Microstructure homogeneity regulation of 7050 aluminum forgings by surface cumulative plastic deformation
(1. School of Mechanical Engineering, Yanshan University, Qinhuangdao 066004, China;
2. State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha 410083, China;
3. State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China)
2. State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha 410083, China;
3. State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China)
Abstract: To regulate the microstructure homogeneity of large aluminum structural forgings for aircraft, the surface cumulative plastic deformation was proposed. The microstructure of 7050 aluminum forgings after the surface cumulative plastic deformation was investigated by electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The results showed that the microstructure evolution of 7050 aluminum forgings was more sensitive to the deformation temperature than the strain rate. The dislocation density continued to increase with the decrease of the deformation temperature and the increase of the strain rate. Dislocation density and stored energy were accumulated by the surface cumulative plastic deformation. Besides, a static recrystallization (SRX) model of 7050 aluminum forgings was established. The SRX volume fraction calculated by this model was in good agreement with the experimental results, which indicated that the model could accurately describe the SRX behavior of 7050 aluminum forgings during the surface cumulative plastic deformation.
Key words: microstructure homogeneity regulation; surface cumulative plastic deformation; dislocation density; static recrystallization model