Aging behavior and mechanical properties of 6013 aluminum alloy processed by severe plastic deformation
(1. School of Materials Science and Engineering, Jiangsu Province Key Laboratory of Materials Tribology,
Jiangsu University, Zhenjiang 212013, China;
2. Department of Materials Science and Engineering,
Norwegian University of Science and Technology, Trondheim 7491, Norway;
3. Center for Advanced Materials, Qatar University, P.O. Box 2713, Doha, Qatar)
Jiangsu University, Zhenjiang 212013, China;
2. Department of Materials Science and Engineering,
Norwegian University of Science and Technology, Trondheim 7491, Norway;
3. Center for Advanced Materials, Qatar University, P.O. Box 2713, Doha, Qatar)
Abstract: Structural features, aging behavior, precipitation kinetics and mechanical properties of a 6013 Al–Mg–Si aluminum alloy subjected to equal channel angular pressing (ECAP) at different temperatures were comparatively investigated with that in conventional static aging by quantitative X-ray diffraction (XRD) measurements, differential scanning calorimetry (DSC) and tensile tests. Average grain sizes measured by XRD are in the range of 66-112 nm while the average dislocation density is in the range of 1.20×1014-1.70×1014 m-2 in the deformed alloy. The DSC analysis reveals that the precipitation kinetics in the deformed alloy is much faster as compared with the peak-aged sample due to the smaller grains and higher dislocation density developed after ECAP. Both the yield strength (YS) and ultimate tensile strength (UTS) are dramatically increased in all the ECAP samples as compared with the undeformed counterparts. The maximum strength appears in the samples ECAP treated at room temperature and the maximum YS is about 1.6 times that of the statically peak-aged sample. The very high strength in the ECAP alloy is suggested to be related to the grain size strengthening and dislocation strengthening, as well as the precipitation strengthening contributing from the dynamic precipitation during ECAP.
Key words: Al-Mg-Si aluminum alloy; severe plastic deformation; equal-channel angular pressing; aging behavior; precipitation kinetics; mechanical properties; strengthening mechanisms