2196铝锂合金的淬火敏感性及析出动力学  

Quenching sensitivity and precipitation kinetics of 2196 alloy

作　　者：李响 李红英[1,4] 刘锦勋 肖翔 林海涛 王燕 郑子樵[1] LI Xiang;LI Hongying;LIU Jinxun;XIAO Xiang;LIN Haitao;WANG Yan;ZHENG Ziqiao(School of Materials Science and Engineering,Central South University,Changsha 410083,China;China Aluminum Materials Application Research Institute Co.,Ltd.,Beijing 102209,China;Southwest Aluminum(Group)Co.,Ltd.,Chongqing 401326,China;State Key Laboratory of Lightweight High-Strength Structural Materials,Central South University,Changsha 410083,China)

机构地区：[1]中南大学材料科学与工程学院,长沙410083 [2]中铝材料应用研究院有限公司,北京102209 [3]西南铝业(集团)有限责任公司,重庆401326 [4]中南大学轻质高强结构材料国家级重点实验室,长沙410083

出　　处：《中国有色金属学报》2024年第5期1475-1485,共11页The Chinese Journal of Nonferrous Metals

摘　　要：采用分级淬火法测定了2196合金挤压型材的时间−温度−转化率(TTT)和时间−温度−性能(TTP)曲线,结合电子探针显微分析(EPMA)、扫描电镜(SEM)、透射电镜(TEM)和Johnson-Mehl-Avrami(JMA)方程研究了2196合金在等温处理过程中的组织转变和析出动力学。结果表明:2196合金型材的鼻尖温度为375℃,孕育期为0.9 s,淬火敏感区间为300~425℃;在等温处理过程中,过饱和固溶体分解析出粗大的T_(1)相,且在375℃附近的析出速率最大;随着保温时间的延长,T_(1)相聚集并长大,时效后纳米析出相减少,无沉淀析出区变宽,导致合金力学性能显著下降;根据析出动力学方程拟合出的“S”形曲线,解释了合金在375℃附近淬火敏感性最大的原因,分析了在淬火敏感区间第二相的析出规律。The time−temperature−transformation(TTT)and time−temperature−property(TTP)curves of 2196 alloy extruded profiles were measured by interruption quenching method.The microstructure transformation and precipitation kinetics of 2196 alloy during isothermal treatment were studied by electron probe microanalysis(EPMA),scanning electron microscopy(SEM),transmission electron microscopy(TEM)and Johnson-Mehl-Avrami(JMA)equation.The results show that the nose temperature of 2196 alloy profiles is 375℃,the incubation period is 0.9 s,and the quenching sensitive range is 300−425℃.During the isothermal treatment,the coarse precipitate decomposed from the supersaturated solid solution is T_(1) phase,and the precipitation rate of the second phase is the largest near 375℃.With the extension of holding time,the T_(1) phase aggregates and grows,and the nano-precipitated phase decreases after aging,and the precipitation free zone(PFZ)becomes wider,resulting in a significant decrease in mechanical properties.According to the S-shape curve fitted by the precipitation kinetic equation,the reason for the maximum quenching sensitivity of the alloy near 375℃is explained,and the precipitation law of the second phase of the alloy in the quenching sensitive range is analyzed.

关 键 词：2196铝锂合金 时间−温度−转化率(TTT)曲线 时间−温度−性能(TTP)曲线 淬火敏感性 析出动力学 

分 类 号：TG146.2[一般工业技术—材料科学与工程]