Chill zone copper with the strength of stainless steel and tailorable color
Chill zone copper with the strength of stainless steel and tailorable color
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DOI：
10.1016/j.actamat.2007.12.052
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发表时间：
2008-05
期刊：
影响因子：
9.4
通讯作者：
A. Yavari;K. Ota;K. Georgarakis;A. LeMoulec;F. Charlot;G. Vaughan;A. L. Greer;A. Inoue
中科院分区：
文献类型：
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作者：
A. Yavari;K. Ota;K. Georgarakis;A. LeMoulec;F. Charlot;G. Vaughan;A. L. Greer;A. Inoue
我们在这里报告90 at.%由于在铜模接触表面附近形成了厚的耐刮擦纳米晶冷却区，2- 4 mm厚的铜铸件的断裂强度高达1.9MPa。研究发现，当熔体过冷时，可形成厚度在200-300μm范围内的异常硬的纳米晶表面层：当合金成分使得铜模与液态合金的接触表面不作为晶体成核的优选位置时，熔体在激冷区过冷是可能的。这些铸件是迄今为止在宏观标本中报道的最硬的铜。它们的机械强度上级于许多不锈钢以及Cu-Be合金的机械强度，并且具有类似尺寸的Cu基块体金属玻璃（BMG）的机械强度的量级。此外，与铜基BMG不同的是，颜色和光泽可以通过元素添加来定制，以从类似铜到类似金。
We report here on 90at.% copper 2–4mm thick castings with fracture strengths up to 1.9MPa due to the formation of a thick, scratch-resistant nanocrystalline chill-zone next to the copper mold contact surfaces. It is found that the unusually hard nanocrystalline surface layers of thicknesses in the range of 200–300μm form when the melt can be undercooled: when the alloy composition is such that the contact surface of the copper mold with the liquid alloy does not serve as a preferred site for crystal nucleation, supercooling of the melt in the chill-zone is possible. These castings are the hardest coppers ever reported to date in macroscopic specimens. They have mechanical strength superior to those of many stainless steels as well as to Cu–Be alloys and of the order of those of Cu-based bulk metallic glasses (BMGs) of similar dimensions. In addition, and unlike in copper-based BMGs, the color and luster can be tailored by elemental additions to vary from copper-like to gold-like.