Microstructure Evolution in Nb-12Si-22Ti-14Cr-2Al-2Hf Alloy Fabricated by Directional Solidification

作者：Su, Linfen; Jia, Lina; Yuan, Sainan; Zhang, Huarui; Zhang, Hu

来源：High Temperature Materials and Processes, 2014, 33(6): 495-498.

DOI：10.1515/htmp-2013-0090

• Nb-Si based alloy
• microstructure
• directional solidification
• crystal growth

In this work, the microstructure evolution of the Nb-12Si-22Ti-14Cr-2Al-2Hf alloy (at.%) fabricated by liquid-metal-cooled directional solidification (LMC) was investigated and the solidification behaviors were discussed. The results revealed that the growth rate was of crucial in controlling the microstructure of this alloy and the higher growth rate was beneficial to the formation of metastable phase Nb3Si. The microstructure of non-melted region consisted of Nb-SS dendrites, Nb-SS/Nb5Si3 eutectics and Ti-rich Nb-SS/Cr2Nb eutectics while the microstructure of quasi-steady-state growth region of this alloy consisted of Nb-SS dendrites, Nb3Si laths and Ti-rich Nb-SS/Cr2Nb eutectic. Nb3Si had the advantage of nucleation at medium/high growth rate. Therefore, the microstructure evolution occurred in this study was owing to the increase of growth rate.

• 出版日期2014-12
• 单位北京航空航天大学