Retrogression and Reaging Applied to Warm Forming of High-Strength Aluminum Alloy AA7075-T6 Sheet
Retrogression and Reaging Applied to Warm Forming of High-Strength Aluminum Alloy AA7075-T6 Sheet
复制标题
DOI：
10.1007/s11661-018-5084-3
复制
发表时间：
2019-01
期刊：
影响因子：
--
通讯作者：
T. Ivanoff;J. Carter;L. Hector;E. Taleff
中科院分区：
文献类型：
--
作者：
T. Ivanoff;J. Carter;L. Hector;E. Taleff
本研究介绍了回归成形，一种新的高强度铝合金，如AA 7075-T6温成形方法。回归成形结合了回归热处理和同时在约200 °C下的温成形，以改善AA 7075-T6的室温延展性，拉伸约10%，然后可以使用汽车烤漆循环来恢复接近峰值时效的强度。实验数据表明，在200 °C下的回归成形提供了20%的拉伸延展性，大约是室温的两倍，并且随后通过模拟烤漆进行的再时效将硬度恢复到原始峰值时效（T6）硬度的10%以内。为了探索回归成形概念，表征了来自不同供应商的两种AA 7075-T6板材在200 °C和350 °C之间的回归行为。确定了适合于同时温成形的回归处理的时间和温度，并测量了在这些条件下的拉伸塑性。测量了高温变形（高达520 °C）期间的拉伸塑性，并与回归成形条件下的拉伸塑性进行了比较。在460 °C至520 °C的温度下的塑性流动由位错爬升控制的蠕变控制，这是一种不同于在回归形成条件下观察到的行为的机制。
This study introduces retrogression forming, a new warm-forming methodology for high-strength aluminum alloys such as AA7075-T6. Retrogression forming combines a retrogression heat treatment with simultaneous warm forming at approximately 200 °C to improve upon the room-temperature ductility of AA7075-T6, approximately 10 pct in tension, and can then use the automotive paint-bake cycle to restore nearly peak-aged strength. Experimental data indicate that retrogression forming at 200 °C provides a tensile ductility of 20 pct, approximately double that of room temperature, and that subsequent reaging by a simulated paint bake restores hardness to within 10 pct of the original peak-aged (T6) hardness. To explore the retrogression-forming concept, the retrogression behaviors of two AA7075-T6 sheet materials from different suppliers are characterized between 200 °C and 350 °C. The times and temperatures of retrogression treatments suitable for simultaneous warm forming are determined, and tensile ductilities under these conditions are measured. Tensile ductilities during high-temperature deformation (up to 520 °C) are measured and compared to those possible under retrogression-forming conditions. Plastic flow at temperatures of 460 °C to 520 °C is governed by dislocation-climb-controlled creep, a mechanism different from the behaviors observed under retrogression-forming conditions.