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通过严重的塑料变形,在立方金属中接近纳米层结构的精细化极限
Yu Wei Liu1, Zhi Qiang Ren2, Kai Ning Wang1
1School of Materials Science and Engineering, Nanjing University of Science & Technology, Nanjing, 210014, China.
Scientific reports
|March 8, 2025
概括
由于竞争的精炼和回收工艺,纳米层 (NL) 金属的颗粒大小精炼停滞不前. 本研究探讨了NL结构中的这个极限,揭示了超越当前停滞点的进一步改进的潜力.
科学领域:
- 材料科学 材料科学 材料科学
- 金工业是一种金工业.
- 纳米技术 纳米技术
背景情况:
- 在金属中,颗粒大小的精炼通常会随着塑料应变的增加而停滞不前,这是由于脱位积累和热回收之间的平衡.
- 与等轴结构相比,纳米状 (NL) 结构中这种停滞点的行为仍然是一个悬而未决的问题.
研究的目的:
- 为了研究纳米状金属结构中颗粒大小精细化的停滞.
- 提出和建模一个物理精细化极限,以绕过热回收效应的叶片间距.
- 探索纳米状结构进一步改进的潜力.
主要方法:
- 在纯,和中制备纳米结构,使用等通道角处理 (ECAP) 后进行液滚动 (LNR).
- 基于几何精细化和三连接迁移引起的热粗化之间的平衡,模拟叶片间距停滞.
- 实验性表征叶片间距和拉伸强度.
主要成果:
- 成功制备了具有平均叶片间距为41nm (Ni),35nm (Ta) 和29nm (Nb) 的纳米叶片结构.
- 拉力强度达到了1.6 GPa (Ni),1.2 GPa (Ta) 和1 GPa (Nb).
- 实验结果表明,超出实现间距的进一步改进的潜力,因为它们超过了模拟的停滞点.
结论:
- 建立了叶片间距停滞的模型,考虑了通过三重结迁移的几何细化和热粗化.
- 在滚动过程中由剪切带驱动的三连接扩散被确定为限制纳米状结构精炼的关键因素.
- 在较高的液滚动减少下,研究金属中纳米状结构的进一步细化是可行的.
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