The formation and evolution mechanism of amorphous layer surrounding Nb nano-grains in Nb-Al system during mechanical alloying process
The formation and evolution mechanism of amorphous layer surrounding Nb nano-grains in Nb-Al system during mechanical alloying process
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Nb-Al系机械合金化过程中Nb纳米晶周围非晶层的形成及演化机制
DOI：
10.1016/j.jallcom.2018.11.135
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发表时间：
2019-03
影响因子：
6.2
通讯作者：
Liu Y
中科院分区：
文献类型：
--
作者：
Li X;Wen X;Zhao H;Ma Z;Yu L;Li C;Liu C;Guo Q;Liu Y
系统地研究了Nb-Al系在MA过程中的显微组织和相演变。HRTEM观察和热处理实验中的晶化行为证实了短时球磨后Nb纳米晶周围存在Nb-Al非晶层。短时间球磨后，只有极少量的Al进入Nb晶格并替代Nb，而大部分Al主要集中在Nb纳米晶周围的非晶层中。通过界面热力学分析和计算，研究了Nb-Al二元系非晶层在MA过程中的相形成和演化规律。因此，Nb纳米晶周围非晶层{NbAl}的形成肯定存在正驱动力(≡-ΔG)。因此，这些非晶层可以在短时间球磨Nb-Al系统中稳定地形成和存在。随着球磨时间的延长，这种非晶层变得不稳定，当其厚度增加到临界厚度以上时，可以晶化为Nb(Al)固溶体。通过界面热力学计算预测了该非晶层的临界厚度，其计算值(约1.9 nm)与高分辨电子显微镜的观测厚度(约2.2 nm)在误差范围内是一致的。更重要的是，由于非晶层{NbAl}的晶化，Al在Nb晶格中的溶解度显著增加。我们的工作为更好地理解各种纳米体系在MA过程中复杂的微观结构和相演变提供了一个新的、合理的视角。
The microstructure and phase evolution in Nb-Al system during MA are systemically studied. The existence of Nb-Al amorphous layer surrounding Nb nano-grains after short-time ball milling was confirmed by the HRTEM observation as well as the crystallization behavior in the annealing experiment. It was also found that after short time milling, only very little Al can enter the crystal lattice of Nb and substitute for Nb, whereas most of Al mainly concentrate in this amorphous layer surrounding Nb nano-grains. What's more, interface thermodynamic analysis and calculation were employed to investigate the phase formation and evolution of this amorphous layer in Nb-Al binary system during MA process. Accordingly, positive driving force (≡-ΔG) definitely exists for the formation of the amorphous layer {NbAl} surrounding Nb nano-grains. Thus, these amorphous layers can form and exist stably in the short-time milled Nb-Al system. With the milling time prolonging, this amorphous layer becomes unstable and can crystallize into Nb(Al)sssolid solution when its thickness increases beyond a critical thickness. The critical thickness of this amorphous layer is also predicted by the interface thermodynamics calculation and the corresponding calculated value (approximately 1.9 nm) is consistent with the observed thickness (about 2.2 nm) by the HRTEM within the error range. More importantly, the solubility of Al in the lattice of Nb can be significantly increased resulting from the crystallization of this amorphous layer {NbAl}. Our work provides a new and rational perspective to well understand the complicated microstructure and phase evolution in various nano-sized systems during MA process.
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DOI：
10.1103/physrevb.54.9109
发表时间：
1996-10
期刊：
Physical review. B, Condensed matter
影响因子：
--
作者：
Benedictus;Böttger;Mittemeijer
通讯作者：
Benedictus;Böttger;Mittemeijer
影响因子：
--
作者：
B. Liu;W. Lai;Z. J. Zhang
通讯作者：
B. Liu;W. Lai;Z. J. Zhang
DOI：
10.1007/bf02876044
发表时间：
2000-02
期刊：
Science in China Series A: Mathematics
影响因子：
--
作者：
Y. Ouyang;X. Zhong;Weiming Wu
通讯作者：
Y. Ouyang;X. Zhong;Weiming Wu
影响因子：
9.4
作者：
S. Xi;Kesheng Zuo;Xiaogang Li;G. Ran;Jing-en Zhou
通讯作者：
S. Xi;Kesheng Zuo;Xiaogang Li;G. Ran;Jing-en Zhou
DOI：
--
发表时间：
1989-05
期刊：
--
影响因子：
--
作者：
F. D. Boer
通讯作者：
F. D. Boer