碳含量对超细Ti(C,N)基金属陶瓷的结构及性能的影响

采用电子扫描显微镜、能量弥散X射线探测器、X射线衍射仪,研究了不同碳含量的Ti(C,N)基金属陶瓷的显微结构。同时测量了它们的维氏硬度以及横向断裂强度。实验结果表明:随着碳含量的增加,晶粒越细,降低了黏结相中钨、钼的溶解度,并使得重芯相(Ti,Mo,W)(C,N)的体积分数增加。如果添加的碳含量过少或者过多,都将使相组成偏离正常的两相区,生成第三相;碳添加量过少,则生成η相,过多则生成游离碳;而第三相的生成将显著降低金属陶瓷的机械性能。

Effect of Carbon Content on the Microstructure and Mechanical Properties of Superfine Ti(C,N)-Based Cermets

As some new tool materials which appeared in the seventies of last century, the Ti（C, N）-based cermets have been widely used in recent years because of their good properties. The microstructure of Ti（C, N）-based cermets with various carbon contents were studied by using scanning electron microscopy （SEM）, energy dispersive X-ray analysis （EDX） and X-ray diffractometry（XRD）. Vickers hardness and transverse rupture strength （TRS） were also measured. An increased carbon content resulted in the finer grain size, with decreased solution strength of tungsten and molybdenum in the binder phase, and a higher volume fraction of heavy （Ti, Mo, W）（C,N） cores. If the addition of carbon content was too little or too muchl the phase composition of material would deviate from the normal dual phase section and lead to the formation of the third phase： η -phase if the carbon content was too low or dissociative carbon if the carbon content is too high. and the formation of the third ohase would remarkably deteriorate the mechanical orooerties of cermets.