预退火处理对等通道转角挤压双辊铸轧AA3003铝合金显微组织演变的影响

摘要

An AA3003 aluminum alloy prepared by twin-roll casting was modified by a small amount of zirconium. Annealing at 450 °C led to precipitation of coherent Al3Zr phase and a simultaneous co-precipitation of Mn-richα-Al(Mn,Fe)Si phase. Severe plastic deformation by equal channel angular pressing resulted in the grain refinement and increase of microhardness. Observation by electron back-scatter diffraction and in-situ transmission electron microscopy revealed influence of pre-annealing on microstructure changes during post-deformation heat treatment. Dislocation recovery and precipitation ofα-Al(Mn,Fe)Si particles preceded recrystallization at 450 °C in material which was not annealed before deformation. The pre-deformation annealing enabled dynamic recovery during deformation as it depleted the solid solution from Mn atoms. Recrystallization was enhanced by Al3Zr precipitates.%添加少量锆元素对双辊铸轧AA3003铝合金进行改性。在450°C对合金进行退火处理产生Al3Zr析出相，同时出现富Mnα-Al(Mn, Fe)Si相。由等通道转角挤压引起的大塑性变形致使合金的晶粒细化且硬度增加。电子背散射衍射及透射电镜观察结果显示在热处理变形后期预先退火处理对合金显微组织变化的影响。对于变形前未进行退火处理的合金，在450°C退火时，其位错回复和α-Al(Mn, Fe)Si相析出使再结晶提前发生。由于预变形退火使固溶体中 Mn 原子含量降低，因此，在变形过程中对合金进行预变形退火处理会使回复更容易发生。Al3Zr析出相能促进再结晶过程的进行。