航空领域用5A90铝锂合金高温变形性能及组织变化规律  

High temperature deformation properties and microstructure variation law of 5A90 Al-Li alloy used in aviation field

作　　者：冯贞伟 蒋少松[2] 康良炜 Feng Zhenwei;Jiang Shaosong;Kang Liangwei(The Second Military Representative Office of the Air Force Equipment Department in Harbin,Harbin 150001,China;National Key Laboratory for Precision Hot Processing of Metals,Harbin Institute of Technology,Harbin 150001,China)

机构地区：[1]空军装备部驻哈尔滨地区第二军事代表室,黑龙江哈尔滨150001 [2]哈尔滨工业大学金属精密热加工国家级重点实验室,黑龙江哈尔滨150001

出　　处：《锻压技术》2024年第9期186-194,共9页Forging & Stamping Technology

摘　　要：对厚度为1.30 mm的5A90铝锂合金薄板在变形温度为340、370、400、430、460和490℃,应变速率为0.0001、0.0005和0.001 s^(-1)变形参数下进行了高温拉伸实验,通过应力-应变曲线探究了其热变形行为,并对拉伸后试样的微观组织和断口形貌进行了观察以研究变形参数对材料微观组织的影响。研究结果表明:高温拉伸时峰值应力随变形温度的增加而减小,随着应变速率的减小而降低;应变速率为0.0005 s^(-1)、变形温度为340℃时5A90铝锂合金的伸长率出现最大峰值,达到68%;伸长率在低应变速率下与温度大致成反比,在0.001 s^(-1)时由于高温变形晶界发生滑动而出现峰值。当温度增加时,组织晶粒随着温度的升高沿单向拉伸方向明显伸长;随着应变速率的降低,晶粒明显长大,由不完全的等轴晶转化为完全的等轴晶。High temperature tensile experiments were conducted on 5A90 Al-Li alloy thin sheet with the thickness of 1.30 mm at the deformation temperatures of 340,370,400,430,460 and 490 ℃ and the strain rates of 0.0001,0.0005 and 0.001 s^(-1),and the deformation behavior was studied by stress-strain curve.Then,the microstructure and fracture morphology of samples after stretching were observed to study the influence of deformation parameters on the microstructure of material.The results show that the peak stress decreases with the increasing of deformation temperature,and decreases with the decreasing of strain rate.When the strain rate is 0.0005 s^(-1) and the temperature is 340 ℃,the maximum elongation of 5A90 Al-Li alloy reaches 68%,and the elongation is inversely proportional to the temperature at the low strain rate.At the strain rate of 0.001 s^(-1),there is a peak value due to the sliding of high temperature deformation grain boundary.When the temperature increases,the grains of microstructure are significantly elongated along the uniaxial stretching direction with the increasing of temperature.In addition,with the decreasing of strain rate,the grain grows up significantly,transforming from the incomplete equiaxed grains to the complete equiaxed grains.

关 键 词：5A90铝锂合金 高温拉伸 显微组织 热变形行为 断口分析 

分 类 号：TG132.3[一般工业技术—材料科学与工程]