铸态2219铝合金热压缩变形组织演变规律

为解决2219铝合金微观组织粗大、第二相分布不均的问题,开展了对铸态2219铝合金热压缩变形组织演变规律的研究。研究结果表明,经热压缩变形后,铸态2219铝合金组织中粗大的晶粒及连续网状分布的残余结晶相被打碎,经热处理后形成了均匀的再结晶组织。随着变形温度的升高,晶粒组织粗化,但Al2Cu相的分布更细小、均匀;随着变形量的增大,晶粒组织逐渐细化,晶粒大小分布也更均匀,且Al2Cu相也随变形量的增加破碎得更充分,分布更细小、均匀。在大直径铸锭锻造开坯过程中,为了获得Al2Cu相细化分布的组织,变形温度应控制在420℃以上,单次变形量不应低于50%。延长锻后保温时间不会显著影响材料的显微组织,因此,在锻造开坯过程中,为了保证合理的变形温度区间,可以采用回炉加热多火次锻造的方式。

Microstructure evolution law of as-cast 2219 aluminum alloy in hot compression deformation

In order to solve the problems of coarse microstructure and uneven distribution of the second phase in 2219 aluminum alloy,the microstructure evolution laws during hot compression deformation of as-cast 2219 aluminum alloy were studied.The results show that after hot compression deformation,the coarse grains and the residual crystalline phase distributed as continuous network in the as-cast 2219 aluminum alloy structure are broken,and the uniform recrystallization structure is formed after heat treatment.With the increasing of deformation temperature,the grain structure is coarser,but the distribution of Al2Cu phase is more fine and uniform.With the increasing of deformation amount,the grain structure is gradually refined,the grain size distribution is more uniform,and Al2Cu phase is also broken more fully and the distribution is small and uniform.Furthermore,during the forging and cogging process of large diameter ingot,in order to obtain microstructure with uniform and fine Al2Cu phase,the deformation temperature should be controlled above 420℃,and the single deformation amount should not be less than 50%.In addition,the microstructure of material is not significantly affected by extending the holding time after forging.Thus,during the forging and cogging process,the method of reheating and forging with multiple fires is used to ensure the reasonable deformation temperature range.