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Effects of gradient structure on the microstructures and properties of coated cemented carbides

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Journal of University of Science and Technology Beijing 2006年第4期13卷 363-367页

作者： Li Chen enxi wu Fei Yin Jia Li State Key Laboratory for Powder Metallurgy Central South University Changsha 410083 China Zhuzhou Cemented Carbide Cutting Tools Co. Ltd. Zhuzhou 412007 China

The effects of gradient structure on the microstructure and properties of coated cemented carbides were researched with optical microscopy （OM）, scanning electron microscopy （SEM）, strength measurements, and cutting tests. It shows that vacuum sintering of WC-Ti（C, N）-TaC-Co cemented carbides results in the formation of a surface ductile zone. The ductile zone prevents crack propagation and leads to the increase of transverse rupture strength of the substrate. The impact resistance of coated gradient inserts was obviously improved on the basis of maintaining resistance to abrasion and the forming mechanism of the gradient structure was also analyzed.

关键词： cemented carbide chemical vapor deposition (CVD) coating gradient structure

MICROSTRUCTURES AND MECHANICAL PROPERTIES OF Ti(C,N) FILMS DEPOSITED BY PEMSIP

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中国有色金属学会会刊：英文版 1999年第2期9卷 143-147页

作者： Li, Sheng Wang, Yukui wu, enxi Han, Huimin Central South Univ of Technology Changsha China

１ＩＮＴＲＯＤＵＣＴＩＯＮＰｌａｓｍａＥｎｈａｎｃｅｄＭａｇｎｅｔｒｏｎＳｐｕｔｅｒｉｎｇＩｏｎＰｌａｔｉｎｇ（ＰＥＭＳＩＰ）ｉｓａｎｅｗｋｉｎｄｏｆＰｈｙｓｉｃａｌＶａｐｏｒＤｅｐｏｓｉｔｉｏｎ（ＰＶＤ），ｗｈｉ... 详细信息

１ＩＮＴＲＯＤＵＣＴＩＯＮＰｌａｓｍａＥｎｈａｎｃｅｄＭａｇｎｅｔｒｏｎＳｐｕｔｅｒｉｎｇＩｏｎＰｌａｔｉｎｇ（ＰＥＭＳＩＰ）ｉｓａｎｅｗｋｉｎｄｏｆＰｈｙｓｉｃａｌＶａｐｏｒＤｅｐｏｓｉｔｉｏｎ（ＰＶＤ），ｗｈｉｃｈｂａｓｅｄｏｎｔｒａｄｉｔｉｏ...

关键词： PEMSIPinterlayeradhesion strengthcrystalline orientation relationship

THERMAL DEBINDING OF A NEW BINDER

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中国有色金属学会会刊:英文版 1997年第4期7卷 108-111页

作者： Zhou Jicheng Huang Baiyun wu enxi Yu Ligong Qu Xuanhui National Key Laboratory for Powder Metallurgy Central South University of TechnologyChangsha 410083 Changsha Railway University Changsha 410075

The thermal debinding of new binder in cemented carbide's extruding compacts and its debinding mechanism have been studied here. When the low molecular mass components (LMMC) in these new binder systems are changed, their thermogravimetric analysis (TGA) curves are very different. As the paraffin wax is the main LMMC, the new binder has been removed in two different temperature zones; while the temperature is at 240 ℃, the LMMC have been almost totally debinded. When a kind of short time polymer X is the main LMMC, there are no zones of low temperature debinding in the TGA curves. The differential thermal analysis curves show that a new single phase microstructural material composing with X and polymer A has been made in these cases.

关键词： cemented carbide extrusion pressing binder formulation thermal debnding

Sintering characteristics and microstructure of WC-Co-VC/Cr_3C_2 ultrafine cemented carbides

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Rare Metals 2009年第5期28卷 482-486页

作者： LEI Yiwen wu enxi School of Mechanical and Electronic Engineering Tianjin Polytechnic University Tianjin 300160 China State Key Laboratory of Powder Metallurgy Central South University Changsha 410083 China

The sintering characteristics, microstructure, and mechanical properties of ultrafine WC-12%Co-0.2%VC/0.5%Cr3C2 cemented carbides were investigated. Dilatometric and differential thermal analyses （DTA） indicate that the compacts start to shrink at 600°C, the shrinkage rate peak is at 1190°C, and the liquid formation temperature is lower than the W-C-Co eutectic temperature （1330°C）. Microstructure analysis results show that the cemented carbides with fine and homogeneous microstructure were obtained when sintered at 1430°C. Continuous and discontinuous grain growth was suppressed due to the synergistic action of VC/Cr3C2. The transverse rupture strength （TRS） of the samples reaches 4286 MPa, with the hardness HRA 92.1. The fine and homogeneous microstructure, alloy strengthening, and different phase constitutions of binder in the cemented carbides result in high hardness and TRS. Continuous and discontinuous grain growth was observed in the cemented carbide sintered at 1450°C, which results in significant decreases of hardness and TRS. It indicates that VC/Cr3C2 additions in the cemented carbides can only suppress the grain growth at a certain temperature.

关键词： cemented carbides sintering characteristic grain growth microstructure mechanical properties

GRINDING RESIDUAL STRESS OF CEMENTED CARBIDE

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中国有色金属学会会刊：英文版 1993年第1期3卷 49-52,57页

作者： Qian, Chongliang wu, enxi Lu, Haibo Central South University of Technology. Changsha 410083. China Chen, Ruikuan She, Zhenhui wu, Chunhua Zhenzhou Cemented Carbide Industry Company. Zhenzhou 412000. China

Grinding residual stress in the surface layer of WC-6 Wt—％Co hard alloy was measured by means of X-ray diffraction. The effects of various grinding parameters and treatment processes on the stress were studied. By means of electrolytic etching, the stress distribution along the depths beneath the surface was measured. The relationship between the stress and the service life of the alloy is discussed.

关键词： residual stress hard alloy X-ray diffraction

DEVELOPMENT OF MATERIAL USED FOR AVIATION APPARATUS AXLE JOURNALS

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中国有色金属学会会刊：英文版 1998年第2期8卷 19-24页

作者： wu enxi, Li Shen, Qian Chongliang and Zou ZhiqiangState Key Laboratory for Powder Metallurgy, Central South University of Technology, Changsha 410083, P. R. China

ＤＥＶＥＬＯＰＭＥＮＴＯＦＭＡＴＥＲＩＡＬＵＳＥＤＦＯＲＡＶＩＡＴＩＯＮＡＰＰＡＲＡＴＵＳＡＸＬＥＪＯＵＲＮＡＬＳ①ＷｕＥｎｘｉ，ＬｉＳｈｅｎ，ＱｉａｎＣｈｏｎｇｌｉａｎｇａｎｄＺｏｕＺｈｉｑｉａｎｇＳｔａｔｅＫｅｙ... 详细信息

ＤＥＶＥＬＯＰＭＥＮＴＯＦＭＡＴＥＲＩＡＬＵＳＥＤＦＯＲＡＶＩＡＴＩＯＮＡＰＰＡＲＡＴＵＳＡＸＬＥＪＯＵＲＮＡＬＳ①ＷｕＥｎｘｉ，ＬｉＳｈｅｎ，ＱｉａｎＣｈｏｎｇｌｉａｎｇａｎｄＺｏｕＺｈｉｑｉａｎｇＳｔａｔｅＫｅｙＬａｂｏｒａｔｏｒｙｆｏｒＰｏｗｄ...

关键词： Co25W alloy axle journals consumableelectrode melting wiredrawing agehardening

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硬质合金深冷处理

硬质合金 2007年第2期24卷 96-98页

作者：张平吴恩熙中南大学粉末冶金国家重点实验室

本文简要介绍了一种程控深冷处理装置的结构和性能,并介绍了几种不同牌号的硬质合金经深冷处理后性能的变化情况。

关键词：深冷处理结构性能硬质合金

(Ti,Al)N单层和TiN/(Ti,Al)N多层涂层的物理及力学性能研究

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粉末冶金技术 2006年第4期24卷 271-274页

作者：陈利吴恩熙尹飞汪秀全中南大学粉末冶金国家实验室

借助EPMA、XRD、SEM、纳米压痕、EDX、Rockwell A压痕、强度测试和切削实验研究了采用磁控溅射法在硬质合金基体上沉积的(Ti,Al)N单层和Ti N/(Ti,Al)N多层涂层的物理和力学性能。研究结果表明:两种涂层均与基体结合紧密,(Ti,Al)N为面心... 详细信息

借助EPMA、XRD、SEM、纳米压痕、EDX、Rockwell A压痕、强度测试和切削实验研究了采用磁控溅射法在硬质合金基体上沉积的(Ti,Al)N单层和Ti N/(Ti,Al)N多层涂层的物理和力学性能。研究结果表明:两种涂层均与基体结合紧密,(Ti,Al)N为面心立方结构;Ti N/(Ti,Al)N多层涂层具有更高的硬度、更低的脆性和更好的切削性能。

关键词：物理气相沉积 (Ti A1)N单层涂层 TiN/(Ti A1)N多层涂层

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超细Cr_3C_2粉末的制备

硬质合金 2006年第1期23卷 11-14页

作者：颜练武吴恩熙中南大学粉末冶金研究院国家重点实验室湖南长沙410083

将CrO3溶解于有机溶液中,通过喷雾干燥制得非晶态含铬的粉末前驱体,将前驱体粉末真空还原/碳化后得到超细Cr3C2粉末。采用X射线衍射仪﹑扫描电镜对工艺过程进行分析,分析结果表明:前驱体为10μm～20μm非晶态球形粉末,在真空中当温度升... 详细信息

将CrO3溶解于有机溶液中,通过喷雾干燥制得非晶态含铬的粉末前驱体,将前驱体粉末真空还原/碳化后得到超细Cr3C2粉末。采用X射线衍射仪﹑扫描电镜对工艺过程进行分析,分析结果表明:前驱体为10μm～20μm非晶态球形粉末,在真空中当温度升高到400℃时,前驱体粉末开始分解,生成微晶Cr2O3。当温度升高到550℃时,微晶Cr2O3迅速长大,前驱体粉末全部转变为Cr2O3与游离C原子级别混合均匀的复合粉末;温度升高到1150℃时得到碳化完全的Cr3C2粉末,粉末的一次颗粒粒度为0.5μm左右。

关键词：碳化铬喷雾干燥还原/碳化 X射线衍射仪扫描电镜