Abstract

Various sets of heat treatments are applied on 7075 alloy in this study in order to reduce the treatment time and yet still achieve the similar mechanical property as the traditional T6 tempered alloy. The main parameters like solid solution treatment time, single aging temperature, as well as first aging duration in double aging treatment, first aging temperature and second aging temperature are studied and valued by hardness test. The double aging treatment at 125 °C for 60 min and then at 165 °C for 130 min is compared with traditional single aging treatment by using advanced Cs-corrected high-angle annular dark field scanning-transmission electron microscopy (HAADF-STEM). The precipitates and dispersoids found in those two corresponding samples are mainly Cr-containing large dispersoids, a few η particles and large quantity of fine precipitates like η′. The similarity of precipitates in them can well support the approximate hardness level of the double aged and single aged samples.

Graphic Abstract

中文翻译：

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7075合金单相和双相时效处理时效硬化和析出行为的比较

摘要

在本研究中，对7075合金进行了各种热处理，以减少处理时间，但仍获得与传统T6回火合金相似的机械性能。研究了固溶处理时间，单时效温度，双时效处理中的第一时效时间，第一时效温度和第二时效温度等主要参数，并通过硬度测试进行了评价。通过使用先进的Cs校正大角度环形暗场扫描透射电子显微镜（HAADF-STEM），将在125°C下进行60分钟然后在165°C下进行130分钟的双重时效处理与传统的单一时效处理进行比较。在这两个相应的样品中发现的沉淀物和弥散体主要是含铬的大弥散体，几个η粒子和大量细小沉淀物，如η'。它们中沉淀物的相似性可以很好地支持双时效和单时效样品的近似硬度水平。

图形摘要