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Enhancing Fe content tolerance in A356 alloys for achieving low carbon footprint aluminum structure castings

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Journal of Materials Science & Technology 2023年第30期161卷 180-191页

作者： Guodong Niu Jianfeng Wang jinwen ye Jian Mao College of Materials Science and Engineering Sichuan UniversityChengdu 610065China China Science Lab General Motor’s Global Research and DevelopmentShanghai 201206China

Low carbon footprint aluminum structure castings are the mainstream development direction of alu-minum alloys in the *** the Fe content tolerance upper limit in casting aluminum alloys is considered an effective way to promote the application of recycled aluminum *** this work,it was found that with the Ce and TiCN NPs(nanoparticles)addition simultaneously to A356 alloys,the acicular Fe-rich phases(β-Al 5 FeSi)which damages the properties can be changed into beneficial phases(core-shell heterostructures)for the alloy,and hence the mechanical properties of A356 alloys can be *** TiCN nanoparticles and rare element Ce play crucial roles in the formation of core-shell *** formation mechanism of core-shell heterostructure was also systematically researched from the perspective of thermodynamics and *** study provides a simple and feasible strategy to eliminate the harmful effects of Fe impurity and contributes to the industrialization of low carbon footprint aluminum structure castings.

关键词： A356 casting aluminum alloys Heterostructure Carbon neutral TiCN nano particles Mechanical properties

Effect of(Cr,V)_(2)(C,N)on the Microstructure and Mechanical Properties of WC-10Co Cemented Carbides

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Journal of Wuhan University of Technology(Materials Science) 2024年第5期39卷 1138-1148页

作者： LI Xiangkun WANG Lu ye jinwen School of Materials Science and Engineering Sichuan UniversityChengdu 610065China

WC-10Co cemented carbides with finer WC and narrower grain size distributions are produced by using(Cr,V)_(2)(C,N)as grain growth *** a result,with the increase of(Cr_(0.9),V_(0.1))_(2)(C,N)and(V_(0.9),Cr_(0.1))_(2)(C,N),the grains size of WC and mean free path of Co phase decrease,and adjacency of WC *** and homogenization of grains enhance the transverse rupture strength(TRS)and the ***,the deflection and bridging of cracks keep the fracture toughness at a respectable *** WC-10Co-0.6(Cr_(0.9),V_(0.1))_(2)(C,N)-0.025(V_(0.9),Cr_(0.1))_(2)(C,N)cemented carbides exhibit excellent comprehensive mechanical properties with the TRS of 4602.6 MPa,hardness of 1835 kg/mm^(2),and fracture toughness of 10.39 MPa·m^(1/2),***,the large pores are caused by excess N larger than 0.03 wt%and deteriorates the mechanical *** provide a new approach to WC-Co cemented carbides preparation with a narrow grain size distribution by adding novel grain growth inhibitors.

关键词： (Cr,V)_(2)(C,N) nutrient content WC grains size microstructure mechanical properties

Improvement of mechanical properties and investigation of strengthening mechanisms on the Ti_(3)AlC_(2) ceramic with nanosized WC addition

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Journal of Advanced Ceramics 2024年第6期13卷 861-876页

作者： Yi Zhong Ying Liu Qinkai Jiang Na Jin Zifeng Lin jinwen ye School of Materials Science&Engineering Sichuan UniversityChengdu 610065China Yibin R&D Park Yibin Industrial Technology Research InstituteSichuan UniversityYibin 644005China

Ti_(3)AlC_(2) (TAC) has great potential for use as an ablation material in aerospace applications due to its great oxidation/ablation resistance, but its high-temperature strength and thermal shock resistance still have much room for simultaneous improvement under fast temperature variation conditions. Herein, we used Ti_(3)AlC_(2) and WC powders as raw materials and successfully fabricated textured (Ti,W)_(3)AlC_(2) ceramic with small amounts of TiC and Al_(2)O_(3), and room temperature mechanical properties such as flexural strength (1146±46.9 MPa), fracture toughness (11.78±0.44 MPa·m^(1/2)), and hardness (5.81±0.11 GPa) at 5 wt% WC addition were achieved. The high-temperature strength of the ceramic was significantly improved, and better thermal shock resistance from 298 to 1173 K was simultaneously acquired together with the regulation of the elastic modulus, thermal conductivity, and thermal expansion coefficient, providing (Ti,W)_(3)AlC_(2) with more possibilities for fast-temperature variation applications. Strengthening and toughening mechanisms were proposed. Scanning transmission electron microscopy high-angle annular dark-field imaging (STEM-HADDF) showed that W randomly replaced the Ti1 and Ti2 sites of Ti_(3)AlC_(2), providing a good reference for establishing crystal models, and further density functional theory (DFT) calculations based on these models indicated a higher fracture energy of (Ti,W)_(3)AlC_(2) along different crystal planes, providing superior resistance to transgranular fracture;a lower mismatch degree of (Ti,W)_(3)AlC_(2)/Al_(2)O_(3) resulted in stronger interface bonding, resulting in greater resistance to intergranular fracture as well as more balanced stress distributions at different interfaces.

关键词： mechanical properties solid solution MAX phase transmission electron microscopy(TEM) ceramic atomic structure

Preparation of isotropic Sm_(2)Fe_(17)N_(x) magnetic powders and their bonded magnets

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Rare Metals 2006年第Z1期25卷 568-571页

作者： ye jinwen LIU Ying LI Meng SONG Dayu GAO Shengji TU Mingjing College of Material Science and Engineering Sichuan UniversityChengdu 610065China

The isotropic Sm_(2)Fe_(17)N_(x)magnetic powders were prepared by Hydrogenation-Disproportion-Desorption-Recombination(HDDR)*** phase and microstructure evolutionary process of Sm-Fe alloy during the solidification,homogenization,HDDR and nitration processes were investigated by means of XRD,SEM,EDX and *** results show that the homogeneous Sm_(2)Fe_(17)alloy was successfully obtained and the impurity phases and residual stress were well removed by heated at 1050℃for 24 *** heated at 800℃for 1h in H_(2)of 0.1 MPa,the alloy turns into SmHx andα-Fe with plenty of *** vacuumized at 800℃for 2 h the alloy recombines into Sm_(2)Fe_(17)with a crystal grain size of about 85 *** lattice constant of the alloy increases and the expanding of the crystal cell reaches 6.28%after nitrified at 500℃for 5 *** magnetic property of isotropic bonded Sm_(2)Fe_(17)N_(x)magnets is B_(r)=0.6704 T,H_(cj)=1015 kA·m^(-1),(BH)_(max)=73.7 kJ·m^(-3)with a density of 6.04 g·cm^(-3).

关键词： rare earths permanent magnets SmFeN

基于TiCN和(Ti,W,Ta)CN的混芯结构金属陶瓷冶金过程中物相、组织结构及力学性能演变（英文）

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稀有金属材料与工程 2018年第5期47卷 1385-1392页

作者：王杰刘颖叶金文四川大学四川成都610065 教育部先进特种材料及制备加工技术重点实验室四川成都610065

研究了基于TiCN和(Ti,W,Ta)CN的混芯结构金属陶瓷冶金过程中的物相、组织结构和力学性能。通过X射线衍射(XRD)和扫描电子显微镜(SEM)等分析手段,研究了"混芯结构"金属陶瓷的冶金行为,其大致可以分为3个阶段:(Ⅰ)前致密化阶段,烧结温度低... 详细信息

研究了基于TiCN和(Ti,W,Ta)CN的混芯结构金属陶瓷冶金过程中的物相、组织结构和力学性能。通过X射线衍射(XRD)和扫描电子显微镜(SEM)等分析手段,研究了"混芯结构"金属陶瓷的冶金行为,其大致可以分为3个阶段:(Ⅰ)前致密化阶段,烧结温度低于1200℃;(Ⅱ)快速致密化阶段,烧结温度在1200~1350℃;(Ⅲ)最终致密化阶段,烧结温度高于1350℃。同时,还讨论了η相在"混芯结构"金属陶瓷中的演变规律,并采用透射电子显微镜(TEM)中的X射线能量分光谱(XEDS)和选区电子衍射(SAED)等手段分析了其结构和化学成分。此外,随烧结温度增加,金属陶瓷中的环形结构会逐渐增厚,材料的力学性能呈先增加后降低的趋势。在烧结温度达到1450℃时,材料具有最大的抗弯强度;而在烧结温度为1390℃时,材料具有最大的硬度。

关键词： TiCN基金属陶瓷混芯结构金属陶瓷烧结过程 (Ti,W,Ta)CN固溶体

关于加强高校领导干部执政能力建设的若干思考

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国家教育行政学院学报 2009年第9期 20-22页

作者：叶锦文闽江学院福建福州350108

当前,高校加强执政能力建设非常迫切和必要。高校领导干部应重点加强"四种能力",即:不断提高办人民满意高等教育的能力,不断提高建设社会主义校园民主政治的能力,不断提高建设社会主义校园文化的能力,不断提高构建社会主义和谐校园的能力。

关键词：高校干部执政能力思考

Two-step Synthesis of TiC_(0.7)N_(0.3)@WC-MoC_2 Core-shell Microspheres and Fabrication of TiC_(0.7)N_(0.3)@WC-MoC_2-based Cermets by SPS

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Journal of Wuhan University of Technology(Materials Science) 2011年第4期26卷 710-714页

作者：俞海军刘颖 School of Materials Science and Engineering Sichuan University

The precursor with TiC0.7N0.3@WO3-MO3 microspheres were prepared by a novel method from the WO3-MoO3 sol dipping. Subsequently, TiC0.7N0.3@WC-MoC2 core-shell structural microspheres were successfully obtained by carburizing the precursor at 900 °C in a flowing mixture of CH4 （20 ml·min-1） and H2 （200 ml·min-1） for 2 h. Then TiC0.7N0.3@WC-MoC2-15Co cermets were prepared utilizing the core-shell powders by spark plasma sintering （SPS）. Powders of the precursors with TiC0.7N0.3@WO3-MO3 microspheres, TiC0.7N0.3@WC-MoC2 microspheres and TiC0.7N0.3@WC-MoC2-15Co cermets were characterized by scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and X-ray diffraction （XRD）. The obtained TiC0.7N0.3@WC-MoC2 microspheres have a dense WC-MoC2 coatings shell. The thickness of the shell could be easily controlled by adjusting the number of sol dipping cycles. It was found that the TiC0.7N0.3@WC-MoC2 microspheres were more beneficial to fabricate the ＂core-rim＂ structures by SPS.

关键词： core-shell structure spark plasma sintering (SPS) microstructure fabrication

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注射成形制备NdFeB粘结磁体

粉末冶金技术 2006年第4期24卷 263-266页

作者：陈一可叶金文陕西理工学院(北区)电气工程与自动化系陕西汉中723003 四川大学金属材料系成都610065

为了制备出高性价比的粘结NdFeB注射磁体,本文系统的研究了粘结剂、添加剂的含量以及磁粉装载量对注射磁体的加工性能、磁性能等的影响规律,并从微观上揭示了其机理。本文采用低成本的国产快淬钕铁硼磁粉和国产尼龙6粘结剂制备出了磁性... 详细信息

为了制备出高性价比的粘结NdFeB注射磁体,本文系统的研究了粘结剂、添加剂的含量以及磁粉装载量对注射磁体的加工性能、磁性能等的影响规律,并从微观上揭示了其机理。本文采用低成本的国产快淬钕铁硼磁粉和国产尼龙6粘结剂制备出了磁性能Br为0·5158T、Hcb为321kA/m、Hcj为730kA/m和(BH)max为40kJ/m3的注射磁体,其性能与日本Mate公司的RNI-50产品性能相当,而价格却低得多。

关键词：注射成形粘结磁体快淬磁粉稀土

Mn掺杂Mo_2FeB_2的电子结构,磁性和弹性的第一性原理研究（英文）

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计算物理 2016年第6期33卷 726-736页

作者：王斌刘颖叶金文四川大学材料科学与工程学院四川成都610065 新乡学院物理与电子工程学院河南新乡453003

用第一性原理计算(Mo,Fe,Mn)_3B_2的结构稳定性、磁性、电子结构和弹性.过程中采用了密度泛函理论和超软赝势.研究表明反铁磁性具有最低的能量,为基态.计算所得的(Mo,Mn,Fe)B_2电子态密度和布局数与Mo_2FeB_2的类似.从电子态密度和重叠... 详细信息

用第一性原理计算(Mo,Fe,Mn)_3B_2的结构稳定性、磁性、电子结构和弹性.过程中采用了密度泛函理论和超软赝势.研究表明反铁磁性具有最低的能量,为基态.计算所得的(Mo,Mn,Fe)B_2电子态密度和布局数与Mo_2FeB_2的类似.从电子态密度和重叠布局数发现,B-B和B-Mo为共价键,对剪切模量起促进作用.通过磁性分析,发现Fe和Mn原子起主要作用.然而,Mn的掺杂对硬质相Mo_2FeB_2的成键和弹性的影响微小.

关键词：密度泛函理论电子结构磁性弹性