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采用金相显微镜和透射电子显微镜研究了含钪Al-Zn-Mg-Cu-Zr系铝合金组织的再结晶,测试了不同温度下退火1h合金的硬度。结果表明:含0.20%Sc的7xxx系铝合金(冷变形量50%)的再结晶起始温度为475℃,再结晶终了温度为525℃。合金在均匀化以及热加工过程中析出细小、弥散的二次A l3(Sc,Zr)粒子钉扎位错、亚晶界和晶界,使回复过程中的位错运动受阻,保持基体内较高的位错的密度,阻碍加热时位错重新排列呈亚晶界以及更进一步发展成大角度晶界的过程;阻碍了再结晶核心长大过程,阻碍大角度晶界的迁移,从而提高再结晶温度。
The microstructure of Al-Zn-Mg-Cu-Zr aluminum alloy containing scandium was studied by means of optical microscope and transmission electron microscope. The hardness of the alloy annealed at different temperatures for 1h was tested. The results show that the starting temperature of recrystallization of 7xxx aluminum alloy containing 0.20% Sc (cold deformation 50%) is 475 ℃ and the recrystallization temperature is 525 ℃. In the process of homogenization and thermal processing, the alloy precipitates small and diffused secondary Al 3 (Sc, Zr) particles to pin dislocations, subgrain boundaries and grain boundaries, which hinders the dislocation movement in the recovery process and keeps the matrix more The high density of dislocations hinders the rearrangement of dislocations in heating to subgrain boundaries and the further development of large-angle grain boundaries. This hinders the growth of recrystallized nuclei and hinder the migration of large-angle grain boundaries, Crystallization temperature.