Nanotechnology enabled design of a structural material with extreme strength as well as thermal and electrical properties
Nanotechnology enabled design of a structural material with extreme strength as well as thermal and electrical properties
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DOI：
10.1016/j.mattod.2019.09.024
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发表时间：
2019-12
期刊：
影响因子：
24.2
通讯作者：
M. Rajagopalan;K. Darling;C. Kale;S. Turnage;Raj Kiran Koju;B. Hornbuckle;Y. Mishin;K. Solanki
中科院分区：
文献类型：
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作者：
M. Rajagopalan;K. Darling;C. Kale;S. Turnage;Raj Kiran Koju;B. Hornbuckle;Y. Mishin;K. Solanki
纳米晶（NC）合金用于各种结构应用的潜在益处源于其增强的机械强度。然而，NC材料中的变形诱导的晶粒生长降低了强度，并且是即使在低温下也会发生的广泛报道的现象。控制这样的行为是关键的块体纳米晶金属在各种先进的工程应用中的成熟。在这里，我们公开了当NC材料真正热机械稳定对抗晶粒生长时，晶界滑动和旋转被抑制的机制。与任何其它已知的纳米晶体金属不同，在极端温度下，在加载过程中不存在滑动和旋转与沿晶界的短路溶质扩散有关，所述短路溶质扩散沿着晶界引起溶质簇的形成并因此引起晶界结构的显著变化。这种不寻常的行为与既定规范的背离导致许多相互排斥的性能的强烈增强，例如热机械强度、抗蠕变性和异常高的电导率/热导率。这项工作表明，铜基纳米晶合金可用于传统的铜基多晶材料是不可行的应用。
The potential benefits of nanocrystalline (NC) alloys for use in various structural applications stem from their enhanced mechanical strengths. However, deformation-induced grain growth in NC materials reduces the strength and is a widely reported phenomenon occurring even at low-temperatures. Controlling such behavior is critical for the maturation of bulk nanocrystalline metals in various advanced engineering applications. Here, we disclose the mechanism by which grain boundary sliding and rotation are suppressed when a NC material is truly thermo-mechanically stabilized against grain growth. Unlike in any other known nanocrystalline metals, the absence of sliding and rotation during loading, at extreme temperatures, is related to short-circuit solute diffusion along the grain boundaries causing the formation of solute clusters and thus a significant change of the grain boundary structures. The departure of this unusual behavior from the well-established norm leads to a strong enhancement of many mutually exclusive properties, such as thermo-mechanical strength, creep resistance, and exceptionally high electrical/thermal conductivity. This work demonstrates that Cu-based nanocrystalline alloys can be used in applications where conventional Cu-based polycrystalline materials are not viable.