摘要:
研究了一种Ti诱导反应熔体无压浸渗制备复合材料的方法: 通过凝胶注模成型工艺, 以蔗糖为造孔剂制备了多孔Ti-WC陶瓷骨架预制体, 真空状态下, 在1370℃以Fe-Cr-C合金熔体无压浸渗该预制体, 经过原位反应制备了(W,Ti)C/Fe复合材料。利用SEM-EDS、 XRD对复合材料的组织结构、 元素组成及相组成进行了测试和分析。采用旋转圆盘式摩擦试验机以SiC砂浆为磨料研究了(W,Ti)C/Fe复合材料的耐磨性。结果表明: 在浸渗过程中骨架中的Ti元素的溶解析出与C元素的原位反应促进了浸渗过程的进行, 在1370℃保温1 h, 金属液即渗透整个多孔骨架, 并且在浸渗过程中仍然维持着骨架的形状, 浸渗过程中Ti-C-WC原位反应生成具有芯-壳结构的中间富Ti、 边缘富W的(W,Ti)C增强相。摩擦磨损实验结果表明, (W,Ti)C/Fe复合材料具有优异的抗磨粒磨损性能, 其耐磨性优于工业用耐磨铸铁。
Abstract:
As a new kind of method to prepare composites, pressureless Ti-activated reactive melt infiltration was investigated. The Ti-WC porous ceramics skeleton preform was prepared by gelcasting using sugar as pore former. Under vacuum condition, the Ti-WC porous ceramics skeleton preform was infiltrated by Fe-Cr-C alloy melt with in-situ reaction to prepare the (W,Ti)C/Fe composites. The microstructures, element composition and phase analysis were investigated by using SEM-EDS and XRD. And the wear resistance was studied using a rotating disc rig with SiC mortar as the abrasive material. The results show that the infiltration process is accelerated by the dissolution and precipitation of titanium and the in-situ reaction between titanium and carbon. At 1370℃ for 1 h, the porous ceramics skeleton is permeated by the melt, and the space structure has not been changed in the infiltration process. The reinforced phase (W,Ti)C which has a concentration gradient of Ti and W from core to the periphery is produced by in-situ reaction of Ti-C-WC. As the result of the wear testing shown, (W,Ti)C/Fe composites have excellent abrasive wear resisitance, which is better than that of the wear resistant cast iron commonly used in industry.
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