Structure and Tensile Strength of Pure Cu after High Pressure Torsion Extrusion
Structure and Tensile Strength of Pure Cu after High Pressure Torsion Extrusion
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DOI：
10.3390/met9101081
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发表时间：
2019-10
期刊：
影响因子：
2.9
通讯作者：
D. Nugmanov;A. Mazilkin;H. Hahn;Y. Ivanisenko
中科院分区：
文献类型：
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作者：
D. Nugmanov;A. Mazilkin;H. Hahn;Y. Ivanisenko
通过高压扭转挤压（HPTE）加工后，对商业纯（CP）铜棒状样品（直径11.8毫米，长度35毫米）的显微组织和力学性能进行了表征。在 HPTE 过程中，CP 铜承受极高的应变，范围从样品中心区域的 5.2 到其边缘的 22.4。整个样品部分的这种高但变化的应变导致 HPTE 铜呈现出梯度结构，由中心区域的细晶粒和中间半径区域和样品边缘的超细晶粒组成。对拉伸特性的详细分析表明，具有梯度结构的 HPTE 铜的强度与经过严重塑性变形 (SPD) 技术后的铜相似，通常呈现均匀结构。详细分析各种强化机制对HPTE铜整体强度的贡献如下：主要贡献来自Hall-Petch强化，因为梯度结构中存在高角度和小角度晶界，这对位错运动起到了有效的阻碍作用。因此，霍尔-佩奇方程中应考虑两种类型的边界。这项关于 CP 铜的研究证明了使用 HPTE 方法生产工业用散装高强度金属材料的潜力。
The microstructure and mechanical properties of rod-shaped samples (measuring 11.8 mm in diameter and 35 mm in length) of commercially pure (CP) copper were characterized after they were processed by high pressure torsion extrusion (HPTE). During HPTE, CP copper was subjected to extremely high strains, ranging from 5.2 at central area of the sample to 22.4 at its edge. This high but varying strain across the sample section resulted in HPTE copper displaying a gradient structure, consisting of fine grains in the central area and of ultrafine grains both in the middle-radius area and at the sample edge. A detailed analysis of the tensile characteristics showed that the strength of HPTE copper with its gradient structure is similar to that of copper after severe plastic deformation (SPD) techniques, typically displaying a homogeneous structure. Detailed analysis of the contributions of various strengthening mechanisms to the overall strength of HPTE coper revealed the following: The main contribution comes from Hall–Petch strengthening due to the presence of high and low angle grain boundaries in gradient structure, which act as effective obstacles to dislocation motion. Therefore, both types of boundaries should be taken into account in the Hall–Petch equation. This study on CP copper demonstrated the potential of using the HPTE method for producing high-strength metallic materials in bulk form for industrial use.