Al-Ti-B 4 C体系熔体内燃烧合成TiC-TiB 2 颗粒局部增强钢基复合材料 *
摘要
From the point of view of the application, the service life of component usually relies on the wear resistance of local region, and it is desirable that the local region of component rather than the whole component is reinforced by ceramic particulate to offer high-wear resistance. In this study, the TiC-TiB2 particulates locally reinforced steel matrix composites were fabricated by an SHS-casing route using an Al-Ti-B4C system. The effects of the Al content on the microstructure and wear resistance of the composites were investigated. The results show that the TiC and TiB2 particulates were formed in all the preforms with various Al contents (0 similar to 50%, mass fraction) after the high temperature (about 1873 K) steel melt was poured into the mold and the molten steel, to the different extents, penetrates into the synthesized samples. The Al content in the preforms has a large effect on the constitute of the synthesized products and the quantity, size and distribution of the ceramic phases in both the reinforced region and the transition region. With the increase of the Al content, the quantity and average size of the ceramic particles as well as holes decrease, the type and quantity of the intermetallic compounds in the products increase and the gradient distribution of the ceramic particles in the transition region weakens and finally disappears. The wear resistance of the locally reinforced composites is much superior to that of the unreinforced steel matrix, and the best appears in the sample free of Al composition, and then followed by the samples of 30%Al, 10%Al and 50% Al in turn.