Abstract

The influence of working temperature and number of passes on the mechanical properties of aluminium alloy, AA 5083, processed by cyclic expansion and extrusion (CEE) is discussed. The specimens were processed up-to 10 CEE passes at 200 °C, 300 °C and 400 °C. The average grain size of the starting annealed material was 84.5 ± 6.8 μm, with 39.4% being of the high-angle grain boundaries (HAGBs) type. After 8 CEE passes at 200 °C the material had an average grain size of 3.3 ± 0.6 μm and 41.3% of the grain boundaries were of the high-angle type (HAGBs). The combined effect of an increase in dislocation density and reduction in grain size as a result of CEE processing contributed to an increase in hardness and strength of the alloy. At 200 °C, the specimen exhibited uniform hardness values with a maximum improvement of 104% after 8 passes and the ultimate tensile strength had also increased by 64% compared with the unprocessed condition. However, the mechanical properties decreased in the specimens that were processed at the higher temperatures of 300 °C and 400 °C.

Graphic abstract

中文翻译：

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温度和通过次数对循环膨胀挤压铝镁合金力学性能的影响

摘要

讨论了工作温度和通过次数对循环膨胀和挤压（CEE）加工的铝合金AA 5083力学性能的影响。在200°C，300°C和400°C的条件下，对样品进行了多达10次CEE处理。初始退火材料的平均晶粒尺寸为84.5±6.8μm，其中39.4％为高角度晶界（HAGBs）类型。在200°C下经过8次CEE后，材料的平均晶粒尺寸为3.3±0.6μm，并且41.3％的晶界为高角度类型（HAGB）。CEE加工导致位错密度增加和晶粒尺寸减小的综合效果有助于提高合金的硬度和强度。在200°C下，与未经处理的试样相比，试样在8次通过后表现出均匀的硬度值，最大改善了104％，极限抗拉强度也增加了64％。但是，在300°C和400°C的较高温度下处理的样品的机械性能下降。

图形摘要