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Long J.,State Key Laboratory of Cemented Carbide | Zhang Z.,Zhuzhou Cemented Carbide Group Corporation Ltd. | Xu T.,Zhuzhou Cemented Carbide Group Corporation Ltd. | Lu B.,Zhuzhou Cemented Carbide Group Corporation Ltd.
International Journal of Refractory Metals and Hard Materials | Year: 2013

In this paper, the effect of the carbon contents on the microstructure, mechanical properties and fracture behavior of WC-40 vol.% Ni3Al composites prepared by conventional powder metallurgy was studied. Microstructure examinations of WC-40 vol.% Ni3Al specimens indicated that the WC grain is round and fine compared with faceted and large WC grain of WC-Co composites. With increasing carbon contents, the WC morphology of WC-40 vol.% Ni3Al composites is similar and the size of WC grain is approximate and the distribution of binder phase becomes relatively uniform. Furthermore, composition analysis of binder phase showed that, with the increase of carbon content, the solubility of W in Ni3Al reduced slightly. The ~ 9 wt.% solubility of W in Ni3Al is much lower compared with ~ 22.4 wt.% of WC-40 vol.% Co composites. The hardness and transverse rupture strength of WC-40 vol.% Ni3Al composites decrease with increasing carbon contents slightly. WC-40 vol.% Ni3Al composites present higher hardness and lower transverse rupture strength than that of WC-40 vol.% Co composites. With increasing carbon contents, the fracture behavior of the WC-40 vol.% Ni3Al composites is affected greatly and the fracture mode changes from transgranular fracture towards intergranular fracture. © 2013 Elsevier Ltd. Source

Gu L.,Central South University | Huang J.,Central South University | Huang J.,Key Laboratory of Nonferrous Materials Science and Engineering | Tang Y.,Central South University | And 2 more authors.
Journal of Alloys and Compounds | Year: 2015

Effects of different post treatments on microstructure and properties of WC-11 wt.% Co cemented carbides were investigated in this paper. The different post treatments that are carried out to the cemented carbides are (a) heating and quenching in oil bath, (b) controlled cryogenic treatment. Various mechanical and microstructural characterization of these alloys including density, coercive force, hardness, transverse rupture strength, phase composition, W solubility of the cobalt phase, martensitic phase transformation of the cobalt phase and WC grain shape were analyzed before and after post treatments. The experimental results show that post treatments have a significant influence on WC-Co cemented carbides and the details of the experimental study are presented in this paper. © 2014 Elsevier B.V. All rights reserved. Source

Peng W.,State Key Laboratory of Cemented Carbide | Peng W.,Zhuzhou Cemented Carbide Group Corporation Ltd. | Kong D.,State Key Laboratory of Cemented Carbide | Kong D.,Zhuzhou Cemented Carbide Group Corporation Ltd.
Jingangshi yu Moliao Moju Gongcheng/Diamond and Abrasives Engineering | Year: 2016

The basic principle of synthesizing of gem-grade diamond using pressless "split sphere" high-pressure apparatus (BARS) was introduced. The property of cemented carbide anvils placed in BARS was presented, as well as the industrializing process of Chinese cemented carbide for BARS. Research showed that using WC-Co ultrafine composite powder after stirring ball milling, cold isostatic pressing and low pressure sintering would increase the uniformity of organizational structure, together with compressive strength and elastic modulus of hard alloy. The optimum project to machine self-localization anvil was to mutually act as reference and control product concentricity. Using M22/36 finishing wheel with a reasonable amount of feed in the grinding was the key to ensure the machining accuracy. © 2016, Zhengzhou Institute of Abrasives Grinding. All right reserved. Source

Zhang W.,Central South University | Peng Y.,Central South University | Du Y.,Central South University | Chen L.,Central South University | And 4 more authors.
International Journal of Refractory Metals and Hard Materials | Year: 2015

The C-Ti-V system was assessed by means of the CALPHAD (CALculation of PHAse Diagram) method. All of the experimental phase diagram data available from the literature were critically reviewed and assessed using thermodynamic models for the Gibbs energies of individual phases. The solution phases including the liquid, fcc, hcp and bcc were described by a substitutional solution model. There was no ternary compound in this system. A set of self-consistent thermodynamic parameters for the C-Ti-V system was obtained. Comparisons between the calculated and measured phase diagrams show that the experimental information is satisfactorily accounted for by the present thermodynamic description. The liquidus projection, three-dimensional isometric view and reaction scheme were generated by using the present thermodynamic parameters. © 2014 Elsevier Ltd. All rights reserved. Source

Zhang Z.-J.,State Key Laboratory of Cemented Carbide | Zhao S.-Z.,State Key Laboratory of Cemented Carbide | Peng W.,State Key Laboratory of Cemented Carbide | Zhang Q.-X.,Hunan University | Chen D.,Hunan University
Zhongguo Youse Jinshu Xuebao/Chinese Journal of Nonferrous Metals | Year: 2014

Cemented carbides are often served in extreme environments, under which they need to suffer mutual influence of cyclic stress, temperature (such as high temperature and cyclic temperature) and corrosive environment. Various fatigue fracture mechanisms, such as mechanical fatigue, thermal fatigue and corrosion fatigue, are the main reasons for the failure of the alloys. In terms of the fatigue crack initiation and propagation, the fatigue performance in cemented carbide was systematically discussed. The analysis shows that the fatigue crack is prone to initiate at coarse WC grains, pores, inclusions or binder phase pools, while the propagation performance of fatigue crack is influenced by various factors, including external factors of stress ratio, frequency, temperature and environment, and internal factors of microstructure and chemical composition. ©, 2014, Central South University of Technology. All right reserved. Source

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