Mechanical behavior of a bulk nanostructured iron alloy
Mechanical behavior of a bulk nanostructured iron alloy
复制标题
DOI：
10.1007/s11661-998-0104-3
复制
发表时间：
1998-09-01
影响因子：
2.8
通讯作者：
Aifantis, EC
中科院分区：
文献类型：
--
作者：
Carsley, JE;Fisher, A;Aifantis, EC
用Fe-10 Cu制备了颗粒直径在45 nm和1.7 μ m之间的块状、完全致密的材料。通过在手套箱中球磨粉末，然后进行热等静压（热等静压）或粉末锻造来制备材料。通过对固结的粉末进行热处理获得较大的晶粒尺寸。散装材料相对干净，氧含量低于1500 wpm，其他污染物低于0.1 at.彼前这些材料的力学行为是独特的。在77至470 K的温度下，塑性变形的第一个也是唯一的机制是强烈的剪切带，这是伴随着一个完美的塑性应力-应变响应（应变硬化的情况下）。强度存在较大的拉压不对称性，在最大剪应力面和零伸长面上均未出现剪切带。这种行为，而不寻常的金属，已被观察到在无定形聚合物和金属玻璃。另一方面，细晶粒Fe-10 Cu材料在某些方面表现得像粗晶粒铁，特别是通过遵守Hall-Fetch方程，其常数合理地接近纯铁的常数，并且通过表现出与钢非常相似的低温机械行为。透射电子显微镜（TEM）的研究发现剪切带内的高度拉长的晶粒，表明剪切带发生的位错为基础的机制，至少在晶粒尺寸超过100纳米。讨论了细晶Fe-10 Cu与金属、聚合物、金属玻璃、辐射损伤金属和淬火损伤金属的异同。
Bulk, fully dense materials were prepared from Fe-10Cu with grain diameters between 45 nm and 1.7 mu m. The materials were prepared by ball milling of powders in a glove box, followed by hot isostatic pressing (hipping) or powder forging. Larger grain sizes were obtained by thermal treatment of the consolidated powders. The bulk materials were relatively clean, with oxygen levels below 1500 wpm and other contaminants less than 0.1 at. pet. The mechanical behavior of these materials was unique. At temperatures from 77 to 470 K, the first and only mechanism of plastic deformation was intense shear banding, which was accompanied by a perfectly plastic stress-strain response (absence of strain hardening). There was a large tension-compression asymmetry in the strength, and the shear bands did not occur on the plane of maximum shear stress or the plane of zero extension. This behavior, while unusual for metals, has been observed in amorphous polymers and metallic glasses. On the other hand, the fine-grained Fe-10Cu materials behaved like coarse-grained iron in some respects, particularly by obeying the Hall-Fetch equation with constants reasonably close to those of pure iron and by exhibiting low-temperature mechanical behavior which was very similar to that of steels. Transmission electron microscopy (TEM) studies found highly elongated grains within shear bands, indicating that shear banding occurred by a dislocation-based mechanism, at least at grain sizes above 100 nm. Similarities and differences between the fine-grained Fe-10Cu and metals, polymers, metallic glasses, radiation-damaged metals, and quench-damaged metals are discussed.