Novel Ti-base nanostructure-dendrite composite with enhanced plasticity
Novel Ti-base nanostructure-dendrite composite with enhanced plasticity
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DOI：
10.1038/nmat792
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发表时间：
2003-01-01
期刊：
影响因子：
41.2
通讯作者：
Schultz, L
中科院分区：
文献类型：
--
作者：
He, G;Eckert, J;Schultz, L
单相纳米晶材料在室温下承受不均匀的塑性变形，导致非常有限的塑性应变（小于0-3%）。因此，这些材料显示出低的延展性，导致灾难性的失效，这严重限制了它们的应用。在这里，我们提出了一种新的原位形成的纳米结构的基体/韧性树枝状相复合显微组织的钛基合金，它具有高达14.5%的压缩塑性应变在室温下。在合理选择成分的基础上，通过控制凝固条件，合成了新型复合材料的微观结构。形变部分通过枝晶中的位错运动发生，部分通过纳米结构基体中的剪切带机制发生。枝晶作为限制过度变形的障碍物，通过将高度局部化的剪切带隔离在小的、离散的枝晶间区域中，并且有助于塑性。因此，我们建议可以使用微米级的韧性结晶相来增韧纳米结构材料。
Single-phase nanocrystalline materials undergo inhomogeneous plastic deformation under loading at room temperature, which results in a very limited plastic strain (smaller than 0-3%). The materials therefore display low ductility, leading to catastrophic failure, which severely restricts their application. Here, we present a new in situ-formed nanostructured matrix/ductile dendritic phase composite microstructure for Ti-base alloys, which exhibits up to 14.5% compressive plastic strain at room temperature. The new composite microstructure was synthesized on the basis of the appropriate choice of composition, and by using well-controlled solidification conditions. Deformation occurs partially through dislocation movement in dendrites, and partially through a shear-banding mechanism in the nanostructured matrix. The dendrites act as obstacles restricting the excessive deformation by isolating the highly localized shear bands in small, discrete interdendritic regions, and contribute to the plasticity. We suggest that microscale ductile crystalline phases might therefore be used to toughen nanostructured materials.