7050铝合金回归再时效工艺（RRA）研究

摘要

By improving traditional RRA process practice, industrial RRA heat treatment system for 7050 alloy with thickness of 27mm can be obtained by orthogonal test. That is :pre-aging 120℃/24h, heat up from 120℃ to 190℃ within 20mins, soaks for 60mins, and water cooling to ambient temperature and then re-age 120℃/24h. This practice has been verified with repeat tests and TEM analysis with similar inter-granular microstructure to T6 with fine dispersed phase η’ and quite few phase η. Meanwhile, size and distribution feature of grain boundary precipitations are similar to T74. By this practice, the material could have strength of T6 and anti-corrosion property of T74.%通过对传统RRA处理路线的改进，采用正交试验法得到了27mm厚的7050铝合金可工业化生产的RRA处理的热处理制度，即：预时效120℃/24h＋20min内从120℃加热至190℃并保温60min后强制水冷到室温＋再时效120℃/24h。这种制度经重复性验证及TEM分析，其晶内保持类似于T6状态的显微组织结构，为细小弥散的η＇相和极少量的η相。同时，晶界析出物的大小和分布特征与T74状态的类似，这样既保证了T6状态的强度又具有T74状态的抗蚀性能。