摘要
与普通金属和合金材料相比,Ni-Al金属间化合物合金具有密度更低、强度和硬度更高、耐腐蚀等优点,在航空航天、汽车和能源领域具有广泛应用。然而,与合金性能密切相关的液态结构与金属间化合物之间的结构“遗传性”的理解仍然不够清晰。在此,本文采用同步辐射原位X射线成像和高能X射线衍射技术,观测Ni_(19.47)Al_(80.53)金属间化合物合金的凝固过程,采用微元法获得溶质分布及液态结构演化的可视化信息。结果表明:Ni_(19.47)Al_(80.53)合金的凝固过程存在溶质定向移动,金属间化合物微观组织的生长与液体中的团簇结构演化密切相关。类二十面体型团簇在富Al液相中偏聚,主导α(Al)相的生长;而类晶体型团簇在Al_(3)Ni金属间化合物附近偏聚,主导Al_(3)Ni相的生长。此工作拓展了对金属间化合物微观组织演化过程原子机理的理解,为控制和预测凝固组织提供理论指导。
Ni-Al intermetallic alloys have advantages of lower density,higher strength and hardness and more corrosion resistance compared with conventional metals and alloys,and have a wide range of applications in aerospace,automotive and energy fields.However,the structural"heritability"between liquid structures and intermetallic compounds is still not clearly understood,which is closely related to the alloy properties.Here,in situ observation of the solidification process for Ni19.47Al_(80.53) intermetallic compound alloy was investigated using synchrotron radiation X-ray imaging and high-energy X-ray diffraction techniques.Visualization of solute distribution and liquid structure evolution is obtained by the micro-element method.The results show that there is solute-directed movement during solidification.The growth of intermetallic compound microstructure is closely related to the evolution of clusters in the liquids.The enrichment of icosahedral-like clusters in the Al-rich liquid phase has a dominant effect on the growth of theα(Al)phase.While the enrichment of crystal-like clusters near the Al_(3)Ni intermetallic compound phase has a dominant effect on the growth of the Al_(3)Ni phase.The findings in this work extend the understanding of the atomic mechanism for the microstructure evolution of intermetallic compounds and provide theoretical guidance for controlling and predicting the solidification structure.
作者
赵艺萌
曾龙
夏明许
于鹏飞
李建国
ZHAO Yi-meng;ZENG Long;XIA Ming-xu;YU Peng-fei;LI Jian-guo(School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2023年第8期2549-2562,共14页
The Chinese Journal of Nonferrous Metals
基金
国家自然科学基金资助项目(52073174)
国家重点研发计划资助项目(2017YFA0403802)。
关键词
同步辐射
金属间化合物
微观组织
溶质再分配
结构演化
synchrotron radiation
intermetallic compounds
microstructure
solute redistribution
structural evolution
