EFFECT OF Si ADDITION ON THE MICROSTRUCTURE AND ROOM TEMPERATURE TENSILE PROPERTIES OF HIGH Nb-TiAl ALLOY
EFFECT OF Si ADDITION ON THE MICROSTRUCTURE AND ROOM TEMPERATURE TENSILE PROPERTIES OF HIGH Nb-TiAl ALLOY
复制标题
Si添加对高Nb-TiAl合金显微组织和室温拉伸性能的影响
DOI：
10.11900/0412.1961.2015.00075
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发表时间：
2015-04
影响因子：
2.3
通讯作者：
Lin Junpin
中科院分区：
文献类型：
--
作者：
Wang Yanli;Ye Teng;Song Lin;Lin Junpin
高Nb-TiAl合金作为新一代TiAl合金，因其具有比传统TiAl合金更高的使用温度和更好的抗氧化性能而受到越来越多的关注。结果表明，高Nb TiAl合金中的硅化物粒子为Nb 5Si 3，而不是TiAl合金中的Ti 5Si 3。研究了Nb 5Si 3相对高Nb-TiAl合金显微组织和室温拉伸性能的影响。实验结果表明，硅化物的析出温度在1000~1200 ℃之间。菌落位于殖民地界、B（B2）分离区和g /a2片层之间。硅的加入提高了铸态合金的拉伸性能。由于Nb 5Si 3相的形成导致了B（B2）相稳定元素Nb含量的降低。因此，由于Si的添加，B（B2）相的体积分数明显降低。但热处理后，随着热处理温度的升高，含Si高Nb-TiAl合金的拉伸性能逐渐降低。硅化物颗粒沿沿着片层析出，导致裂纹的产生和扩展。此外，由于张应力，硅化物颗粒进一步沉淀，从而增加了裂纹扩展的速率。添加Si
High Nb-TiAl alloys, which being regarded as a new generation TiAl alloy, had attracted more and more attention for their higher operating temperature and better oxidation resistance than conventional TiAl alloys. It was found that silicide particles in high Nb-TiAl alloys were Nb 5 Si 3 rather than Ti 5 Si 3 precipitated in TiAl alloys. In this work, the effect of Nb 5 Si 3 phase on the microstructure and room-temperature tensile properties of high Nb-TiAl alloy was studied. The experimental results showed that the precipitation temperature of silicide was between 1000~1200 ℃ . Precipitates located in the colony boundary, b (B2) segregation and between g / a 2 lamella. The tensile properties of as-cast alloy with Si addition increased. Because the formation of Nb 5 Si 3 precipitates resulted in the reduction of Nb content, which was one of b (B2) phase stable elements. Therefore, the volume fraction of b (B2) phase obviously decreased due to Si addition. However, after heat treatments, the tensile properties of Si containing high Nb-TiAl alloy gradually reduced with the increasing of heat treatment temperature. Silicide particles which precipitated along lamella leaded to generation and propagation of cracks. Moreover, silicide particles further precipitated due to tensile stress which increased the rate of crack propagation. Si addition