预处理对喷射沉积Al-Cu-Li合金中Al_(3)Zr粒子析出及再结晶行为的影响

Effect of pretreatment on precipitation of Al_(3)Zr dispersoids and recrystallization behavior of spray deposited Al-Cu-Li alloy

本文为探究如何调控喷射沉积Al-Cu-Li合金中Al_(3)Zr粒子的析出以及其析出机制,通过扫描电镜、透射电镜和电子背散射衍射研究了预处理对喷射沉积Al-Cu-Li合金中Al_(3)Zr粒子的析出行为及其对再结晶的影响。研究结果表明,喷射沉积Al-Cu-Li合金中Al_(3)Zr粒子存在分布不均匀,其粒子数量密度在Zr原子过饱和度高的晶内更高,在过饱和度低的晶界附近更低;晶界附近和晶内均存在局部无沉淀析出带,且晶界附近存在少量粒子线性团簇。在均匀化过程中Zr原子与位错攀移之间发生交互作用使得Al3Zr粒子析出。在均匀化前热变形预处理增加了基体中位错数量进而促进了Al_(3)Zr粒子析出,改善了粒子分布,抑制了局部无沉淀析出带。相比于(573 K/12 h)退火预处理和673 K下压缩10%预处理,673 K下压缩30%预处理试样中Al3Zr粒子密度更高,分布更均匀,尺寸更小。经过热压缩和固溶处理后,3种热压缩试样大角度晶界占比分别为30.3%、21.6%和17.3%。本研究将为喷射沉积Al-Cu-Li合金的研发提供依据。

The effects of pretreatment on the precipitation behavior of Al_(3)Zr precipitates and the recrystallization of spray-deposited Al-Cu-Li alloy were investigated by scanning electron microscopy,transmission electron microscopy and electron backscatter diffraction.It was found that the distribution of Al3Zr dispersoids in the spray-deposited Al-Cu-Li alloy was heterogeneous.The dispersoid number density is higher in the intragranular and lower near the grain boundaries.The precipitation-free zones are distributed in the intragranular and near the grain boundaries,while a small number of linear clusters are distributed near the grain boundaries.During the homogenization process,the interaction between Zr atoms and dislocation climb caused the precipitation of Al_(3)Zr dispersoids by fast pipe diffusion.Pretreatment of thermal deformation before homogenization increased the number of dislocations in the matrix,promoted the precipitation of Al_(3)Zr dispersoids,inhibited local PFZs,improved the particle distribution,and uniformly distributed Al_(3)Zr dispersoids.After compression by 30% at 673 K,compared with annealing at 573 K for 12 h and compression by 10% at 673 K,the Al_(3)Zr dispersoids have higher number density,more uniform distribution,and smaller size.After hot compression and solution treatment,the percentages of HAGBs in the three hot compression samples were 30.3%,21.6%,and 17.3%,respectively.