钢与TiC颗粒之间界面润湿性分析

 TiC粒子具有高硬度、高熔点和高热力学稳定等特点,以TiC粒子作为增强相具有提高钢基体强度、耐高温和耐磨损等性能的潜力,近年来相关钢种的开发受到越来越多的关注。增强相颗粒与钢基体之间良好的润湿性是提高界面结合强度、防止颗粒在磨损过程中脱落的关键。因此,为了明确TiC粒子与钢基体之间的润湿程度,指导以TiC为增强相的耐磨钢的开发,采用高温座滴法观察钢液滴在TiC基片上的铺展行为,采用电子探针分析钢与TiC颗粒之间微区的元素分布,并结合热力学计算,探究高温下钢液与TiC之间界面润湿行为。结果表明,钢液与TiC之间的润湿性很好,在升温以及保温过程,钢样熔化后能通过TiC基片中的微孔快速渗入到基体内部,表现为钢样向下“坍塌”,直至钢样从观察窗口中完全消失。钢液进入TiC基片内部的同时,钢中氮元素向周围TiC相扩散。电镜分析表明钢液与TiC颗粒界面上没有产生新的相。TiC(TiN)与铁组成的二元相图表明,与TiN相比,TiC在钢液中有较大的溶解度,这解释了TiC-钢系统比TiN-钢系统润湿性好的原因。钢液与TiC颗粒之间的界面润湿性好且不发生化学反应,保证了TiC颗粒可作为增强相来提高钢的耐磨性能。为TiC颗粒与高钛钢之间的润湿性研究提供借鉴,为高钛耐磨钢成分的设计提供理论指导。

Analysis on interface wettability between TiC and steel

TiC particle has characteristics of high hardness, high melting point, high thermodynamic stability and so on. As the reinforcing phase, TiC has the potential to improve the strength, high temperature resistance and wear resistance of steel matrix. In recent years, much attention has been paid to the development of related steel grades. Good wettability between reinforcing phase and steel matrix is the key to improve interfacial bonding strength and prevent particles from falling off during the steel wear service. To clarify the wettability between steel and TiC and guide the development of wear-resistant steel with TiC as the reinforcing phase, the spreading behavior of steel droplets on TiC substrate was observed by sessile drop method, the element distribution of micro-area between steel and TiC was analyzed by electron probe microanalysis, and the wetting behavior at high temperature was explored with the aid of thermodynamic calculation. Results shows that the wettability between steel and TiC is pretty good, as the molten steel can quickly penetrate into the TiC substrate through the micropores during heating and insulation process. The steel sample collapses and disappears from the observation window. During the penetration, N element can diffuse to the surrounding. No new phase is generated at the interface between molten steel and TiC particles. The predicted binary phase diagram indicates that TiC has a higher solubility in liquid steel than that of TiN, confirming the better wettability of TiC-steel system than that of TiN-steel system. The interface wettability between molten steel and TiC particles is good and there is no chemical reaction at the interface, which ensures that TiC particles can be used as reinforcing phase to improve the wear resistance of steel. The result can provide a guidance for the wettability study between TiC particles and high-titanium steel, and the composition design of high-titanium wear-resistant steel.