摘要:在本次设计中，采用了室温力学拉伸实验，布氏硬度测量，均匀化热处理等实验，对T79状态的7055铝合金厚板部分力学性能及完全退火组织转变进行了研究。实验中进行了3组7055铝合金室温力学拉伸实验，初步了解7055铝合金厚板在与轧制方向成0°，45°和90°方向上的抗拉强度与屈服强度，抗拉强度约为550Mpa,屈服强度约为520Mpa,板料表现出各向异性。为了改善组织性能，得到高塑性的7055铝合金组织，进行了6组单级均匀化制度的实验和4组多级均匀化制度的实验。根据微观组织的观察结果，确定了最合理的均匀化退火制度,470℃保温7h，经过1h稳定升温至480℃后保温3h，再经过1h稳定升温至490℃，在490℃保温1h。该退火制度下的晶粒均为等轴晶，晶粒的平均尺寸约为53μm，晶粒级别指数为7，并分析了7055铝合金在退火过程中晶粒的演变规律。实验结果表明，室温下T79态7055铝合金为高强铝合金，但其硬度会随着保温温度的升高与保温时间的延长而逐渐下降，而韧性及其延展性的性能会得到一定的提高。

关键词：7055铝合金；力学性能；均匀化；微观组织；布氏硬度

Abstract:In this study, the mechanical properties and complete annealing structure transition of 7055 aluminum alloy plate in T79 state were studied by means of room temperature tensile test, Brinell hardness measurement and homogenization heat treatment. In the experiment, three sets of 7055 aluminum alloy room temperature mechanical tensile test were used to understand the tensile strength and yield strength of 7055 aluminum alloy plate in 0 °,45 ° and 90 ° direction with the rolling direction. For 550Mpa, the yield strength is about 520Mpa, the sheet exhibits anisotropy. In order to improve the microstructure and properties of the 7055 aluminum alloy, the experiments of six groups of single-stage homogenization system and four groups of multi-stage homogenization system  were carried out. According to the observation results of microstructure, the most reasonable homogenization annealing system was determined. The temperature was maintained at 470  ℃ for 7h. After 1h, the temperature was increased to 480  ℃ for 3h. After 1h, the temperature was raised to 490 ℃. The grain size is about 53μm and the grain size  index is 7, and the evolution rule of 7055 aluminum alloy during the annealing process is analyzed. The experimental results show that the T79 state 7055 aluminum alloy is a high strength aluminum alloy at room temperature, but its hardness will decrease with the increase of the holding temperature and the holding time, and the toughness and ductility will be improved.

Key words: 7055 aluminum alloy; mechanical properties; homogenization; microstructure; Brinell hardness

目 录

第一章绪论 1

1.17055铝合金的成分 1

1.27055铝合金的性能特点 2

1.37055铝合金常见的热处理工艺 3

1.4本文主要的研究内容及意义 4

第二章7055铝合金的实验内容、方法及设备 6

2.1室温力学拉伸 6

2.2完全退火制度 7

2.3硬度测量 10

第三章拉伸实验、完全退火组织与硬度分析 13

3.17055铝合金厚板不同方向拉伸件分析 13

3.27055铝合金各均匀化制度下的组织观察和分析 14

3.2.1均匀化前7055铝合金组织分析