Abstract

The mechanical properties and microstructure of AM60 Magnesium alloy processed by a new cyclic extrusion channel angular pressing (CECAP) technique were investigated in this research. In this novel method, a low extrusion ratio stage was added at the end of the CECAP process to enhance the hydrostatic stresses and equivalent strain. The structure was refined from the average grain size of ~ 76 µm for the annealed samples to 2.63 µm in the new CECAP after four passes. While for the CECAP and ECAP processes, it was 3.43 and 6.98 µm, respectively. Experimental results of the proposed CECAP process showed an improvement in the mechanical properties after the second pass that were stopped for the ECAP process. However, the hardness of the CECAP-processed and proposed samples was constantly increasing. This increase in hardness was 196% and 175% for the proposed CECAP and CECAP processes after four passes compared to the unprocessed sample, respectively. Moreover, the compressive yield stress and ultimate compressive strength of the CECAP-processed samples were higher in all passes; however, they were smaller than those of the proposed CECAP process. The hydrostatic compressive stresses and higher plastic strain in the proposed technique helped in further refining of the grains, which can effectively improve the mechanical properties.

Graphic Abstract

中文翻译：

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新型严重塑性变形技术处理的AM60镁合金的组织和力学性能

摘要

研究了一种新型的循环挤压通道角挤压（CECAP）技术加工的AM60镁合金的力学性能和组织。在这种新方法中，在CECAP工艺结束时增加了一个低挤出率阶段，以增强静液压应力和等效应变。经过四次通过后，结构从退火样品的平均晶粒尺寸〜76 µm精炼到新的CECAP中的2.63 µm。对于CECAP和ECAP工艺，分别为3.43和6.98 µm。拟议中的CECAP工艺的实验结果表明，第二次通过后，ECAP工艺停止了机械性能的改善。但是，CECAP处理和建议的样品的硬度一直在增加。与未经处理的样品相比，建议的CECAP和CECAP工艺经过四次通过后，硬度增加分别为196％和175％。而且，CECAP处理过的样品的抗压屈服应力和极限抗压强度在所有过程中都较高。但是，它们比拟议中的CECAP程序要小。所提出的技术中的静水压应力和较高的塑性应变有助于晶粒的进一步细化，从而可以有效地改善机械性能。

图形摘要