电子束熔炼Nb-Si系多元合金的组织和性能

Microstructure and Properties of Nb-Ti-Si-Cr-Al-Hf Alloy Prepared by Electron Beam Melting

采用电子束熔炼对Nb-Ti-Si-Cr-Al-Hf多元合金进行重熔,研究合金锭成分与组织的均匀性以及合金的硬度、室温断裂韧性、高温抗压性能。结果表明:电子束熔炼易导致合金元素的挥发损失,使得合金锭的成分不均匀;高的冷却速度有助于细小、均匀的等轴组织形成,其中硅化物相的显微硬度HV约为1100,是Nb固溶体相的3倍左右;电子束熔炼Nb-Si系多元合金的室温断裂韧性(KQ)约为10.3MPa.m1/2;在1250℃的抗压强度约为426.3MPa,且具有一定的高温塑性。

The Nb-Ti-Si-Cr-A1-Hf system alloy was prepared by electron beam melting method. The microstructure, hardness, room temperature fracture toughness and high temperature compressive behavior of the alloy were investigated. The results showed that the composition inhomogeneity at dif- ferent region of the ingot was serious, which may attribute to the vapor pressure of the elements, and the higher cooling rate was benefit to the formation of small and uniform microstructures. The micro- hardness （HV） of Nb silicide was about 1100, which was three times of that of Nb solid solution. In addition, the room temperature fracture toughness （KQ） of the alloy was about 10.3MPa · m^1/2. The compressive strength at 1250℃ of the Nb-Si in-situ composition was about 426.3MPa, and the alloy had good plastic deformation ability at high temperature.