Residual stress relaxation and cyclic deformation behavior of deep rolled AlMg4.5Mn (AA5083) at elevated temperatures
- The cyclic deformation behavior of deep rolled and polished aluminium wrought alloy AlMg4,5Mn in the temperature range 20-300°C has been investigated. Results of quasistatic tension and compression tests of untreated specimens in the temperature range 20-300°C are presented. To characterize the fatigue behavior for stress-controlled tests as a function of test temperature, s-n curves, cyclic deformations curves and mean strains as a function of number of cycles are given. The residual stress- and work hardening states near the surface of deep rolled aluminium alloy AlMg4.5Mn before and after fatigue tests were investigated by X-ray diffraction methods. The investigated AlMn4.5Mn aluminium alloy shows cyclic hardening until fracture at all stress amplitudes in stress-controlled fatigue tests at 25-150°C. With increasing temperature the deformation behavior shifts from cyclic hardening to cyclic softening. Below a certain stress amplitude at a given temperature deep rolling led to a reduction of the plastic strain amplitude as compared to the untreated state through cyclically stable near-surface work hardening as indicated by stable FWHM-values. This reduction in plastic strain amplitude is associated with enhanced fatigue lives. The effectiveness of deep rolling is governed by the cyclic and thermal stability of near-surface work hardening rather than macroscopic compressive residual stresses. Since near-surface work hardening is known to retard crack initiation, deep rolling is also effective in temperature- and stress ranges where macroscopic compressive residual stresses have relaxed almost completely, but where near-surface work hardening prevails. Above certain stress amplitudes and temperatures, deep rolling has no beneficial effect on the fatigue behavior of AlMg4.5Mn. This is a consequence of instable near-surface microstructures, especially instable near-surface work hardening.
Author: | Patiphan Juijerm, Igor Altenberger, Ulf Noster, Berthold Scholtes |
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DOI: | https://doi.org/10.4028/www.scientific.net/MSF.490-491.436 |
Parent Title (English): | Materials Science Forum |
Publisher: | Trans Tech Publications |
Document Type: | conference proceeding (article) |
Language: | English |
Year of first Publication: | 2005 |
Release Date: | 2022/12/01 |
Tag: | deep rolling; high temperature fatigue; residual stress relaxation |
Volume: | 490-491 |
First Page: | 436 |
Last Page: | 441 |
Institutes: | Fakultät Maschinenbau |
Fakultät Maschinenbau / Labor Werkstoffrandschichtanalytik | |
Publication: | Externe Publikationen |
research focus: | Produktion und Systeme |
Licence (German): |