| 铌硅化物基超高温合金整体定向凝固组织和固/液界面形态演化 |
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| 引用本文： | 何永胜,郭喜平,郭海生,孙志平.铌硅化物基超高温合金整体定向凝固组织和固/液界面形态演化[J].金属学报,2009,45(9). |
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| 作者姓名： | 何永胜 郭喜平 郭海生 孙志平 |
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| 作者单位： | 西北工业大学凝固技术国家重点实验室,西安,710072 |
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| 基金项目： | 国家自然科学基金项目50671081;;凝固技术国家重点实验室自主研究课题项目07-TP-2008资助~~ |
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| 摘 要： | 采用有坩埚整体定向凝固技术研究了铌硅化物基超高温合金在不同过热温度下的定向凝固组织和固/液界面形态演化.研究结果表明:在抽拉速率均为15μm/s的条件下,当过热温度为1950℃时,定向凝固组织由初生铌基固溶体(Nb_(ss))枝晶和耦合生长的花瓣状(Nb_(ss)+γ-(Nb,X)_5si_3)共晶组成;当过热温度为2000和2050℃时,凝固组织为耦合良好的花瓣状共晶;但随着过热温度进一步提高到2100和2150℃,凝固组织演变为粗大树枝状Nb_(ss)和细小共晶.随着过热温度的提高,固/液界面形态出现树枝状界面→胞状界面→树枝状界面的形貌变化.
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| 关 键 词： | 铌硅化物 超高温合金 熔体过热温度 定向凝固组织 固/液界面形貌 |
MICROSTRUCTURE AND SOLID/LIQUID INTERFACE MORPHOLOGY EVOLUTION OF INTEGRALLY DIRECTIONALLY SOLIDIFIED Nb-SILICIDE-BASED ULTRAHIGH TEMPERATURE ALLOY |
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| HE Yongsheng,GUO Xiping,GUO Haisheng,SUN Zhiping.MICROSTRUCTURE AND SOLID/LIQUID INTERFACE MORPHOLOGY EVOLUTION OF INTEGRALLY DIRECTIONALLY SOLIDIFIED Nb-SILICIDE-BASED ULTRAHIGH TEMPERATURE ALLOY[J].Acta Metallurgica Sinica,2009,45(9). |
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| Authors: | HE Yongsheng GUO Xiping GUO Haisheng SUN Zhiping |
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| Abstract: | Nb-silicide-based ultrahigh temperature alloys have attracted considerable attentions as potential high temperature structural materials because of their high melting point,suitable density,good elevated temperature creep strength and acceptable room temperature fracture toughness. However,the shortcoming in both high temperature strength and high temperature oxidation resistance retarded their practical applications.Directional solidification and alloying can be used in overcoming these deficiencies at cer... |
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| Keywords: | Nb-silicide ultrahigh temperature alloy melt superheat temperature directionally solidified microstructure solid/liquid interface morphology |
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