超高强度7A36铝合金挤压管材热处理工艺研究  

Heat treatment of ultrahigh strength 7A36 aluminum alloy extruded tube

作　　者：李惠曲 邢清源 饶茂 张景亮 臧金鑫 LI Huiqu;XING Qingyuan;RAO Mao;ZHANG Jingliang;ZANG Jinxin(AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China;Beijing Engineering Research Center of Advanced Aluminum Alloys and Applications,Beijing 100095,China;Southwest Aluminum(Group)Co.,Ltd.,Chongqing 401326,China)

机构地区：[1]中国航发北京航空材料研究院,北京100095 [2]北京市先进铝合金材料及应用工程技术研究中心,北京100095 [3]西南铝业(集团)有限责任公司,重庆401326

出　　处：《材料工程》2023年第4期113-121,共9页Journal of Materials Engineering

摘　　要：针对工业化生产条件下制备的?250 mm×20 mm和?340 mm×30 mm两种规格的7A36铝合金挤压管材,开展单级/双级固溶工艺和110~135℃下的单级时效-拉伸性能曲线研究,并采用优选的热处理工艺,对两种规格管材的拉伸性能进行对比研究。采用差热分析仪测试相转变温度,利用金相显微镜、扫描电镜和透射电镜进行显微组织与拉伸断口观察。结果表明:7A36合金管材在优选的热处理工艺下,其抗拉强度、屈服强度和伸长率分别可达696,655 MPa和14.0%;相比常规的半连续铸造(direct chill casting, DC)铸锭+大挤压比工艺,采用锻造铸锭+常规热挤压工艺,合金管材表现出晶粒和晶界/晶内析出相尺寸更小以及晶界无沉淀析出带(precipitation free zone, PFZ)更窄的组织特征,该组织特征是影响强度性能的主要原因;同时,该合金具有较高的淬火敏感性,固溶处理过程中,易在富Fe相附近诱发淬火微裂纹,显著影响合金管材的伸长率。The single-stage&two-stage solution and the single aging-tensile property curves at 110-135℃were studied by using the 7A36 aluminum alloy extruded tube of∅250 mm×20 mm and∅340 mm×30 mm under industrial production conditions.The optimal heat treatment was adopted to compare the tensile properties of two kinds of aluminum alloy extruded tube.The phase transition temperature was measured by DSC,and the microstructure and tensile fracture were observed by OM,SEM and TEM.The results show that the tensile strength,yield strength and elongation of 7A36 alloy extruded tube can reach 696,655 MPa and 14.0%,respectively,under the optimal heat treatment.Compared with the process of direct chill casting(DC)ingot&extrusion with high extrusion ratio,the size of grain and precipitated phase is smaller,the width of precipitation free zone is narrower under the process of forging ingot&conventional extrusion,which significantly affects the strength.At the same time,the alloy shows high quenching sensitivity.During solution treatment,quenching micro-cracks are easily induced near Fe-rich phase,which significantly affects the elongation of alloy extruded tube.

关 键 词：超高强度铝合金 挤压管材 热处理 微观组织 

分 类 号：TG146.2[一般工业技术—材料科学与工程]