The current study presents a detailed investigation for the equal channel angular pressing of pure copper through two regimes. The first was equal channel angular pressing (ECAP) processing at room temperature and the second was ECAP processing at 200 °C for up to 4-passes of route Bc. The grain structure and texture was investigated using electron back scattering diffraction (EBSD) across the whole sample cross-section and also the hardness and the tensile properties. The microstructure obtained after 1-pass at room temperature revealed finer equiaxed grains of about 3.89 µm down to submicrons with a high density of twin compared to the starting material. Additionally, a notable increase in the low angle grain boundaries (LAGBs) density was observed. This microstructure was found to be homogenous through the sample cross section. Further straining up to 2-passes showed a significant reduction of the average grain size to 2.97 µm with observable heterogeneous distribution of grains size. On the other hand, increasing the strain up to 4-passes enhanced the homogeneity of grain size distribution. The texture after 4-passes resembled the simple shear texture with about 7 times random. Conducting the ECAP processing at 200 °C resulted in a severely deformed microstructure with the highest fraction of submicron grains and high density of substructures was also observed. ECAP processing through 4-passes at room temperature experienced a significant increase in both hardness and tensile strength up to 180% and 124%, respectively.

中文翻译：

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ECAP加工铜的实验和数值研究：显微组织演变，晶体织构和硬度均质性

当前的研究提出了通过两种方式对纯铜进行等通道角挤压的详细研究。第一个是在室温下进行等通道角冲压（ECAP）处理，第二个是在200°C下进行ECAP加工，最多可进行路径Bc的4遍加工。使用电子背散射衍射（EBSD）研究了整个样品横截面的晶粒结构和织构，以及硬度和拉伸性能。在室温下经过1遍后获得的微观结构显示，与起始材料相比，低至约3.89 µm的细等轴晶粒细化到亚微米级，具有高孪晶密度。另外，观察到低角度晶界（LAGB）密度的显着增加。发现该微观结构在样品横截面上是均匀的。进一步的应变直至2道次，结果表明平均晶粒尺寸显着减小至2.97 µm，并且晶粒尺寸可观察到不均匀分布。另一方面，将应变增加到4道次可以增强晶粒尺寸分布的均匀性。4次通过后的纹理类似于简单的剪切纹理，随机分布约7倍。在200°C下进行ECAP处理会导致微观结构严重变形，其中亚微米颗粒的比例最高，并且还观察到了高密度的亚结构。室温下通过4次ECAP处理的硬度和抗拉强度分别显着提高，分别达到180％和124％。另一方面，将应变增加到4道次可以增强晶粒尺寸分布的均匀性。4次通过后的纹理类似于简单的剪切纹理，随机分布约7倍。在200°C下进行ECAP处理会导致微观结构严重变形，其中亚微米颗粒的比例最高，并且还观察到了高密度的亚结构。室温下通过4次ECAP处理的硬度和抗拉强度分别显着提高，分别达到180％和124％。另一方面，将应变增加到4道次可以增强晶粒尺寸分布的均匀性。4次通过后的纹理类似于简单的剪切纹理，随机分布约7倍。在200°C下进行ECAP处理会导致微观结构严重变形，其中亚微米颗粒的比例最高，并且还观察到了高密度的亚结构。室温下通过4次ECAP处理的硬度和抗拉强度分别显着提高，分别达到180％和124％。在200°C下进行ECAP处理会导致微观结构严重变形，其中亚微米颗粒的比例最高，并且还观察到了高密度的亚结构。室温下通过4次ECAP处理的硬度和抗拉强度分别显着提高，分别达到180％和124％。在200°C下进行ECAP处理会导致微观结构严重变形，其中亚微米颗粒的比例最高，并且还观察到了高密度的亚结构。室温下通过4次ECAP处理的硬度和抗拉强度分别显着提高，分别达到180％和124％。