不同应力水平对2195-T34 Al-Li合金时效行为的影响机制研究  

Regulation mechanism of aging behavior and mechanical properties of 2195-T34 Al-Li alloy at different stress levels

作　　者：陈非 湛利华 徐永谦 刘春辉 马博林 曾泉清 胡正根 朱文俐 鄢东洋 CHEN Fei;ZHAN Li-hua;XU Yong-qian;LIU Chun-hui;MA Bo-lin;ZENG Quan-qing;HU Zheng-gen;ZHU Wen-li;YAN Dong-yang(Light Alloy Research Institute of Central South University,Changsha 410083,China;School of Mechanical and Electrical Engineering,Central South University,Changsha 410083,China;State Key Laboratory of High-performance Complex Manufacturing,Central South University,Changsha 410083,China;Beijing Institute of Astronautical Systems Engineering,Beijing 100176,China)

机构地区：[1]Light Alloy Research Institute of 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 [4]Beijing Institute of Astronautical Systems Engineering,Beijing 100176,China

出　　处：《Journal of Central South University》2024年第1期11-24,共14页中南大学学报（英文版）

基　　金：Projects(U22A20190, 52175373, 52005516) supported by the National Natural Science Foundation of China;Project(ZZYJKT2021-03) supported by the State Key Laboratory of High Performance Complex Manufacturing,Central South University,China;Project(2020RC4001) supported by the Science and Technology Innovation Program of Hunan Province,China。

摘　　要：研究了不同应力水平下2195-T34 Al-Li合金的时效特性变化。当应力低于材料的高温屈服强度(YS)时,低应力时效(LSA)和无应力时效(SFA)试样的屈服强度和延伸率(EL)相近。当应力超过材料的高温屈服强度时,试样的极限拉伸强度(UTS)和伸长率显著下降,表明应力的增加降低了材料的抗破坏性。透射电子显微镜(TEM)和扫描电子显微镜(SEM)的观察结果表明:应力对材料时效性能的影响归因于内部析出物特征和晶界富铜析出物的共同作用。应力的增加促使铜原子在晶界发生偏析形成富铜析出物,同时促进了晶界无沉淀区(PFZ)的形成,而富铜析出物是脆性相,可作为损伤的起始位置,容易导致裂纹萌生和发展,降低材料的延展性。The effect of aging on the mechanical properties of the 2195-T34 Al-Li alloy at different stress levels was investigated.When the stress was below the high-temperature yield strength(YS),the YS and elongation(EL) of the lowstress aged(LSA) and stress-free aged(SFA) specimens were similar.When the stress exceeded the high-temperature YS,the ultimate tensile stress(UTS) and EL of the specimens(HSA specimens) decreased significantly.This decrease suggested that an increase in stress reduced the damage resistance of the material.Transmission electron microscopy(TEM) and scanning electron microscopy(SEM) observations showed that variations in the effect of stress on the material properties were attributed to the combined effect of internal precipitate characteristics and Cu-rich precipitates at the grain boundary.The increase in stress induced the segregation of Cu atoms at the grain boundaries to form Cu-rich precipitates,facilitating the formation of precipitation-free zones(PFZ) at the grain boundaries.In addition,Cu-rich precipitates could act as damage nucleation sites,reducing the ductility of the material.

关 键 词：铝锂合金 应力水平 时效 力学性能 

分 类 号：TG146.21[一般工业技术—材料科学与工程]