A unified constitutive model for asymmetric tension and compression creep-ageing behaviour of naturally aged Al-Cu-Li alloy

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Title: A unified constitutive model for asymmetric tension and compression creep-ageing behaviour of naturally aged Al-Cu-Li alloy
Authors: Li, Y
Shi, Z
Lin, J
Yang, YL
Rong, Q
Huang, BM
Chung, TF
Tsao, CS
Yang, JR
Balint, DS
Item Type: Journal Article
Abstract: A set of unified constitutive equations is presented that predict the asymmetric tension and compression creep behaviour and recently observed double primary creep of pre - stretched/naturally aged aluminium - cooper - lithium alloy AA2050 - T34. The evolution of the primary micro - and macro - variables related to the precipitation hardening and creep deformation of the alloy during creep age forming (CAF) are analysed and modelled. E quations for the yield strength evolution of the alloy, including an initial reversi on and subsequent strengthening, ar e proposed based on a theory of concurrent dissolution, re - nucleation and growth of precipitates during artificial ageing . We present new observations of so - called double primary creep during the CAF process . This phenomenon is then predicted by introducing effects of interact ing microstructures , including evolving precipitates, diffusing solutes and dislocations , into the sinh - law creep model. In addition, concepts of threshold creep stress 휎 푡 ℎ and a microstructu re - dependant creep variable H , which behave differently under different external stress directions, are proposed and incorporat ed into the creep model . This enables predict ion of the asymmetric tension and compression creep - ageing behaviour of the alloy. Q uanti tative transmission electron microscopy (TEM) and related small - angle X - ray scattering (SAXS) analysis ha ve been carried out for selected creep - aged samples to assist the development and calibration of the constitutive model. A good agreement has been achieved between the experimental results and the model. The model has the potential to be applied to creep age form ing of other heat - treatable aluminium alloys.
Issue Date: 19-Nov-2016
Date of Acceptance: 18-Nov-2016
URI: http://hdl.handle.net/10044/1/42706
DOI: https://dx.doi.org/10.1016/j.ijplas.2016.11.007
ISSN: 1879-2154
Publisher: Elsevier
Start Page: 130
End Page: 149
Journal / Book Title: International Journal of Plasticity
Volume: 89
Copyright Statement: © 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
Sponsor/Funder: CRRC Qingdao Sifang Co.,Ltd
Funder's Grant Number: MESM_P57419
Keywords: Mechanical Engineering & Transports
0905 Civil Engineering
0912 Materials Engineering
0913 Mechanical Engineering
Publication Status: Published
Open Access location: https://dx.doi.org/10.1016/j.ijplas.2016.11.007
Appears in Collections:Faculty of Engineering
Mechanical Engineering
Faculty of Natural Sciences

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