Investigation of a directionally solidified NiAl/Cr(Mo) composite alloyed with Hf
Investigation of a directionally solidified NiAl/Cr(Mo) composite alloyed with Hf
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DOI：
10.1007/s11661-003-0025-0
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发表时间：
2003-11
期刊：
影响因子：
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通讯作者：
C. Cui;Y. Qi;J. Guo;H. Ye
中科院分区：
文献类型：
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作者：
C. Cui;Y. Qi;J. Guo;H. Ye
采用Bridgman定向凝固技术，在Al 2 O3-SiO2铸型中，在Ar气氛下对Hf合金化的NiAl/Cr（Mo）复合材料进行定向凝固。复合材料由NiAl基体、片状Cr（Mo）和连续分布的Ni 2AlHf组成。G相（Ni 16 Hf 6Si 7）在Si的存在下形成，Si是由陶瓷模具产生的污染物。界面是原子级平坦的，没有过渡层。经热等静压（hipping）和时效处理后，G相完全消失，胞间Ni 2AlHf相部分减少。复合材料的压缩屈服应力和拉伸强度高于许多NiAl基合金。由于热等静压和老化，在高温下存在脆化。讨论了G相和Heusler相对复合材料力学性能的影响。
A NiAl/Cr(Mo) composite alloyed with Hf was directionally solidified under a Ar atmosphere in Al2O3-SiO2mold by the standard Bridgman technique. The as-grown composite was composed of NiAl matrix, lamellar Cr(Mo), and semicontinuously distributed Ni2AlHf. The G phase (Ni16Hf6Si7) formed in the presence of Si, which was a contamination resulting from the ceramic mold. The interfaces were atomically flat with no transition layer. After hot isostatic pressing (hipping) and aging treatment, the G phase completely disappeared and the amount of intercellular Ni2AlHf phase was partially reduced. The compressive yield stress and tensile strength of the composite were higher than those of many NiAl-based alloys. Embrittlement existed at high temperatures, induced by hipping and aging. The effect of the G phase and Heusler phase on the mechanical property of the composite was also discussed.