Formation of a new intermediate phase and its evolution toward θ’ during aging of pre-deformed Al-Cu alloys  

作　　者：Peipei Ma Chunhui Liu Ziyao Ma Lihua Zhan Minghui Huang 

机构地区：[1]Light Alloy Research Institute of Central South University, State Key Laboratory of High-Performance Complex Manufacturing, Central South University, Changsha, 410083, China [2]School of Mechanical and Electrical Engineering, Central South University, Changsha, 410083, China

出　　处：《Journal of Materials Science & Technology》2019年第5期885-890,共6页材料科学技术（英文版）

基　　金：financial support from the National Natural Science Foundation of China (Nos. 51601060, 51235010, 51671086);Natural Science Foundation of Hunan Province (No. 2018JJ3655);the Major Project for Defense Basic Preresearch Program;the National Key R&D Program of China (No. 2017YFB0306300);the National Key Basic Research Development Plan Funded Project of China (No. 2014CB046602);the Innovationdriven Plan in Central South University (No. 2015CX002);the Science and Technology Plan in Hunan Province (No. 2016RS2015);the Fundamental Research Funds for the Central Universities of Central South University (No. 1053320180612)

摘　　要：The frequent occurrence of hitherto unknown phase Pre-θ′-2 and unusual 1.5 cθ′thick θ′precipitate was observed by atomic-resolution scanning transmission electron microscopy in the well-studied Al-Cu alloys. This phenomenon is associated with heterogeneous precipitate nucleation and growth on preexisting dislocations introduced by slight deformation prior to aging. In this study, the precise structure details of Pre-θ′-2 was determined by atomic scale imaging, image simulation based on image forming theories and first principle calculations. Pre-θ′-2 has a well-defined ordered structure sandwiched between two 2 aAl(~1.5 cθ′) spaced Cu layers on {200}Alplanes. The strong structural similarities between Pre-θ′-2 and 1.5 cθ′ thick θ′ in terms of interfacial structure and thickness, coupled with energetic calculations and preliminary in-situ observations, lead us to propose a new precipitation path toward key strengthening phase θ′The frequent occurrence of hitherto unknown phase Pre-θ’-2 and unusual 1.5 cθ’ thick θ’ precipitate was observed by atomic-resolution scanning transmission electron microscopy in the well-studied Al-Cu alloys. This phenomenon is associated with heterogeneous precipitate nucleation and growth on preexisting dislocations introduced by slight deformation prior to aging. In this study, the precise structure details of Pre-θ’-2 was determined by atomic scale imaging, image simulation based on image forming theories and first principle calculations. Pre-θ’-2 has a well-defined ordered structure sandwiched between two 2 aAl(～1.5 cθ’) spaced Cu layers on {200}Alplanes. The strong structural similarities between Pre-θ’-2 and 1.5 cθ’ thick θ’ in terms of interfacial structure and thickness, coupled with energetic calculations and preliminary in-situ observations, lead us to propose a new precipitation path toward key strengthening phase θ’.

关 键 词：Aluminum ALLOYS PRECIPITATION DEFORMATION Age-harde ning 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG156.92[金属学及工艺—金属材料]