2219铝合金蠕变时效成形过程中的断裂行为  

Fracture behavior in creep aging forming process of aluminum alloy 2219

作　　者：孙找 湛利华 刘健[2] 李先梦[1] 杨有良 SUN Zhao1 , ZHAN Li-hua1, 2,3 , LIU Jian2 , LI Xian-meng1, YANG You-liang2(1. Light Alloy Research Institute, Central South University, Changsha 410083, China; 2. School of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China; 3. State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha 410083, China)

机构地区：[1]中南大学轻合金研究院,湖南长沙410083 [2]中南大学机电工程学院,湖南长沙410083 [3]中南大学高性能复杂制造国家重点实验室,湖南长沙410083

出　　处：《塑性工程学报》2018年第5期284-290,共7页Journal of Plasticity Engineering

基　　金：高性能复杂制造国家重点实验室自主研究课题(zzyjkt2015-05);中南大学“创新驱动计划”项目(2015CX002);高等学校博士学科点专项科研基金(20120162110003);高强铝合金大型复杂构件形性协同制造的科学基础(51235010)

摘　　要：研究了蠕变时效成形过程中2219铝合金的蠕变断裂行为,建立了2219铝合金蠕变时效成形过程中的成形极限图。结果表明：在蠕变时效成形过程中断裂临界应力呈＂S＂形分布,随着蠕变温度的升高,蠕变断裂行为对应力水平的敏感性增加。低温高应力和高温低应力条件下蠕变时效成形过程中断裂行为极易发生,成形工艺条件应避免这些＂濒危区＂。通过采用金相显微镜、扫描电镜观察了2219铝合金蠕变断裂后的微观组织变化,发现合金变形方式主要为位错在晶内的滑移,断裂行为主要受微孔的聚集影响;蠕变温度越高,在晶界处形成的微孔越多,越容易萌生裂纹,而裂纹在强烈滑移处会迅速扩展,从而降低蠕变断裂所需的应力;随着蠕变温度的升高,合金的断裂特征由准解理-韧窝混合型断裂向韧窝断裂转变。The creep fracture behavior of aluminum alloy 2219 during creep aging forming process was studied,and the forming limit diagram of aluminum alloy 2219 during creep aging forming process was established. The results show that the critical fracture stress is＂S＂shape in the creep aging forming process,with the increase of creep temperature,the sensitivity of the creep fracture behavior to stress level increases. Under the condition of low temperature,high stress and high temperature,low stress,the fracture behavior is easy to occur during the process of creep aging,and the forming process condition should avoid these‘endangered areas＇. The microstructures of aluminum alloy 2219 after creep fracture were observed by optical microscopy and scanning electron microscopy（ SEM）. The deformation of the alloy is mainly caused by the dislocation sliping in the crystal,and the fracture is mainly affected by the aggregation of the micropores. The higher the creep temperature is,the more micropores form at the grain boundaries,the easier the initiation of crack is,and the crack in the strong slip expand rapidly,thereby reducing the stress required for creep fracture. With the increase of creep temperature,the characteristic of alloy fracture is changed from quasi-cleavage-dimple fusion to ridge fracture.

关 键 词：2219铝合金 蠕变断裂行为 蠕变成形极限图 断裂临界应力 断裂特征 

分 类 号：TG146.2[一般工业技术—材料科学与工程]