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为了对经受热疲劳的表面复合材料的设计提供理论依据,采用热震试验方法对通过真空实型铸渗(V-EPC)方法制备的WC/钢基表面复合材料的热疲劳性能进行了研究,重点讨论了表面复合材料热疲劳裂纹萌生及扩展的影响因素。结果表明,在本实验条件下Ni6025WC体积分数为15%时的热疲劳性能较5%时得到较大改善。表面复合材料的热疲劳裂纹的萌生和扩展的影响因素有以下几个方面:WC颗粒本身微观质量和热导率、复合层与基材中主要元素以及WC颗粒的平均热膨胀系数、复合层中WC颗粒之间的间距、由热震而产生的界面交变循环应力等。通过改善以上影响因素可以提高复合材料的热疲劳性能。
In order to provide a theoretical basis for the design of surface composites subjected to thermal fatigue, the thermal fatigue properties of WC / steel matrix composites prepared by vacuum solid infiltration (V-EPC) method were studied by means of thermal shock test. The influencing factors of thermal fatigue crack initiation and propagation on surface composites are discussed. The results show that under the experimental conditions, the thermal fatigue properties of Ni6025WC with volume fraction of 15% are better than 5%. The factors that affect the initiation and propagation of thermal fatigue cracks in the surface composites are as follows: the micro-mass and thermal conductivity of the WC particles themselves, the average coefficients of thermal expansion of the main elements in the composite layer and the matrix and the WC particles, the WC The spacing between particles, the interface produced by thermal shock alternating cyclic stress and so on. By improving the above factors can improve the thermal fatigue properties of composites.