放电等离子烧结WC/Fe复合材料摩擦磨损性能

Tribology characteristics of WC/Fe composites by spark plasma sintering

  • 摘要: 采用放电等离子烧结技术制备了WC质量分数为40%的WC/Fe复合材料,研究了不同烧结温度条件下WC/Fe复合材料的致密度、组织、硬度及干摩擦磨损性能。利用SEM和XRD分析了不同烧结温度条件下存在的物相;采用销-盘摩擦磨损试验机(盘试样选用~80 μm的Al2O3砂纸,滑动距离约为950 m)测量了马氏体耐磨钢和WC/Fe复合材料在不同载荷下相对磨损率;用SEM观察磨损形貌,确定WC/Fe复合材料的磨损机制。结果表明:烧结温度为1080℃时,WC/Fe复合材料实现完全致密,WC陶瓷颗粒均匀分布在基体中并与基体界面结合良好;随着WC/Fe复合材料完全致密化,其硬度及耐磨性能逐渐提高; WC/Fe复合材料的耐磨性能远优于马氏体耐磨钢。WC/Fe复合材料磨损机制主要为氧化磨损和磨粒磨损。在低载荷条件下,颗粒脱离基体造成氧化膜破裂,促使材料表面受损;较高载荷条件下,WC陶瓷颗粒破碎加速氧化膜破裂,加快了材料的磨损。

     

    Abstract: The WC particles reinforced Fe matrix composites were fabricated by spark plasma sintering (SPS) with the WC particle mass friction of approximately 40%. The influence of sintering temperature on the density, micro-structure and mechanical properties of friction and wear properties of the WC/Fe composites were investigated. The phases of WC/Fe composites under different sintering temperatures were analyzed by XRD and SEM. The worn surface morphologeies of the two kinds of samples were observed by SEM and the wear mechanisms of samples were determined. The specific wear rates of the WC/Fe composites and matensitic wear-resistant steel were measured on a pin-disc tester (the counter face was a grade~80 μm Al2O3 abrasive paper). As the results, the complete densified WC/Fe composites can be obtained under 1080℃ and a homogenous distribution of WC particles within the Fe matrix with good interfacial bonding is obtained. The hardness and wear resistance of the WC/Fe composites increase gradually with the composites fully densification. The wear resistant performance of WC/Fe composites is far better than that of matensitic wear-resistant steel. The main wear mechanism of the matensitic wear-resistant steel is plough wear, and that of WC/Fe composites is oxidation wear and abrasive wear. Under low load condition, oxide film rupture is caused by particles break away from the substrate and lead to the worn surface; Under high load condition, brittle WC ceramics accelerate oxidation film broken, which lead to speed up the loss of WC/Fe composites.

     

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