高位错密度对Al-Cu-Li合金板材蠕变时效响应和力学性能的影响

High density dislocations enhance creep ageing response and mechanical properties in 2195 alloy sheet

魏硕 ¹马培培 ²陈龙辉 ¹杨建使 ¹湛利华 ³刘春辉¹

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作者信息

1. Light Alloy Research Institute,Central South University,Changsha 410083,China;State Key Laboratory of Precision Manufacturing for Extreme Service Performance,Central South University,Changsha 410083,China;School of Mechanical and Electrical Engineering,Central South University,Changsha 410083,China
2. Advancd Research Center,Central South University,Changsha 410083,China Light Alloy Research
3. Light Alloy Research Institute,Central South University,Changsha 410083,China;State Key Laboratory of Precision Manufacturing for Extreme Service Performance,Central South University,Changsha 410083,China
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摘要

由于传统处理工艺下Al-Cu-Li合金的蠕变应变非常低,导致Al-Cu-Li合金壁板构件蠕变时效成形的难度大幅度增加.因此,提高Al-Cu-Li合金蠕变成形性是一个亟需解决的问题.本文详细地研究了低温下施加大预变形(LPD)和室温下施加大预变形对2195 Al-Cu-Li合金板材蠕变时效响应的影响.利用X射线衍射和透射电子显微镜揭示了LPD 合金蠕变时效过程中的位错和析出相的演变规律.通过在液氮温度下进行轧制,获得了具有80%预变形且无边缘开裂的高质量2195合金板材.然而,板材在室温轧制过程中出现了严重的边缘开裂.此外,通过引入高位错密度(位错密度在1.4×1015 m-2以上),2195 Al-Cu-Li合金的蠕变成形性和时效后的强度得到了协同提升.与传统的T3态合金相比,在160℃和150 MPa下,LPD 合金的蠕变应变和时效后的强度分别提高了4～6倍和30～50 MPa,但是伸长率有所降低.LPD合金中位错多以位错缠结的组态存在,但是促进了细小T1相均匀析出.

Abstract

The creep strain of conventionally treated 2195 alloy is very low,increasing the difficulty of manufacturing Al-Cu-Li alloy sheet parts by creep age forming.Therefore,finding a solution to improve the creep formability of Al-Cu-Li alloy is vital.A thorough comparison of the effects of cryo-deformation and ambient temperature large pre-deformation(LPD)on the creep ageing response in the 2195 alloy sheet at 160℃with different stresses has been made.The evolution of dislocations and precipitates during creep ageing of LPD alloys are revealed by X-ray diffraction and transmission electron microscopy.High-quality 2195 alloy sheet largely pre-deformed by 80%without edge-cracking is obtained by cryo-rolling at liquid nitrogen temperature,while severe edge-cracking occurs during room temperature rolling.The creep formability and strength of the 2195 alloy are both enhanced by introducing pre-existing dislocations with a density over 1.4×1015 m-2.At 160℃and 150 MPa,creep strain and creep-aged strength generally increases by 4-6 times and 30-50 MPa in the LPD sample,respectively,compared to conventional T3 alloy counterpart.The elongation of creep-aged LPD sample is low but remains relevant for application.The high-density dislocations,though existing in the form of dislocation tangles,promote the formation of refined T1 precipitates with a uniform dispersion.

关键词

蠕变时效/Al-Cu-Li合金/高位错密度/低温轧制/位错强化

Key words

creep ageing/Al-Cu-Li alloy/high dislocation density/cryogenic rolling/dislocation strengthening

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基金项目

National Natural Science Foundation of China(52274404)

National Natural Science Foundation of China(52305441)

National Natural Science Foundation of China(U22A20190)

Natural Science Foundation of Hunan Province,China(2022JJ20065)

Natural Science Foundation of Hunan Province,China(2023JJ40739)

Science and Technology Innovation Program of Hunan Province,China(2022RC1001)

Fundamental Research Funds for the Central Universities,China(2023ZZTS0972)

National Key R&D Program of China(2021YFB3400903)

出版年

2024

中南大学学报(英文版)

中南大学

中南大学学报(英文版)

CSTPCDEI

影响因子：0.47

ISSN：2095-2899

参考文献量7

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