Al-9.0Zn-2.5Mg-1.5Cu-0.15Zr-0.2Sc合金淬火性能及TTT和TTP曲线（英文）  

TTT and TTP Diagrams of Quenching Sensitivity of Al-9.0Zn-2.5Mg-1.5Cu-0.15Zr-0.2Sc Alloy

作　　者：戴晓元[1] 熊超宇 李妮[1] 罗奕兵[1] Dai Xiaoyuan;Xiong Chaoyu;Li Ni;Luo Yibing(Key Laboratory of Lightweight of Engineering Vehicle and Reliability Technology,Changsha University of Science and Technology,Changsha 410114,China)

机构地区：[1]长沙理工大学工程车辆轻量化与可靠性技术重点实验室,湖南长沙410114

出　　处：《稀有金属材料与工程》2019年第3期721-727,共7页Rare Metal Materials and Engineering

基　　金：Key Laboratory of Lightweight and Reliability Technology for Engineering Vehicle,Education Department of Hunan Province(2016kfjj06)

摘　　要：通过分级淬火处理得到Al-9.0Zn-2.5Mg-l.5Cu-0.15Zr-0.2Sc铝合金的时间-温度-转变(TTT)曲线和时间-温度-性能(TTP)曲线,采用透射电子显微镜(TEM)、差示扫描量热仪(DSC)和X射线衍射(XRD)对合金进行了相变分析。结果表明:在一定的温度下延长保温时间会导致试样的电导率增加,硬度降低。显微组织观察表明,随着保温时间的增加,许多大型杆状平衡相η(MgZn2)会在基体中析出并快速生长,导致淬火过程中溶质损失,削弱了随后的时效强化效果。η粒子沉淀析出的主要原因是溶质原子的快速扩散和强大的相变驱动力。淬火敏感温度范围为270～390℃。因此,在淬火敏感温度范围内,需适当提高冷却速度以获得较高的力学性能。其他温度范围内应考虑适当降低冷却速度以控制残余应力。The time-temperature-transformation(TTT) curve and time-temperature-property(TTP) curve of Al-9.0 Zn-2.5 Mg-1.5 Cu-0.15 Zr-0.2 Sc alloy were determined by an interrupted quenching technique. Phase transformations were investigated by transmission electron microscope(TEM), differential scanning calorimetry(DSC) and X-ray diffraction(XRD). The result shows that when the holding time is prolonged at a certain temperature, the electro-conductivity of the specimens tends to increase and the hardness will decreases. Microstructure observation indicates that as the time increases, a lot of large equilibrium rod-shaped η(MgZn2) phases precipitate in the matrix and grow rapidly, which results in the loss of solutes during the quenching process and weakens the subsequent aging strengthening effect. The main reasons for the precipitation of η particles are the rapid diffusion of solute atoms and the strong driving force for phase transformation.Quenching sensitive temperature range is 270~390℃. Consequently,in the quenching sensitive temperature range,it is necessary to increase the cooling rate properly to obtain high mechanical properties. And in other temperature ranges, the cooling rate should be appropriately lowered to control the residual stress.

关 键 词：Al-9.0Zn-2.5Mg-1.5Cu-0.15Zr-0.2Sc合金 TTT曲线:TTP曲线:无沉淀析出区(PFZ) 

分 类 号：V252[一般工业技术—材料科学与工程]