2026铝合金热变形及热处理过程中的微观组织演变

摘要

研究2026铝合金在温度为300-450℃和应变速率为0.01-10 s-1的变形条件与固溶时效热处理后微观组织之间的关系.结果表明:热处理后的再结晶和析出特性与热变形时的温度补偿应变速率Z有关.在低Z条件下,热处理后会形成少量细小的再结晶晶粒,热变形过程产生的高角度亚晶粒和粗大析出物被保留下来;高Z条件下,热处理后会产生大量细小等轴晶再结晶晶粒,热变形过程产生的高密度晶胞和相对细小的动态析出物被热处理后完整的亚晶粒和相对粗化的析出物所替代.热处理后的平均再结晶晶粒尺寸随着Z值的增加而减小.建立两者的定量关系式.%2026 aluminum alloy was compressed in a temperature range of 300-450 ℃ and strain rate range of 0.01-10 s-1. The correlation between compression conditions and microstructural evolution after solution and aging heat treatment was investigated. It is found that the recrystallization and precipitation behavior after heat treatment are associated with the temperature compensated strain rate Z value during hot deformation. Under low Z parameter condition, a small quantity of fine recrystallized grains are formed, and the well formed subgrains with clean high-angle boundaries and coarse precipitates seem to be remained during heat treatment. Under high Z parameter condition, a large number of fine equiaxed recrystallized grains are produced, and a high dislocation density with poorly developed cellularity and considerable fine dynamic precipitates are replaced by the well formed subgrains and relatively coarse precipitates after heat treatment. The average recrystallized grain size after heat treatment decreases with increasing Z value and a quantitative relation between the average grain size and the Z value is obtained.