Hydrostatic cyclic extrusion–compression as a novel severe plastic deformation method in the processing of the rods is introduced and used for refining ultrafine-grained commercial pure aluminum. HCEC is solving the limitation of the conventional CEC in producing long-length samples by utilizing pressurized hydraulic fluid and eliminating the frictional effects. An increase in the length of the processable sample, a reduction in the processing loads, an intensification in the hydrostatic stress, and improvement in the strain distribution are the novel achievements of the HCEC. The capability of HCEC in grain refinement of the commercial pure aluminum was investigated by transmission electron microscopy analysis. The processed samples showed the grain sizes of 780 nm and 400 nm after the first and second passes of the HCEC, respectively. Furthermore, tensile and shear punch tests were utilized for investigation of the mechanical properties of the unprocessed and HCEC processed rods. An increase in the tensile and shear yield and ultimate strengths after the process confirmed the decreases in grain sizes. The tensile yield and ultimate strengths of the rod after the second cycle of the process reached 170 and 196 MPa, respectively. The same increasing trend as strength was shown in the microhardness after the HCEC. FEM analysis depicted the homogenous distribution of strain along the length of the sample. Also, the independency of the processing force to the length of the sample was shown by the FEM. The implementation of this novel technique looks very interesting for the industrial utilization of SPD techniques, especially in automotive and aerospace industries, which suffer from the limited size of the processing specimens.

中文翻译：

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静液压循环挤压压缩（HCEC）工艺；一个新的CEC对应物，用于加工长粒超细金属

介绍了静液压循环挤压-压缩作为棒材加工中一种新型的严重塑性变形方法，并将其用于精炼超细颗粒商业纯铝。HCEC通过利用加压液压油并消除摩擦效应，解决了传统CEC在生产长样品时的局限性。HCEC的新成就是增加了可处理样品的长度，减少了处理负荷，增加了静水压力以及改善了应变分布。通过透射电子显微镜分析研究了HCEC在商业纯铝晶粒细化中的能力。经过处理的样品在HCEC的第一次和第二次通过后分别显示出780 nm和400 nm的晶粒尺寸。此外，拉伸和剪切冲头测试用于研究未加工和HCEC加工棒的机械性能。加工后拉伸和剪切屈服强度以及极限强度的提高证实了晶粒尺寸的减小。在第二个过程循环后，棒材的拉伸屈服强度和极限强度分别达到170 MPa和196 MPa。HCEC后的显微硬度显示出与强度相同的增长趋势。有限元分析描述了沿样品长度的应变均匀分布。而且，有限元分析显示了加工力与样品长度的独立性。对于SPD技术的工业利用，尤其是在汽车和航空航天工业中，这种新颖技术的实施看起来非常有趣，