

By applying electromagnetic field to a system consisting of tungsten wires and grey cast iron melt,the grey cast iron matrix composite reinforced by either in-situ WC particles or the combination ofin-situ WC particles and the residual tungsten wire was *** means of differential thermal analysis(DTA),the pouring temperature ofiron melt was determined at 1,573 *** microstructures of the composites were analyzed by using of X-ray diffraction(XRD),scanning electron microscopy(SEM) equipped with an energy dispersive spectrum(EDS) and pin-on-disc abrasive wear *** obtained results indicated that,with the enhancing frequency of electromagnetic field,the amount ofin-situ WC particles gradually increases,leading to continuous decrease of the residual tungsten *** the electromagnetic field frequency was up to 4 kHz,tungsten wires reacted completely with carbon atoms in grey cast iron melt,forming WC *** electromagnetic field appeared to accelerate the elemental diffusion in the melt,to help relatively quick formation of a series of small FeW-C ternary zones and to improve the kinetic condition ofin-situ WC *** compared with the composite prepared without the electromagnetic field,the composite fabricated at 4 kHz presented good wear resistance.

关键词： tungsten carbide particle composite electromagnetic field in-situ synthesis grey cast iron

Effect of Heat Treatment on Microstructure and Mechanical Behavior of Cu-Bearing 316L Stainless Steel Produced by Selective Laser Melting

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Acta Metallurgica Sinica(English Letters) 2024年第1期37卷 169-180页

作者： Huan Yang Ying Liu Jianbo Jin Kunmao Li Junjie Yang Lingjian Meng Chunbo Li Wencai Zhang Shengfeng Zhou Sino-German College of Intelligent Manufacturing Shenzhen Technology UniversityShenzhen518118China Institute of Advanced wear and Corrosion Resistance and Functional Materials Jinan UniversityGuangzhou510632China Department of Orthopedics First Affiliated Hospital of Jinan UniversityGuangzhou510632China

Cu-bearing stainless steels(SSs)with high strength,excellent plasticity,and effective antimicrobial properties hold significant potential for applications in the marine *** this study,Cu-bearing SSs with copper ranging from 0 to 6.0 wt%were successfully prepared using selective laser melting(SLM)*** the Cu-bearing SSs with different copper contents,the effect of heat treatment on the microstructural and mechanical behaviors was studied *** observations revealed that the subgrain size of Cu-bearing SSs increased with heat treatment at 500℃ and 700℃ for 6 ***,the tensile strength and elongation increased after the heat treatment temperature due to the combined effect of dislocations,twins,andε-Cu precipitated ***,after heat treatment at 700℃,the SLM4.5Cu sample exhibited an abnormal rise in tensile strength and *** finding suggests that the diffusion strengthening caused byε-Cu precipitates exceeded the stacking fault ***,the tensile strength and elongation reached 693.32 MPa and 56.94%,*** work provides an efficient approach for preparing Cu-bearing SSs with exceptional strength and plasticity.

关键词： Selective laser melting Cu-bearing stainless steel(SS) Heat treatment Mechanical properties

Stress-corrosion coupled damage localization induced by secondary phases in bio-degradable Mg alloys:phase-field modeling

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Journal of Magnesium and Alloys 2024年第1期12卷 361-383页

作者： Chao Xie Shijie Bai Xiao Liu Minghua Zhang Jianke Du The Faculty of Mechanical Engineering and Mechanics Ningbo UniversityNingbo 315211P.R.China Key Laboratory of High Temperature wear Resistant Materials Preparation Technology of Hunan Province Hunan University of Science and TechnologyXiangtan 411201P.R.China

In this study,a phase-field scheme that rigorously obeys conservation laws and irreversible thermodynamics is developed for modeling stress-corrosion coupled damage(SCCD).The coupling constitutive relationships of the deformation,phase-field damage,mass transfer,and electrostatic field are derived from the entropy *** SCCD localization induced by secondary phases in Mg is numerically simulated using the implicit iterative algorithm of the self-defined finite *** quantitative evaluation of the SCCD of a C-ring is in good agreement with the experimental *** capture the damage localization,a micro-galvanic corrosion domain is defined,and the buffering effect on charge migration is *** cases are investigated to reveal the effect of localization on corrosion acceleration and provide guidance for the design for resistance to SCCD at the crystal scale.

关键词： Phase field Mg alloys Stress-corrosion coupled damage Damage localization Finite element method

The flow behavior in as-extruded AZ31 magnesium alloy under impact loading

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Journal of Magnesium and Alloys 2018年第2期6卷 180-188页

作者： Biwu Zhu Xiao Liu Chao Xie Wenhui Liu Changping Tang Liwei Lu Key Laboratory of High Temperature wear Resistant Materials Preparation Technology of Hunan Province Hunan University of Science and TechnologyXiangtan 411201China The Faculty of Mechanical Engineering and Mechanics Ningbo UniversityNingbo 315211China

As-extruded AZ31 magnesium alloy samples were compressed at ambient temperature and strain rates of 1000-3000 s^(−1).The fracture surfaces of cracked samples,the evolution of microstructures and macrotextures were *** received flow curves exhibit an abnormal behavior at strain rates above 1500 s^(−1).A strain constitutive model based on strain equivalent principle was applied to analyze the flow curves of the damaged *** results indicate that the abnormal flow behaviors of the fractured samples are related to the increasing area of crack surfaces,and kinetic energy during dynamic crack nucleation and *** initiation of the micro-crack also causes obvious flow softening in the cracked *** shapes of flow stresses of the intact samples are affected by twinning.©2018 Published by Elsevier *** behalf of Chongqing University.

关键词： Magnesium alloy Flow behavior Fracture Micro-crack Twinning.

Corrosion behavior of Al_(0.4)CoCu_(0.6)NiSi_(0.2)Ti_(0.25) high-entropy alloy coating via 3D printing laser cladding in a sulphur environment

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Journal of Materials Science & Technology 2021年第1期60卷 197-205页

作者： Hongxia Wan Dongdong Song Xiaolei Shi Yong Cai Tingting Li Changfeng Chen Beijing Key Laboratory of Failure Corrosion and Protection of Oil/Gas Facility MaterialsDepartment of Materials Science and EngineeringChina University of Petroleum(Beijing)Beijing 102249China Institute of Advanced wear&Corrosion Resistant and Functional Materials Jinan UniversityGuangzhou 510632China

High-entropy alloys(HEAs) are of great interest in materials science and engineering communities owing to their unique phase *** are constructed with five or more principal alloying elements in equimolar or near-equimolar ***,they can derive their performance from multiple principal elements ratherthan a single *** this work,three-dimensional printing laser cladding was applied to produce an Al_(0.4)CoCu_(0.6)NiSi_(0.2)Ti_(0.25) HEA *** experimental results confirmed that the laser cladding could be used to produce a thin coating of 120 μm in *** the high-temperature laser cladding process,some Fe elements diffused from the substrate to the coating,forming a combination of face-centred cubic and body-centred cubic phase *** HEA coating metallurgically bonded well with the *** to the increased dislocation density and number of grain boundaries,the HEA coating was harder and had a stronger hydrophobicity than X70 *** electrochemistry results showed that the HEA coating had better corrosion resistance than X70 *** oxides formed on the surface of the HEA coating had a certain protective ***,because of the laser cladding,the HEA coating generated *** future work,the laser cladding technology will be improved and heat treatment will be implemented to prevent formation of cracks.

关键词： High-entropy alloy coating(HEA coating) Laser cladding Corrosion behaviour

Failure analysis of ring die of a feed pellet machine

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China Foundry 2020年第2期17卷 167-172页

作者： He-da Bai Bao-chao Zheng Wei Li Xiao-hui Tu School of Comprehensive Foundation Studies and Applied Statistics Zhuhai College of Jilin UniversityZhuhai 519041GuangdongChina Institute of Advanced wear&Corrosion Resistant and Functional Materials Jinan UniversityGuangzhou 510632China

The severely worn position and failure mechanisms of the ring die of a feed pellet machine were *** macroscopic and microscopic morphologies of the failed surface,the chemical composition and mechanical properties of the collected samples were analyzed using scanning electron microscopy,energy disperse spectroscopy,optical emission spectrometry,and a universal testing *** show that the dip angle at the entrance of the ring die hole between the roller and ring die was severely *** feed powder could not be fully extruded through the dip angle at the entrance of the ring die holes,thus the density of the feed particles produced could not meet the ***,abrasive wear under high stress is the main reason of failure at the entrance of the ring die holes under the action of feeding powder;and cutting and fatigue spalling lead to substantial material *** addition,a high damp-heat environment aggravates abrasive wear on the die hole internal surface.

关键词： ring die failure analysis micro-cutting wear fatigueexfoliative wear electrochemical corrosion

OPTIMAL PERFORMANCE CHARACTERISTICS OF MORTAR INCORPORATING PHASE CHANGE MATERIALS AND SILICA FUME

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Journal of Green Building 2017年第2期12卷 59-78页

作者： Alan Richardson Ashraf Heniegal Jess Tindall Department of Mechanical and Construction Engineering Faculty of Engineering and EnvironmentNorthumbria UniversityTyne&WearUK NE18ST Department of Civil Constructions Department Faculty of Industrial EducationSuez UniversityEgypt 不详

This paper examines the thermal performance of 20 different mortar mixes,which were prepared in order to study the behaviour of mortar incorporating Phase Change Materials(PCM).The PCM was used at a rate of 10,20 and 30%by weight of total solid *** fume was added to the mixes by 10,20,30 and 50%by weight of cement to enhance the mortar *** which incorporate phase-change materials(PCM)have the capability to help regulate the temperature inside buildings,contributing to the thermal comfort while decreasing the amount of mechanical heating and cooling energy required,therefore they have the potential to reduce building carbon *** mechanical characteristics and physical properties of the mortar with PCM were *** results show that mortar with Phase Change Materials up to PCM20%can be used with an optimal compressive *** fume(SF),up to a 20%SF addition,enhanced the mechanical properties of the mortar.

关键词： phase change material mortar silica fume thermal conductivity

Unveiling the underlying mechanism of forming edge cracks upon high strain-rate rolling of magnesium alloy

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Journal of Materials Science & Technology 2020年第15期47卷 59-65页

作者： Biwu Zhu Xiao Liu Chao Xie Jing Su Pengcheng Guo Changping Tang Wenhui Liu Key Laboratory of High Temperature wear Resistant Materials Preparation Technology of Hunan Province Hunan University of Science and TechnologyXiangtan 411201China Faculty of Mechanical Engineering and Mechanics Ningbo UniversityNingbo 315211China Max-Planck-Institut für Eisenforschung GmbH Max-Planck-Strafie 1Dusseldorf40237Germany College of Mechanical and Electrical Engineering Central South University of Forestry and TechnologyChangsha 410004China Key Laboratory of High Temperature wear Resistant Materials Preparation Technology of Hunan Province Hunan University of Science and TechnologyXiangtan 477207China

In the current study,high strain-rate rolling(≥10 s-1) has been successfully employed to produce Mg-3 A1-1 Zn alloy sheets to a high reduction of 82% with a fine grain structure in a single *** underlying mechanism of forming primary and secondary edge cracks has been *** is found that dynamic recrystallization(DRX) induced by subgrains tends to blunt cracks,while twinning-induced D RX is mainly observed around sharp crack *** motion of emitted dislocations from blunted cracks is inhibited by the DRX grain ***,on one hand,increases local work hardening,and on the other hand,causes stress concentration alo ng grain boundaries especially in the triple junctions leading to the formation of secondary cracks.

关键词： Edge crack Secondary crack High strain-rate rolling AZ31 magnesium alloy Dynamic recrystallization

Controlled preparation and self-assembly of NdVO_4 nanocrystals

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Journal of Rare Earths 2018年第2期36卷 179-183页

作者： Li Tian Yan Li Huifeng Wang Shanmin Chen Jinjing Wang Zhen Guo Qiang Liu Qi Luo Yingjie Li Fafa Wu School of Materials Science and Engineering Hunan Provincial Key Defense Laboratory of High Temperature Wear-resisting Materials and Preparation Technology Hunan University of Science and Technology State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of Sciences

Phase-pure t-NdVO_4 nanocrystals with different shapes have been synthesized by facile and repeatable hydrothermal methods. The as-synthesized t-NdVO_4 nanoparticles were characterized by various techniques of X-ray diffraction（XRD）. scanning electron microscope（SEM） and transmission electron microscope（TEM）. The growth process and assembly behavior of t-NdVO_4 nanorod arrays were investigated. The results show that the morphology of t-NdV04 nanocrystals is greatly related to the pH value of precursor solution and that strong basic solution is not in favor of the formation of t-NdVO_4 nanoparticles. Due to the strong adhesive action and stabilization of OH^-ions to some crystal faces of NdVO_4, neodymium vanadate crystallite grows into oriented short nanorods and then into nanorod arrays. The shape, crystalline and dimension of NdVO_4 nanocrystals can be effectively governed in our work.

关键词： Inorganic compounds Nanostructures Chemical synthesis X-ray diffraction Rare earths