Influence and comparison of contaminate partitioning on nanocrystalline stability in sputter-deposited and ball-milled Cu–Zr alloys
Influence and comparison of contaminate partitioning on nanocrystalline stability in sputter-deposited and ball-milled Cu–Zr alloys
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DOI：
10.1007/s10853-020-05135-y
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发表时间：
2020-09
影响因子：
4.5
通讯作者：
Xuyang Zhou;J. Schuler;Charlette M. Grigorian;D. Tweddle;T. Rupert;Lin Li;G. Thompson
中科院分区：
文献类型：
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作者：
Xuyang Zhou;J. Schuler;Charlette M. Grigorian;D. Tweddle;T. Rupert;Lin Li;G. Thompson
摘要明确纳米晶稳定性的机制是揭示特定合金如何延缓晶粒生长的关键。即使在同一种合金中，关于这种机制也经常存在重大争论。在这里，我们比较了两种处理方法-高能球磨和薄膜沉积-在制备和随后的两步退火（500°C/24小时，然后温度上升到900°C，然后样品保持1分钟并淬火）中制备纳米晶Cu-Zr。利用进动电子衍射（PED）和原子探针层析成像（APT）对晶粒稳定性和二次相含量进行了定量分析。研磨后的粉末样品显示，研磨后的Zr溶质大部分处于氧化物/碳化物状态，退火后无明显变化。相比之下，薄膜样品在沉积时几乎全部呈现单质Zr，但在真空退火后明显氧化。氧的显著吸收是由于薄膜的高表面积与体积比，以及在沉积状态下富含元素Zr的柱状颗粒。此外，在溅射沉积时，许多这些边界被玻璃化，在退火时丢失。粉末的PED未观察到这些玻璃状边界。讨论了溶质与污染物质发生反应的结果与纳米晶和微观结构稳定性的关系。基于APT测量的二次相颗粒的定量，给出了使用齐纳钉钉预测晶粒尺寸的方法，以更好地确定它们对纳米晶稳定性的贡献。图形抽象
AbstractAscertaining the mechanism(s) of nanocrystalline stability is a critical need in revealing how specific alloys retard grain growth. Often significant debate exists concerning such mechanisms, even in the same alloy. Here, we compare two processing methods—high-energy ball milling and thin film deposition—in the fabrication and subsequent two-step annealing (500 °C/24 h followed by a temperature ramp to 900 °C whereupon the sample was held for 1 min and quenched) for nanocrystalline Cu–Zr. Using precession electron diffraction (PED) and atom probe tomography (APT), the grain stability and secondary phase content was quantified. The milled powder sample revealed that the Zr solute was largely in an oxide/carbide state after milling with no significant change upon annealing. In contrast, the thin film sample showed nearly all elemental Zr upon deposition but significant oxidation after the vacuum anneal. The significant uptake of oxygen is contributed to the high surface area-to-volume ratio of the film coupled with columnar grains that were enriched in elemental Zr in the as-deposited state. Furthermore, upon sputter deposition, many of these boundaries were vitrified which was lost upon annealing. These glassy boundaries were not observed by PED of the powders. The consequence of when the solute reacts with contaminate species is discussed in relation to nanocrystalline and microstructural stability. The use of Zener pinning predicted grain sizes, based on the quantification of the secondary phase particulates measured by APT, are given to better ascertain their contribution to nanocrystalline stability.Graphic abstract