(1. 湖南科技大学 高温耐磨材料及制备技术湖南省国防技术重点实验室,湘潭 411201;
2. 南昌航空大学 航空制造工程学院,南昌 330063;
3. 中南大学 材料科学与工程学院,长沙 410083)
摘 要: Al-Cu-Mg合金广泛应用于陀螺仪导航系统,其在长期热暴露环境下的尺寸稳定性是影响导航精度的关键。本文以第二相和残余应力演变为基础,利用X射线和球差透射电镜等微观结构分析手段,研究了长期热暴露作用对Al-Cu-Mg合金微尺寸变化的影响。结果表明:随着热暴露时间的增加,残余应力逐渐降低,Al2CuMg相则逐渐析出并长大,这使得合金的相对尺寸变化首先显著降低,之后轻微增加。合金的相对尺寸首先下降主要与残余应力释放有关,而之后上升则源于Al2CuMg相形貌的改变。与铝合金基体相比,Al2CuMg相会导致约5%的横向体积膨胀。
关键字: Al-Cu-Mg合金;第二相;微尺寸变化;残余应力
(1. Key Lab of High Temperature Wear Resistant Materials Preparation Technology of Hunan Province, Hunan University of Science and Technology, Xiangtan 411201, China;
2. School of Aeronautical Manufacturing Engineering, Nanchang Hangkong University, Nanchang 330063, China;
3. School of Materials Science and Engineering, Central South University, Changsha 410083, China)
Abstract:Al-Cu-Mg alloy is widely utilized as the key component of gyroscope navigation system, and its dimensional stability under the service environment is the determinant for navigation reliability. Based on the evolution of the second phases and residual stress, the corresponding mechanisms of long-time thermal exposure on the dimensional change of Al-Cu-Mg alloy were identified by XRD and HRTEM. The results show that with the increase of exposure time, the residual stress is released and Al2CuMg phases are gradually precipitated and coarsened. Meanwhile, the relative dimensional change firstly shows significant decrease and then slight increase. The dimensional change of this alloy is mainly associated with the release of residual stress at first and then related to the shape variation of Al2CuMg phase, which leads to about 5% transverse expansion in comparison with the Al matrix.
Key words: Al-Cu-Mg alloy; second phase; dimensional change; residual stress