Abstract

In the present study, a novel rolling method is proposed, which is called Multi-Rotational Flat Rolling (MRFR). The novelty of this work is the application of this special method of flat rolling to severely deform metal. The rolling is performed so as to preserve the square shape of the transverse section of the sample. During the process, the transverse-sectional area of the workpiece is gradually reduced, while the sample length is simultaneously increased. The experiment was carried out on commercially pure aluminium. An annealed sample was subjected MRFR up to the attainment of a maximum fourfold reduction in the transverse-sectional area. A microstructure analysis showed that the process resulted in a material having a refined microstructure of less than 1 µm. Nevertheless, the majority of the grain boundaries (over 70 pct) were of the low-angle type. As a result of the grain refinement and the increase in dislocation density, a clear improvement in the strength of the deformed material was observed. The increase in yield stress was 157 pct, the increase in ultimate tensile strength was about 56 pct, while the decrease in the value of elongation to failure was 12.8 pct.

中文翻译：

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精轧组织细化和提高纯铝机械强度的新型轧制方法

摘要

在本研究中，提出了一种新颖的轧制方法，称为多比例平轧（MRFR）。这项工作的新颖之处在于采用这种特殊的平轧方法使金属严重变形。进行轧制以保持样品横截面的正方形。在此过程中，工件的横截面积逐渐减小，而样品长度同时增加。该实验是在商业纯铝上进行的。对退火过的样品进行MRFR，直至横截面面积最大减少四倍。微观结构分析表明，该过程导致材料的精细微观结构小于1  µ米 然而，大多数的晶界（超过70 pct）是低角度类型。作为晶粒细化和位错密度增加的结果，观察到变形材料的强度明显改善。屈服应力的增加是157 pct，极限抗拉强度的增加是大约56 pct，而断裂伸长率的降低是12.8 pct。