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Guo J.-L.,Henan University of Science and Technology | Wei S.-Z.,Henan Engineering Research Center for Wear of Material | Pan K.-M.,Henan Engineering Research Center for Wear of Material
Zhuzao/Foundry | Year: 2015

The cast-infiltrated layer with high manganese and high chromium cast iron can be achieved on the surface of ZG45 steel by cast-infiltration process, by changing the manganese content in cast infiltration alloyed powder, the effects of manganese on microstructure and properties of cast-infiltrated layer were studied. The results show that the thickness of casting layer are 6 mm or more without pores; when alloy powder with Mn 11%, the carbide with daisy-shaped uniformly distributed in the austenite matrix of cast structure, the carbides are mainly Cr7C3, Fe3C, Cr23C6, etc., and the dense cast-infiltrated layer without pores was obtained. The bond between cast-infiltrated layer and substrate is metallurgical bond; the maximum hardness is nearly HRC 56. ©, 2015, Chinese Mechanical Engineering Society. All right reserved. Source


Zhou H.,Henan University of Science and Technology | Wei S.-Z.,Henan Engineering Research Center for Wear of Material | Xu L.-J.,Henan Engineering Research Center for Wear of Material
Zhuzao/Foundry | Year: 2014

High tungsten High speed steel is prepared by casting. The organizational and carbides change in high speed steels after heat treatment is studied on by using XRD, OM, SEM. The M6C carbides is discovered in as-cast HSS mainly along the crystal boundary distribution, and between M6C carbide and substrate have the transition region. After annealing, the transition region disappears. A few tiny secondary carbides separate out along the crystal boundary after quenching. After quenching has the few tiny secondary carbides along the crystal boundary separation, and more secondary carbides separate out along crystal boundary after tempering. The as-cast high tungsten high speed steel is quenched and tempered treatment directly without annealing, the organizational mainly is directly the austenite, moreover only separates out the few secondary carbides. Source


Ren Y.,Henan University of Science and Technology | Zhang G.,Henan Engineering Research Center for Wear of Material | Wei S.,Henan University of Science and Technology | Li J.,Henan University of Science and Technology | Xu L.,Henan University of Science and Technology
Advanced Materials Research | Year: 2013

Using the steel containing 0.45 percent of carbon as matrix, high carbon ferrochrome as cast-penetrated agent, the steel-based surface composites were fabricated by conventional cast-penetrating process combined with the thermite reaction. The influence of thermite reaction on the microstructures and properties of cast-infiltration layer was researched. The results show that the interfacial bonding is metallurgical fusion between cast-infiltration layer and the matrix under the suitable technological parameters, the thermite reaction during the process of cast-penetrated realizes thermal compensation for liquid metal and improves the mobility of liquid steel by reducing oxidation film of liquid steel surface, consequently increase the thickness of cast-infiltration layer; The ceramic phase of Al2O3 which is generated during the thermite process improves the microhardness of cast-infiltration in a certain extent. © © (2013) Trans Tech Publications, Switzerland. Source


Zhai C.,Henan University of Science and Technology | Li Y.,Henan University of Science and Technology | Ma X.,Henan Engineering Research Center for Wear of Material | Wei S.,Henan Engineering Research Center for Wear of Material | Xu L.,Henan Engineering Research Center for Wear of Material
Advanced Materials Research | Year: 2011

Using montmorillonite (MMT) and sodium carboxymethylcellulose (CMC) as raw materials, CMC/MMT nanocomposites were prepared by the solution intercalation technique. The microstructures of MMT before and after being intercalated were characterized by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). The results of XRD showed that when the adding amount of CMC increased from naught to 70wt%, the structures of MMT have no change basically; when the adding amount of CMC increased to 80wt%, the decrease of MMT (001) was significant; when the adding amount of CMC reached to 90wt%, the diffraction peak of (001) disappeared, which indicated that the layers of MMT have been exfoliated along (001) and the CMC/MMT intercalated structure has been obtained. The observations by HRTEM showed that the shapes of MMT are layer aggregation or agglomerated particles. The MMT added with 90wt% CMC has changed into intercalated structure with alternating MMT and CMC order mainly, and the intercalated structure was characterized at the atomic scale. © (2011) Trans Tech Publications. Source


Li J.-W.,Henan University of Science and Technology | Zhang E.-Z.,HIGH-TECH | Wei S.-Z.,Henan Engineering Research Center for Wear of Material | Zhang G.-S.,Henan University of Science and Technology
Fenmo Yejin Cailiao Kexue yu Gongcheng/Materials Science and Engineering of Powder Metallurgy | Year: 2011

After mixed the secondary ammonium molybdate, lanthanum nitrate and citric acid solution, the nano molybdenum powder doped with rare earth (RE) element lanthanum has been prepared by means of liquid-liquid doped method and sol-gel method. The effects of the initial solution pH value and citric acid addition on the gel forming characterization were investigated. The desizing processes of the xerogel were discussed. And the existing forms of the RE element in the doping molybdenum powder were analyzed. The results show that, the optimum process to prepare the xerogel with loosen, porous and net-like structure is that the pH value for the precursor solution is 1, and the mass ration of the citric acid to the lanthanum nitrate is 1.5, the optimum desizing process is the direct sintering method at 560°C. After two-step hydrogen reduction, the spherical and homogeneous doped molybdenum powder can be obtained. The existing form for the lanthanum element in the doped MoO3 powder is La2O3 or La-Mo composite oxides which adhere to the surface of the MoO3 particles. However, for the doped molybdenum powder, the La-Mo composite oxides are decomposed in the reduction process, the existing form is La2O3. The particle size of the doped RE-Mo powder and the La2O3 particles are about 500 nm and 100 nm, respectively. Source

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