铸造凝固冷速对原位自生（TiW）C／Fe复合材料组织的影响

研究了不同的铸造凝固冷速对原位自生10vol%(TiW)C/Fe复合材料显微组织的影响。结果表明,在原位合成的10vol%(TiW)C/Fe复合材料中,(TiW)C相是唯一的第二相,均匀、弥散分布于基体中,其形态基本上呈块状,条状较少。在块状(TiW)C相中,Ti和W元素的分布是不均匀的,芯部富Ti,边缘富W。当冷速较快时,形成的第二相颗粒趋于等轴状,条状共晶组织消失,有利于基体耐磨性的提高;当冷速较慢时,第二相颗粒数量多,尺寸小,且随冷速的降低在该复合材料中形成了大量的共晶组织。适当提高冷却速度,有利于获得较理想的复合材料显微组织。

Effect of cooling rate in cast solidification on microstructures of in-situ(TiW)C/Fe composites

The effect of cooling rate in cast solidification on the microstructures of 10vol% (TiW)C/Fe composites was investigated. The results show that in the 10vol% (TiW)C/Fe composites, as the only second phase, (TiW)C has two kinds of morphologies, homogeneously distributed in iron matrix, and most of them are spherulic with few rod-like. Within the spherulic (TiW)C phase, there is an inhomogeneous distribution of titanium and tungsten. Its core is rich in titanium, while the periphery is rich in tungsten. When the cooling rate is fast, the amount of second phases is less than that in slow cooling rate, and the net eutectic is separated out along the interfaces, meanwhile, the rod-like is disappeared, which is favorable for the increasing of wear resistance. When the cooling rate is slow, the size of second phases becomes smaller, and a quantity of eutectic is found, which is harmful to mechanical properties. Thus, an moderate increase in cooling rate favors to attain ideal microstructures.