Guangxi Key Laboratory of Superhard Materials

Guilin, China

Guangxi Key Laboratory of Superhard Materials

Guilin, China
SEARCH FILTERS
Time filter
Source Type

Xie D.,Hunan University | Wan L.,Hunan University | Song D.,Hunan University | Qin H.,Guangxi Key Laboratory of Superhard Materials | And 11 more authors.
Journal Wuhan University of Technology, Materials Science Edition | Year: 2016

We studied the effects of sintering temperature on FeCuCo based pre-alloyed powder for diamond bits. The FeCuCo composite was fabricated by co-precipitation method. With the addition of tungsten carbide (WC), sintering under different temperatures was investigated. Mechanical properties of the FeCuCo based matrix were systematically studied. The structure of the composite was evaluated by X-ray diffraction (XRD) and scanning electron microscope (SEM) was used to analyze the surface of the powder and matrix. The suitable sintering temperature was determined through differential scanning calorimeter (DSC). Micro drilling experiments were performed, and 820 °C was identified to be the ideal sintering temperature, at which the matrix shows the best mechanical properties and drilling performance. © 2016, Wuhan University of Technology and Springer-Verlag Berlin Heidelberg.


Xie D.-L.,Hunan University | Wan L.,Hunan University | Ning C.-X.,China Nonferrous Metal Guilin Geology and Mining Co. | Ning C.-X.,Chinese National Engineering Research Center for Special Mineral Materials | And 13 more authors.
Rengong Jingti Xuebao/Journal of Synthetic Crystals | Year: 2015

Fe based prealloyed powders were manufactured by co-precipitation method. The mechanical properties of samples sintered at different temperatures were tested. Alloy's structure formed during co-precipitation process was studied by XRD and the morphology was observed by SEM. The results show that the sintering temperature should be less than 900℃ and the mechanical properties of the alloys are the best when sintered at 850℃. The samples sintered at 850℃ have the uniform grain size and best mechanical retention of matrix applied to diamond. ©, 2015, Chinese Ceramic Society. All right reserved.


Xie D.-L.,Hunan University | Wan L.,Hunan University | Liu Z.-H.,Guangxi Key Laboratory of Superhard Materials | Liu Z.-H.,Chinese National Engineering Research Center for Special Mineral Materials | And 13 more authors.
Fenmo Yejin Cailiao Kexue yu Gongcheng/Materials Science and Engineering of Powder Metallurgy | Year: 2015

Fe-Cu based pre-alloyed powder containing Co, Ni and Sn elements was manufactured by co-precipitation method. Metal bond used for diamond tools were fabricated by vacuum hot press sintering Fe-Cu based pre-alloyed powder with adding mass fraction of 25% WC as skeleton phase under the temperatures of 700 to 860℃. Phase composition and morphology of pre-alloyed powder and metal bond were characterized by XRD and SEM. Mechanical properties including hardness, bend strength and abrasion ratio of the sintered matrix were also studied. The results show that solid solution has formed in the pre-alloyed powder owning solid solution phase with fine particle size of about 3 μm, smooth surface and irregular shape was obtained. DSC curve show that the atom diffusion and phase transformation undergo in 820~846℃. The matrix has little pore defect and optimal physical and mechanical properties when sintered at 820℃. The hardness is 113.9 HRB, relative density is 98.86% and bend strength is 1306.4 MPa. Meanwhile the bond force for diamond of the metal bond sintered at 820℃ reaches the maximum value. ©, 2015, Central South University. All right reserved.


Xie D.,Hunan University | Wan L.,Hunan University | Song D.,Hunan University | Wang S.,China Nonferrous Metal Guilin Geology and Mining Co | And 11 more authors.
Materials and Design | Year: 2015

The kinetic characteristics of Fe-Co-Cu pre-alloyed powders in the pressureless sintering process have been investigated. The expansion ratio, linear shrinkage, densification rate and effect of heating rate on the sintering have been analyzed. Based on the classical Arrhenius curve, the sintering activation energy has been calculated. Results show that the samples have a smaller expansion ratio before contracting when the Fe content is higher, and the final linear shrinkage ratio is larger too. The sintering carries out more efficiently and the final linear shrinkage ratio is larger when the samples at a lower heating rate. In the initial and final stage of sintering, the Arrhenius curve is suitable for the Fe-Co-Cu pre-alloyed powders and diffusion is the main transport mechanism. At the initial stage of sintering the sintering activation energy of Fe25%-Co15%-Cu60% powder is 453.11. kJ/mol, Fe45%-Co15%-Cu40% powder is 638.28. kJ/mol and Fe65%-Co15%-Cu20% powder is 504.6. kJ/mol, respectively. At the final stage of sintering the sintering activation energy of Fe25%-Co15%-Cu60% powder is 31.17. kJ/mol, Fe45%-Co15%-Cu40% powder is 20.09. kJ/mol and Fe65%-Co15%-Cu20% powder is 35.13. kJ/mol, respectively. The sintering activation energy in the middle stage is dominated by not only one diffusion mechanism so it is not suitable for the Arrhenius curve. © 2015 Elsevier Ltd.


Liu Z.-H.,Guangxi Key Laboratory of Superhard Materials | Liu Z.-H.,Chinese National Engineering Research Center for Special Mineral Materials | Liu Z.-H.,China Nonferrous Metal Guilin Geology and Mining Co. | Luo W.-L.,China Nonferrous Metal Guilin Geology and Mining Co. | And 6 more authors.
Jingangshi yu Moliao Moju Gongcheng/Diamond and Abrasives Engineering | Year: 2013

The single diamond grit loading experiments on photovoltaic materials namely monocrystalline silicon, polycrystalline silicon and sapphire are done by micro-hardness method. Loading characteristics with single diamond grit to these materials under different force are studied, and the relationship between the force and the loading deepness is analyzed. According to the test results, the diamond's force state and these materials' carving models are analyzed when these materials are cut by diamond tool.


Wang L.,Central South University | Wang L.,Guilin University of Electronic Technology | Rao G.H.,Guilin University of Electronic Technology | Zhang X.,Guilin University of Electronic Technology | And 3 more authors.
Ceramics International | Year: 2016

Reversals of magnetization and exchange bias field were observed in polycrystalline perovskite TmCrO3. Interestingly, the sign reversal of exchange bias can be driven by both temperature and cooling field. The temperature dependence of exchange bias reversal takes place around 31 K and the sign reversal of exchange bias driven by cooling field occurs when the system exhibits positive exchange bias. The reversals can be elucidated based on the antiferromagnetic coupling between the canted Cr3+ moments and Tm3+ moments. This antiferromagnetic coupling will hinder or benefit the reversal of Cr3+ moments or Tm3+ moments when the system were cooled under different magnetic field. © 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.


Wang L.,Central South University | Wang L.,Guilin University of Electronic Technology | Wang S.W.,Guilin University of Electronic Technology | Zhang X.,Guilin University of Electronic Technology | And 3 more authors.
Journal of Alloys and Compounds | Year: 2016

Reversals of magnetization and exchange bias field were observed around 19 K in polycrystalline perovskite chromite YbCrO3. Both the reversals can be elucidated based on the antiferromagnetic interaction between the ferromagnetic component of Cr3+ moments and the Yb3+ moments. The low field magnetization exhibits a perfect linear correlation with the magnetization shift resulted from the exchange bias effect. Distinguished from other exchange bias systems, the dependence of HE at 10 K on the cooling field shows an almost undamped feature up to 85 kOe, indicating the stable exchange bias states in respective temperature region. © 2015 Elsevier B.V. All rights reserved.


Zhang L.,Guangxi Key Laboratory of Superhard Materials | Zhang L.,National Engineering Research Center for Special Mineral Materials of China | Lin F.,Guangxi Key Laboratory of Superhard Materials | Lin F.,National Engineering Research Center for Special Mineral Materials of China | And 11 more authors.
International Journal of Refractory Metals and Hard Materials | Year: 2015

Cubic boron nitride (cBN) composites, using Al and HfC as the additives, were sintered under static high pressure of 5.0 GPa and at temperatures of 700 °C-1500 °C for 80 s. By analyzing the phase components of the sintered samples through the X-ray diffraction (XRD) analysis, we found that when the temperature increased from 700 °C to 900 °C, cBN reacted with Al and HfC, and produced AlN, AlB2, HfB2 and B2C5N2. Above 1000 °C, AlB2 was not stable. It decomposed and finally generated AlB12. At the meantime, the content of AlN, AlB12, HfB2 and B2C5N2 increased with Al disappearing. The Vickers hardness of the sintered samples increased with increasing the cBN content. The SEM and the abrasion ratio tests revealed that the well-sintered samples with homogeneous microstructure and the best wear resistance could be obtained at 5.0 GPa, 1300 °C for 80 s with the cBN content of 80 wt.%. © 2015 Elsevier Ltd.

Loading Guangxi Key Laboratory of Superhard Materials collaborators
Loading Guangxi Key Laboratory of Superhard Materials collaborators