原位反应合成(TiB_2-Al_2O_3)/NiAl复合材料的微观组织

Microstructures of (TiB_2-Al_2O_3)/NiAl composite prepared by in-situ reaction synthesis

通过Ni、Al、TiO2和B203粉末之间的原位反应合成（TiB2-Al2O3）／NiAl复合材料，研究材料的物相组成和组织结构，并对典型组织的形成过程进行探讨。结果表明：反应产物由NiAl、TiB2和A1203这3种相组成。基体由NiAl和A1203组成，而TiB2颗粒规则，尺寸2～59m，呈簇状镶嵌在A1203中，少量弥散分布在NiAl基体上。分析认为TiB2的晶体结构、含量、所处NiAl熔体环境以及极快的冷却速度是影响其生长形态和分布的主要原因。

（TiB2-Al2O3）/NiAl composite materials were synthesized by in-situ reaction from Ni, A1, TiO2 and B2O3 mixed powders. The phase composition, microstructure and formation mechanism of typical microstructure were studied. The results show that the products contain NiAl, TiB2 and Al2O3 phases; the matrix is made of NiAl and Al2O3 phases; and the regular TiB2 particles are in size range of 2-5 μM, which are embedded by Al2O3 in clusters. A small amount of TiB2 particles disperse in the NiAL matrix. It is believed that the crystal structure, content, surroundings of molten NiAL and the fast cooling speed are the main reasons for determining the morphology and distribution of TiB2 particles.