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Song J.,University of Franche Comte | Song J.,Xiamen Honglu Tungsten Molybdenum Industry Co. | Barriere T.,University of Franche Comte | Liu B.,Southwest Jiaotong University | And 2 more authors.
Powder Metallurgy | Year: 2010

The sintering behaviours of injection moulded components in 316L stainless steel powder are investigated by means of the bending and dilatometric tests in the furnace. Various thermal cycles are realised for different tests. The experimental results are used to determine the parameters of uniaxial viscosity and sintering stress in the viscoplastic constitutive law, which is important for description of the sintering behaviours. The sintering models are implemented into the finite element solver, incorporated with the identified parameters, to simulate the size change and shape distortion of powder injection moulded components during the sintering process. The sintering simulation takes into account the green inhomogeneity caused by powder binder segregation in the previous injection process. The simulation results for the sintering process of a three-dimensional wheel component are compared with the experimental ones. It proved validity of the sintering model and the approaches for parameter determination proposed in the study. © 2010 Maney Publishing. Source


Zhao S.X.,CAS Hefei Institutes of Physical Science | Liu F.L.,CAS Hefei Institutes of Physical Science | Qin S.G.,Advanced Technology and Materials Co. | Song J.P.,Xiamen Honglu Tungsten Molybdenum Industry Co. | Luo G.-N.,CAS Hefei Institutes of Physical Science
Fusion Science and Technology | Year: 2013

The first attempt at developing chopped W fiberreinforced W (WW) composites without an engineered interface or inter-phase employing hot isostatic pressing (HIP) has been made in order to study the feasibility of the powder metallurgy (PM) fabrication methodology. Microstructures and flexural properties of sintered compacts have been examined by an optical microscope (OM), a scanning electron microscope (SEM) equipped with an electron back scattering diffraction (EBSD) instrument and three-point bending (3PB) tests. There are some chrysanthemum-like grains around each fiber in W matrices. Mechanical properties, namely strength and pseudoplasticity, of the sintered compacts are far from satisfactory. Abnormal grain growth does not seem to have a preferen-tial growing direction according to EBSD results. Possible causes for the abnormal grain growth and further mechanical property optimizations are hereby presente. Source


Song J.,Xiamen Honglu Tungsten Molybdenum Industry Co. | Yu Y.,Xiamen Honglu Tungsten Molybdenum Industry Co. | Zhuang Z.,Xiamen Tungsten Co. | Lian Y.,Southwestern Institute of Physics | And 2 more authors.
Journal of Nuclear Materials | Year: 2013

W-Cu functionally graded materials (FGMs) are designed to be a transition layer between CuCrZr bulk material and a W surface layer in plasma-facing components. In this study, a type of in-house developed ultrafine W-Cu composite powder has been used to fabricate a W-Cu FGM, which consists of three layers of W-10Cu, W-32Cu, and W-60Cu respectively. The sintered FGM has a homogeneous microstructure and a residual porosity of less than 3.3%. The W-10Cu side of the FGM has been coated with pure W using an optimized chemical vapor deposition (CVD) process with an increased deposition rate of 0.8 mm/h. The thickness of the coating is around 2 mm and the density is as high as 19.23 g/cm3. The columnar grain size of CVD-W at the end of deposition is approximately 20-50 μm in the direction parallel to the substrate and 1-1.5 mm in the direction perpendicular to the substrate. Compared with plasma-sprayed W-Cu FGM and W coating, the FGM and CVD-W developed in this study have a better microstructure, which is important for the thermal and physical properties of the components. © 2013 Elsevier B.V. All rights reserved. Source


Lv Y.,Xiamen Honglu Tungsten Molybdenum Industry Co. | Song J.,Xiamen Honglu Tungsten Molybdenum Industry Co. | Lian Y.,Southwestern Institute of Physics | Yu Y.,Xiamen Honglu Tungsten Molybdenum Industry Co. | And 2 more authors.
Journal of Nuclear Materials | Year: 2015

The ultra-high purity (>99.9999 wt.%) and fully dense (19.23 g/cm3) tungsten (W) by chemical vapor deposition (CVD) was prepared with the deposition rate higher than 0.6 mm/h. The thermal diffusivity, specific heat, heat conductivity and coefficient of thermal expansion of CVD-W at the temperature range of 473-1273 K were measured. Thermal shock tests were carried out on a 60 kW electron-beam material testing scenario to investigate the crack-resistant performance of CVD-W, and the crack initiation threshold energies of CVD-W were achieved in 5 ms heating duration. Compared to forged-W, the higher heat conductivity (160.5-111 W/(m K)) and threshold energy of crack initiation (1.1-1.65 MJ/m2) of CVD-W can be attributed to the material characteristics including high purity, fully dense, rough surface composed of pyramid-like grains, and the columnar grain structures. © 2014 Elsevier B.V. All rights reserved. Source


Sun B.,Northeastern University China | Song J.,Xiamen Honglu Tungsten Molybdenum Industry Co. | Yu Y.,Xiamen Honglu Tungsten Molybdenum Industry Co. | Zhuang Z.,Xiamen Tungsten Co. | And 4 more authors.
International Journal of Refractory Metals and Hard Materials | Year: 2014

Tungsten-copper (W-Cu) composites containing 10 wt.% Cu (W-10Cu) were prepared by pressing and sintering a type of ultrafine composite powder. Constituent phases, grain size and orientation relationship between W and Cu grains were characterized and investigated. The results show that W-10Cu composites are composed of W and Cu elementary substance and orientation relationship between W and Cu grains is defined as 1̄1̄4Cu/ /01̄1W and (131)Cu//(200)W. The existence of the orientation relationship depends largely on the two factors. First, the grain sizes of both W and Cu were in the nanoscale range. Secondly, the interplanar spacing between both phases can match well owing to the residual stress of the W/Cu interface. Consequently, the obtained composites exhibited high density and excellent thermal conductivity. © 2014 Elsevier Ltd. Source

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