微量元素对Al-7.5Mg-0.5Mn合金临界退火冷却速度的影响

The Effects of Microelements on the Critical Annealing Cool Speed of Al-7. 5 Mg-0. 5 Mn Alloy

利用光学显微镜，电化学测试和腐蚀试验等方法系统地研究了微量元素Cr、Zr、Ti和Cu对Al－7．5Mg－0．5Mn合金热轧板材临界退火冷却速度（CRC）及组织性能的影响。结果表明：Cr和Zr能促进退火过程中β相的均匀析出，明显提高CRC和抗剥蚀性（EC），有利于高Mg合金加工工艺的改善；CU虽能促进β相的均匀分布，促进合金的均匀腐蚀，但对冷却速度不敏感；Ti的作用不明显，甚至对抗蚀性有消极影响。

By means of optical microscopes, galvano-chemistry test, erosion test and other methods, the effects of microelements(such as Cr. Zr, Ti and Cu ) on the critical annealing cool speed and the structure properties of hot-pressed Al-7. 5 Mg-0. 5 Mn alloy plates are studied systematically. The results show that elements Cr and Zr can facilitate the homogeneous precipitation of β phase during annealing process. increase material's CRc and EC obviously, and improve the process of high Mg. alloy; element Cu,although it can facilitate the homogeneous precipitation of β phase and the homogeneous corrosion of alloy, is insensitive to the cooling speed; while the fuction of element Ti is not abvious. it even. yields the negative influence on the corrosion stability.