均匀化处理对铸态Al-4.51Zn-1.77Mg合金组织的影响  

Effect of homogenization treatment on microstructure of as-cast Al-4.51Zn-1.77Mg alloy

作　　者：石峰[1] 张智超[1] 王旭[1] 吴明[2] 

机构地区：[1]辽宁石油化工大学机械工程学院,辽宁抚顺113001 [2]辽宁石油化工大学石油天然气工程学院,辽宁抚顺113001

出　　处：《材料热处理学报》2017年第9期58-63,共6页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51574147);辽宁省自然科学基金指导计划(201602474)

摘　　要：研究了铸态Al-4.51Zn-1.77Mg合金在不同均匀化工艺条件下的显微组织的演变规律。结果表明:铸态Al-4.51Zn-1.77Mg合金的DSC曲线在476℃附近出现明显的吸热峰;(460~510℃)×24 h均匀化处理后,476℃附近的吸热峰消失。铸态合金晶粒之间包围着大量的枝晶网络,枝晶臂之间存在着大量的非平衡共晶。随均匀化温度的升高,非平衡共晶逐渐回溶到基体中;高于480℃时,晶粒内部和晶界处开始出现形状不规则的复熔粒子,合金出现过烧。在470℃进行均匀化处理,1 h后大部分第二相已回溶到基体中,随均匀化时间的延长,第二相含量逐渐减少;但24 h后,随时间延长第二相含量无明显变化。根据合金的均匀化动力学方程计算出适合实验合金的均匀化制度为470℃×26 h,与实验结果基本相符。Effect of homogenization treatment on microstructure of as-cast Al-4.51Zn-1.77 Mg alloy was studied.The results show that the DSC curve of the as-cast Al-4.51Zn-1.77 Mg alloy has an obvious endothermic peak near 476 ℃,and after homogenization treatment at 460-510 ℃ for 24 h,the endothermic peak near 476 ℃ disappears.A large number of dendritic networks distribute between the grains and a large number of non-equilibrium eutectic exists in the dendrite arms.With the increasing of the homogenization temperature,the non-equilibrium eutectic gradually dissolves into the matrix,and some irregular particles form in the grains and at grain boundaries when the homogenization temperature is higher than 480 ℃,which indicate that over-burning occurs in the alloy.After homogenization at470 ℃ for 1 h,most of the second phase dissolves into the matrix,and the amount of the second phase decreases with the increasing of the homogenization time,but does not change obviously after homogenization for over 24 h.According to the homogenization kinetic equation of the alloy,the suitable homogenization treatment of the experimental alloy is 470 ℃ × 26 h,which is consistent with the experimental results.

关 键 词：铝合金 均匀化 显微组织 非平衡共晶 

分 类 号：TG146.2[一般工业技术—材料科学与工程]