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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

(Cr,La)_(2)(C,N)添加对Ti(C,N)基金属陶瓷结构与性能的影响

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粉末冶金技术 2024年第1期42卷 45-52页

作者：龙航飞叶金文曹之南四川大学材料科学与工程学院成都610064

在开放体系下采用高温碳管炉制备了(Cr,La)_(2)(C,N)粉末,并将其作为添加剂制备Ti(C,N)基金属陶瓷。利用X射线衍射仪、扫描电镜、万能力学试验机及维氏硬度计等设备研究了(Cr,La)_(2)(C,N)添加对Ti(C,N)基金属陶瓷微观组织和力学性能的... 详细信息

在开放体系下采用高温碳管炉制备了(Cr,La)_(2)(C,N)粉末,并将其作为添加剂制备Ti(C,N)基金属陶瓷。利用X射线衍射仪、扫描电镜、万能力学试验机及维氏硬度计等设备研究了(Cr,La)_(2)(C,N)添加对Ti(C,N)基金属陶瓷微观组织和力学性能的影响。结果表明,(Cr,La)_(2)(C,N)的添加能够有效细化Ti(C,N)基金属陶瓷的硬质相晶粒,其中Cr、La元素主要固溶于粘结相,La元素促进了硬质相的溶解–析出过程,金属陶瓷的抗弯强度、硬度以及断裂韧性等力学性能得到明显改善。当添加(Cr,La)_(2)(C,N)的质量分数为5.0%时,Ti(C,N)基金属陶瓷的综合力学性能达到最佳,抗弯强度为2002 MPa,维氏硬度为1643 MPa,断裂韧性为11.22 MPa·m^(1/2)。

关键词： Ti(C,N)基金属陶瓷 (Cr,La)_(2)(C,N) 微观组织力学性能断裂韧性

(Cr_(0.87),V_(0.13))_(2)(C,N)含量对WC-10Co硬质合金微观组织及力学性能的影响

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工具技术 2024年第6期58卷 50-55页

作者：李祥坤王璐叶金文四川大学材料科学与工程学院

通过添加一种新型抑制剂(Cr_(0.87),V_(0.13))_(2)(C,N)制备出室温和高温下均性能优异的WC-10Co硬质合金,并研究(Cr_(0.87),V_(0.13))_(2)(C,N)含量对WC-10Co硬质合金微观组织、室温力学性能和高温硬度的影响。结果表明,添加(Cr_(0.87),V_(0.13))_(2)(C,N)具有良好的细化WC晶粒的效果,随着(Cr_(0.87),V_(0.13))_(2)(C,N)含量增加,WC晶粒不断细化,硬度逐渐增加,断裂韧性降低,抗弯强度(TRS)先升高后降低,当(Cr_(0.87),V_(0.13))_(2)(C,N)的添加量为0.6wt.%时,抗弯强度最高为3840.5MPa。抑制剂(Cr_(0.87),V_(0.13))_(2)(C,N)的加入对高温硬度具有积极影响,随着(Cr_(0.87),V_(0.13))_(2)(C,N)含量增加,高温硬度逐渐增加;当(Cr_(0.87),V_(0.13))_(2)(C,N)含量不变时,随着温度升高,硬度逐渐降低。

关键词： (Cr_(0.87),V_(0.13))_(2)(C,N) 微观组织室温力学性能高温硬度

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

“厚基础、强实践、重创新”的材料类本科专业人才培养模式重构与实践

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工程科学与技术 2024年第2期56卷 17-23页

作者：杨劼人叶金文苟倩王泽高吴朝玲朱建国张云刘颖四川大学材料科学与工程学院四川成都610065

材料科学与工程是国家“四个面向”的重要支撑,先进材料及制造是国家战略性、基础性产业,是涉及国家安全的关键核心领域。本文针对国家对材料类高素质人才的迫切需求和传统材料类本科人才培养中存在的专业过度细分、实践能力偏弱、创新... 详细信息

材料科学与工程是国家“四个面向”的重要支撑,先进材料及制造是国家战略性、基础性产业,是涉及国家安全的关键核心领域。本文针对国家对材料类高素质人才的迫切需求和传统材料类本科人才培养中存在的专业过度细分、实践能力偏弱、创新能力不足等局限性问题,从一流高等院校本科生培养视角出发,依托四川大学厚重基础与综合优势,结合近二十年来材料科学与工程学院本科育人改革实践,系统阐释了“厚基础、强实践、重创新”的材料类本科人才培养特色与新模式。全文宗旨在于论述如何发挥“材料科学与工程”世界一流学科建设学科、一级学科国家重点学科的优势,服务国家重大需求和国民经济主战场,全面总结了系统性多层次育人探索和教学改革,对培养理想坚定、基础扎实、勇于创新的材料类优秀本科人才的具体内涵、实施路径及育人成效进行了思路分析与案例介绍,并对进一步持续改革工作进行了展望。

关键词：材料科学与工程本科专业人才培养教学改革

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