一种新型Al-Zn-Mg-Cu系铝合金的均匀化工艺研究

Investigation of Homogenization Treatment on New Al-Zn-Mg-Cu Aluminum Alloy

采用拉伸性能测试、硬度测试、DSC分析、光学显微镜观察、扫描电镜观察（SEM）和透射电镜观察（TEM）等分析方法，研究了单、双级均匀化工艺对一种新型Al-Zn—Mg—Cu合金组织性能的影响及合金的过烧温度。结果表明，采用常规半连续铸造方法生产的该合金铸坯的过烧温度在480℃左右。随均匀化温度的升高，铸造组织中的非平衡共晶相逐渐溶人基体，均匀化温度达到450℃以上时，枝晶组织基本消失，基体固溶度随均匀化温度的升高而增大。在400℃左右对铸锭进行预处理，可促进第二相Al3Zr均匀弥散析出，抑制随后热加工过程中的再结晶，从而细化晶粒，并改善合金工艺塑性。确定该新型Al—Zn—Mg—Cu合金的均匀化工艺为400～420℃／12h＋470℃／36h。

The effect of homogenization treatment on a new Al-Zn-Mg-Cu alloy was studied by tensile test, hardness test, optical microscopy, SEM and TEM to investigate the property. The result point out that the overheat temperature of the new alloy producing by semi-continuous casting is 480℃. With the homogenization temperature increasing, the casting of the mierostrueture of Non-equilibrium phase gradually dissolved into matrix. When the temperature reached 450℃ , the dendritic mierostructure disappeared and the solid solution limit of the matrix raised with the homogenization temperature increasing. It would be benefited for the second phase-Al3Zr dispersion on the pretreatment of the homogenization temperature, which restrained the recrystallization and improve the plastic technology. the propitious homogenization treatment of the new alloy is 400 - 420℃/12h ＋ 470℃/36h.