铸态Al-Zn-Mg-Cu高强铝合金热拉伸力学性能及断裂行为  

Hot Tensile Mechanical Properties and Fracture Behavior of Al-Zn-Mg-Cu High Strength Alloy

作　　者：喻征[1] 赵晓东[1] 李飞[1] 陈慧琴[1] 

机构地区：[1]太原科技大学材料科学与工程学院,太原030024

出　　处：《太原科技大学学报》2015年第4期294-300,共7页Journal of Taiyuan University of Science and Technology

基　　金：国家自然科学基金(51175361)

摘　　要：运用Gleeble-1500D热模拟试验机对铸态Al-Zn-Mg-Cu高强铝合金进行高温拉伸实验,利用光学显微镜（OM）观察断口附近的微观组织,用扫描电子显微镜（SEM）观察断口形貌。结果表明,变形温度在340℃~420℃,应变速率为0.01 s-1时,随着温度升高,峰值应力、峰值应变、断裂应变、断面收缩率、延伸率均下降;变形温度为360℃,应变速率为0.1 s-1~1 s-1时,随着应变速率的增大,峰值应力、峰值应变均增大,断裂应变减小,断面收缩率和延伸率有下降的趋势。该合金高温拉伸过程中的软化机制主要为动态回复。高温拉伸的断口形貌为韧性断裂。断口表面的粗大脆硬相对材料的性能有严重影响。Hot tensile experiments of as-cast Al-Zn-Mg-Cu high strength alloy were carried out by means of a Gleeble-1500 D thermo-mechanical modeling simulator. Microstructures near the fractures and fractography were analyzed by Optical Microscope（ OM） and Scanned Electron Microscope（ SEM）. The results indicate that peak stress,peak strain,fracture strain,area reduction and elongation rate decrease with increasing temperatures in the temperature ranges of 340 ℃ ~ 420 ℃ and strain rate of 0. 01 s- 1. Peak stress and peak strain increase with increasing strain rates; Fracture strain,area reduction and elongation decrease with increasing strain rates. Dynamic recovery dominants during the hot tensile. The mixed fracture of ductile fracture and brittle fracture was observed by analyzed the hot tensile fractography. Coarse and brittle hard phases in the alloy have an important effects on hot tensile properties of the alloy.

关 键 词：AL-ZN-MG-CU合金 高温拉伸 力学性能 断口形貌 

分 类 号：TG359[金属学及工艺—金属压力加工]