Microstructure and mechanical properties of Nb–Si alloys fabricated by spark plasma sintering
Microstructure and mechanical properties of Nb–Si alloys fabricated by spark plasma sintering
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DOI：
10.1016/j.pnsc.2013.01.009
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发表时间：
2013-02
期刊：
影响因子：
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通讯作者：
W. Liu;Yongming Fu;J. Sha
中科院分区：
文献类型：
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作者：
W. Liu;Yongming Fu;J. Sha
研究了放电等离子烧结（SPS）制备的Nb/Nb 5Si 3（Nb：Nb 5Si 3 = 90：10，80：20，70：30和50：50）双相Nb-Si二元合金的显微组织演变和力学性能。采用SPS技术制备了相对密度大于99.5%的致密Nb/Nb 5Si 3样品。SPS样品由Nb和Nb_5Si_3相组成，NbO氧化物含量小于3%。Hv和1150°C和1250°C下的压缩强度通过增加硬化Nb 5Si 3相的分数而整体提高。当Nb_5Si_3含量从10%增加到50%时，0.2%屈服强度σ_0.2在1150 ℃时从175 MPa增加到420 MPa，在1250 ℃时从110 MPa增加到280 MPa。有趣的是，断裂韧性，KQ，散装SPS样品似乎是不敏感的相分数。在Nb 5Si 3含量为10%~ 30%时，KQ值提高了约100%;在Nb 5Si 3含量为50%时，KQ值提高了约50%。
This paper deals with microstructural evolutions and mechanical properties of Nb–Si binaries containing dual-phase Nb/Nb5Si3with Nb to Nb5Si3fraction ratios of 90:10, 80:20, 70:30 and 50:50, prepared by spark plasma sintering (SPS). Dense Nb/Nb5Si3samples with a relative density larger than 99.5% were obtained by SPS processing. The SPS samples consist of the Nb and Nb5Si3phases with less than 3% fraction of NbO oxide. Hv at room temperature, and compressive strength at 1150°C and 1250°C of the bulk SPS alloys increase monolithically by enhancing fraction of the stiffening Nb5Si3phase. For example, 0.2% yield strength, σ0.2, increases from 175MPa to 420MPa at 1150°C and from 110MPa to 280MPa at 1250°C, when the Nb5Si3fraction increases from 10% to 50%. It is interesting that the fracture toughness, KQ, of the bulk SPS samples seems not to be sensitive to phase fraction. Heat treatment, however, plays a key role on the KQas compared with that of the as-sintered state, at the corresponding Nb5Si3fraction and considerably improves the KQby about 100% for samples with the Nb5Si3fractions of 10%–30%, and by about 50% for the sample with 50% Nb5Si3fraction.