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以高纯钽板为原料,采用原位反应法在HT300表面制备了碳化钽增强表面梯度复合材料。用扫描电子显微镜、X射线衍射仪、显微硬度计和磨粒磨损试验机对复合层的微观形貌、物相组成、显微硬度以及磨粒磨损性能进行了表征。结果表明:所得复合层的总厚度约为475μm。最表层为碳化钽致密陶瓷层,厚度约为170μm,其颗粒尺寸小于1μm,体积分数近似95%,显微硬度最高值达2328HV0.1;次表层为碳化钽颗粒分散层,其颗粒尺寸为0.5~1.5μm,体积分数从90%逐渐减小至基体,显微硬度由915HV0.1降低至410HV0.1;复合层与基体之间呈现良好的冶金结合。铁基表面碳化钽陶瓷增强梯度复合材料的耐磨性比灰口铸铁基体有大幅度提高;复合层的磨损是局部塑性变形、显微切削和增强颗粒的部分破碎等因素综合作用的结果。
Tantalum carbide reinforced surface gradient composites were prepared on the surface of HT300 by using high purity tantalum plate as raw material. The microstructure, phase composition, microhardness and abrasive wear properties of the composite were characterized by scanning electron microscopy, X-ray diffraction, microhardness tester and abrasive wear tester. The results show that the total thickness of the composite layer is about 475μm. The surface layer of tantalum carbide is a dense ceramic layer with a thickness of about 170 μm, a particle size of less than 1 μm, a volume fraction of about 95% and a maximum microhardness of 2328 HV0.1. The subsurface is a tantalum carbide particle dispersion layer having a particle size of 0.5 ~ 1.5μm, the volume fraction decreased from 90% to the matrix, the microhardness decreased from 915HV0.1 to 410HV0.1; the metallurgical bond between the composite layer and the matrix showed good. The wear resistance of iron-based tantalum ceramic reinforced graded composites is much higher than that of gray cast iron. The wear of composite layer is the result of the combined effect of local plastic deformation, micro-cutting and partial particle-breakage enhancement.