2197(Al-Li)-T851合金的疲劳裂纹萌生与扩展行为研究  

Initiation and Propagation Behavior of Fatigue Cracks in 2197(Al-Li)-T851 Alloy

作　　者：陈圆圆[1] 郑子樵[1] 蔡彪[1] 徐建秋[1] 佘玲娟[1] 李海[2] 

机构地区：[1]中南大学,湖南长沙410083 [2]江苏工业学院,江苏常州213164

出　　处：《稀有金属材料与工程》2011年第11期1926-1930,共5页Rare Metal Materials and Engineering

基　　金：国家重点基础研究发展规划("973"计划)(2005CB623705)

摘　　要：研究了2197-T851合金的疲劳裂纹萌生与扩展特性。结果表明,2197铝锂合金的疲劳裂纹萌生与应力水平有关,在较低应力下,主要萌生在第二相粒子、第二相粒子/基体界面以及表面缺陷处,而在较高应力水平下,还出现沿滑移带和晶界处萌生。裂纹的扩展优先沿有利滑移面,在晶粒间的扩展以沿{111}面的穿晶扩展为主,也有沿小角度晶界扩展的情况,合金具有很好的平面滑移性。裂纹在晶粒内的扩展并非沿一个滑移系的直线扩展而是频繁发生偏折,却始终沿{111}面,可剪切共格相δ'粒子造成晶内扩展路径曲折。The initiation and propagation characteristics of the fatigue cracks were studied for 2197-T851 alloy.The results indicate that fatigue crack initiation is related to stress.Under smaller stress,fatigue cracks mainly initiate from the second phase particles and the interface between the second phase particles and matrix as well as from the surface defect.While with larger stress,fatigue cracks easily initiate from the grain boundary and the slip band.Fatigue cracks grow along the favorable slip plane with priority.When the favorable slip planes in the adjacent grains have an angle,the crack deflects.The coherent δ＇ particles that can be sheared by dislocation result in the crack path meandering in the grain.The cracks grow mainly in transgranular mode along the（111） plane,and also along the small-angle grain boundaries.

关 键 词：2197铝锂合金 裂纹萌生和扩展 EBSD 疲劳断口 

分 类 号：TG146.2[一般工业技术—材料科学与工程]