Improvement of strength and ductility for a 6056 aluminum alloy achieved by a combination of equal-channel angular pressing and aging treatment
Improvement of strength and ductility for a 6056 aluminum alloy achieved by a combination of equal-channel angular pressing and aging treatment
复制标题
DOI：
10.1007/s10853-010-4544-y
复制
发表时间：
2010-09-01
影响因子：
4.5
通讯作者：
Halle, Thorsten
中科院分区：
文献类型：
--
作者：
Hockauf, Kristin;Meyer, Lothar W.;Halle, Thorsten
为了提高强度和保持适度的延展性，对6056 Al-Mg-Si-(Cu)合金进行了等径角挤压（ECAP）和时效处理。该方法已被证明对于固溶条件下的少量ECAP通道和随后的时效处理是最有效的，时效处理的时间安排一方面使沉淀硬化达到峰值强度，另一方面使微观组织在开始软化之前恢复。本文将讨论后ecap时效过程中硬度的演变以及时效温度和时效时间对强度和延性的影响。通过低压扫描透射电子显微镜，揭示了其潜在的微观结构特征，包括位错结构和沉淀特征。研究发现，峰值时效，特别是在低时效温度下，适合于获得期望的高强度组合，而在稍欠时效的条件下，塑性最好，但要牺牲一定的强度。与初始峰时效条件相比，经过两次ECAP处理后，在150℃的峰值时效条件下，强度提高了27%，延展性达到6.5%。
Incited by the aim of improving the strength and preserving a moderate ductility, the promising approach of a combined equal-channel angular pressing (ECAP) and aging treatment was applied to the 6056 Al-Mg-Si-(Cu) alloy. This method has been proven to be most effective for a small number of ECAP passes in the solid-solution condition and a following aging treatment, which is timed to enable precipitation hardening up to the peak strength on the one hand and microstructural recovery just before the onset of softening on the other hand. In this work, the evolution of hardness during post-ECAP aging and the effect of aging temperature and time on strength and ductility will be discussed. By means of low-voltage scanning transmission electron microscopy, the underlying microstructural features in terms of dislocation structure and precipitation characteristics will be presented. It has been found that peak aging especially at low-aging temperatures is suitable for achieving the desired high-strength combination, whereas-on the expense of some percent in the strengthening-the ductility is best in slightly underaged conditions. Compared to the initial peak-aged condition, an increase in strength of 27%, combined with a moderate ductility of 6.5% uniform elongation was achieved for peak aging at 150 A degrees C after two passes of ECAP.