Abstract

The heat treatable aluminium alloy AA2219 is subjected to mechanical stress relieving by way of cold deformation after solution treatment to relieve the quenched in stresses as thermal stress relieving is not possible due to the requirement of higher temperature than the ageing temperature. Cold deformation prior to aging has also been found to yield improved strength. Though this phenomenon is to some extent being exploited in aluminium alloy AA2219 sheets and plates, there is no experimental data available to understand the influence of cold compression on the extent of benefits obtainable on mechanical properties in forgings. In the present study to identify a thermo-mechanical treatment that can yield the maximum tensile strength, solution treated AA2219 forgings were subjected to cold deformation ranging from 0 to 25% and then artificially aged. The results indicates that the maximum room temperature tensile strength (both UTS and 0.2% PS) can be obtained at 10% post solution treatment cold deformation. As this alloy is being used for low temperature applications, it is very essential to assess the effect of higher cold compression on the low temperature (77 K) properties and the results show that the 77 K tensile properties more or less same beyond 2% cold deformation. As the weld properties are around 50% of the parent metal properties, any increase in the mechanical properties, is considered to be very crucial and very much needed for this alloy in the absence of aluminium–lithium alloy technology. Hence this study indicate that there is a good scope to increase the amount of cold compression after Solution treatment instead of restricting the same to 2%–5% maximum.

Graphic Abstract

中文翻译：

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热机械处理对AA2219铝合金手锻件组织和力学性能的影响

摘要

可热处理铝合金AA2219在固溶处理后通过冷变形的方式进行机械应力消除，以消除淬火应力，因为需要高于时效温度，因此无法消除热应力。还发现时效前的冷变形可提高强度。虽然这种现象在一定程度上在铝合金 AA2219 板材和板材中得到了利用，但没有可用的实验数据来了解冷压缩对锻件机械性能的影响程度。在本研究中，为了确定一种可以产生最大拉伸强度的热机械处理，固溶处理的 AA2219 锻件经过 0% 到 25% 的冷变形，然后进行人工时效。结果表明，在 10% 的后固溶处理冷变形下可以获得最大的室温拉伸强度（UTS 和 0.2% PS）。由于该合金用于低温应用，因此评估更高的冷压缩对低温 (77 K) 性能的影响非常重要，结果表明 77 K 拉伸性能在超过 2% 冷的情况下大致相同形变。由于焊接性能大约是母材性能的 50%，因此在没有铝锂合金技术的情况下，机械性能的任何提高都被认为是非常关键的，也是这种合金非常需要的。

图形摘要