(1. 中南大学 材料科学与工程学院，长沙 410083；
2. 中南大学 有色金属材料科学与工程教育部重点实验室，长沙 410083)
摘 要: 采用硬度测试、室温拉伸试验、扫描电镜(SEM)、透射电镜(TEM)和X射线衍射(XRD)等方法研究时效Al-Cu合金固溶态、含θ″相试样、含θ′相试样和含θ相试样在强变形诱导析出相低温回溶过程中的显微组织和力学性能。结果表明：在室温下多向压缩(MAC)变形过程中，随着等效应变的增加，含θ″相试样和含θ′相试样的强度和塑性都显著提高。此外，4种试样的硬度虽然总体上升高，但含θ″相试样和含θ′相试样的硬度在升高过程中出现了一个低谷，与含θ″相试样和含θ′相试样在变形的过程中发生了明显的析出相回溶有关。说明强变形诱导析出相回溶现象在保证强度得到提高的同时，缓解加工硬化引起的脆性，改善塑性。
关键字: Al-Cu合金；强塑性变形；析出相回溶；力学性能
mechanical properties of Al-Cu alloy
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education,
Central South University, Changsha 410083, China）
Abstract:The microstructure and mechanical properties of solution treatment aged Al-Cu alloys, containing θ″, θ′ and θ phases samples severely deformed by repetitive multi-axial compression (MAC) at ambient temperature were investigated by hardness test, tensile test, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The experiment results show that, during the MAC processing, both the strength and ductility of the containing θ″ and θ′ phases specimens increase with increasing the strain. The hardness values of four specimens gradually increase during MAC, the hardness values of specimens containing θ″ and θ′ phases show an ephemeral decrease, which overall increase after MAC. These two unusual phenomena can be ascribed to the profound re-dissolution of θ" and θ′ phases induced by severe plastic deformation. The ductility of severe plastic deformation (SPD) materials is considerably improved due to the re-dissolution of precipitated phases with guaranted amelioration of strength.
Key words: Al-Cu alloy; severe plastic deformation; re-dissolution of precipitated phases; mechanical property
