| This article studies transition-metal carbides nanocrystalline powders WC whichprepared by Mechanical Alloying, and use X-ray diffraction theory for different millingtime qualitative and quantitative analysis to study the phase composition, crystal particlesize, the phase component content, and the mechanical alloying process. On the otherhand, the powder after ball miling was sintered by the spark-plasma-sintering(SPS), Andthe phase composition, grain size analyzer of sintered body was analyzed by X-raydiffraction, and compared the changes before and after sintering samples. In addition, thischapter studies the displacement and displacement rate with the sintering temperatureshowed characteristic changes in the course of sintering, and theoretically analyze thespark-plasma-intering process. Finally, we conducted a series of performance tests on thesintered body.XRD analysis showed that, under the action of the high energy ball milling, thesamples had undergone the mechanical activation and the chemical activation, synthesisof new materials W2C and WC. With the increase in milling time, the content of Wwas gradually reduced, the W2C content first increased and then decreased, WC contentincreased gradually. For the sample milled70hours, the the content of WC had reaced100%. This shows that in the milling process of W2C is only the intermediate product ofWC. The particle size and grain size of original tungsten powders had refined, explainedthat the method of Mechanical alloying can refine grain.The results of analysis showed that with the extension of the milling time, the carboncontent of prepared bulk had increased, the density decreased and the hardness rose, so wefound that the ball milling time can be used to tune the ratio x of C/W. The hardnessmaximum is2250HV belonged to milling40hours body. It can be seen that withmechanical alloying and spark plasma sintering method we can produce ahigh-performance transition-metal carbide nanocrystals WC... |
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