Fabrication of Nano Grain Tungsten Compact by Mechanical Milling Process and Its High Temperature Properties
Fabrication of Nano Grain Tungsten Compact by Mechanical Milling Process and Its High Temperature Properties
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DOI：
10.4028/www.scientific.net/msf.503-504.573
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发表时间：
2006-01
期刊：
影响因子：
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通讯作者：
E. Oda;K. Ameyama;S. Yamaguchi
中科院分区：
文献类型：
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作者：
E. Oda;K. Ameyama;S. Yamaguchi
机械球磨(MM)是SPD工艺中的一种，主要应用于钨粉和钨粉的球磨。MM法制备的W和W-Re粉末即使熔化温度较高，也容易形成纳米晶结构。纳米晶的形成机制为：球磨多轴变形，在最高333K的温度下，首先形成盘饼状颗粒结构。极密集的位错导致了晶界的细化，最终形成了高角度晶界的纳米晶结构。得到了直径约为10 nm的纳米颗粒。采用放电等离子烧结工艺对MM粉末进行了烧结。研究了MM粉末的烧结和高温变形行为。MM处理使W粉末能够在1273K下烧结，而没有MM处理的W粉末不能在相同的温度下烧结。稀土的加入防止了烧结过程中的晶粒长大，从而提高了压坯的硬度。在高温下观察到了晶粒度约为450 nm的W-10quality%再烧结体的大变形。
Mechanical milling (MM), which is one of SPD process, is applied to W powder and W-Remixed powder. MM processed W and W-Re powders easily form nano grain structure even though they have high melting temperature. The nano grain formation mechanism in these powders is as follows: multi axial deformation of the powders by milling, at the temperature of 333K at most, produces pan-cake grain structure at first. Extremely dense dislocations result in grain sub-division, and finally nano grain structure with high angle boundary forms. Nano grains with approximately 10 nm in diameter are obtained. The MM powders are sintered using Spark Plasma Sintering process. Sintering and high temperature deformation behaviors of the MM powders are also investigated. The MM treatment enables W powder to be able to sinter at 1273 K while the powder without MM could never sintered at the same temperature. Re addition prevents grain growth during sintering and thus increases hardness of the compacts. A large deformation of W-10mass%Re sintered compact, whose grain size is approximately 450nm, is observed at elevated temperatures.