scholarly journals Internal Stress and Dislocation Interaction of Plate-Shaped Misfitting Precipitates in Aluminum Alloys

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5811
Author(s):  
Shinji Muraishi
Keyword(s):  
Aluminum Alloys ◽  
Stress Field ◽  
Internal Stress ◽  
Slip Plane ◽  
Motion Vector ◽  
Interaction Force ◽  
Age Hardening ◽  
Dislocation Interaction ◽  
Eshelby Inclusion ◽  
Primary Slip Plane

The fine misfit precipitates in age-hardenable aluminum alloys have important roles due to their excellent age-hardening ability, by their interaction with dislocations. The present study focused on the internal stress field of plate-shaped misfitting precipitates to evaluate their roles in dislocation overcoming the precipitates by means of micromechanics based on Green’s function method. The stress field of misfit precipitates on {001} and {111} habit planes were reproduced by homogeneous misfit strain (eigenstrain) of the precipitate (Eshelby inclusion method), and the dislocation motion vector on the primary slip plane was predicted by the force acted on the dislocation by the Peach–Koehler formula. According to simulation results, the dislocation interaction strongly depends on the stress field and geometry of misfit precipitates; repulsive and attractive forces are operated on the dislocations lying on the primary slip plane when the dislocation approaches the misfit precipitates. The hardening ability of different orientations of precipitation variants was discussed in terms of interaction force acted on the dislocation.

Strong and ductile age-hardening Mg-Al-Ca-Mn alloy that can be extruded as fast as aluminum alloys

2017 ◽  
Vol 130 ◽  
pp. 261-270 ◽  
Author(s):  
T. Nakata ◽  
C. Xu ◽  
R. Ajima ◽  
K. Shimizu ◽  
S. Hanaki ◽  
...  
Keyword(s):  
Aluminum Alloys ◽  
Age Hardening

THE EFFECTS OF ELASTIC STIFFENING ON THE EVOLUTION OF THE STRESS FIELD WITHIN A SPHERICAL ELECTRODE PARTICLE OF LITHIUM-ION BATTERIES

2013 ◽  
Vol 05 (04) ◽  
pp. 1350040 ◽  
Author(s):  
WENBIN ZHOU ◽  
FENG HAO ◽  
DAINING FANG
Keyword(s):  
Stress Field ◽  
Lithium Ion Batteries ◽  
Internal Stress ◽  
Concentration Gradient ◽  
Concentration Field ◽  
Lithium Ion ◽  
Coupling Model ◽  
Ion Concentration ◽  
Hysteresis Phenomenon ◽  
Mechanical Coupling

Poor cyclic performance of lithium-ion batteries is calling for efforts to study its capacity attenuation mechanism. The internal stress field produced in the lithium-ion battery during its charging and discharging process is a major factor for its capacity attenuation, research on it appears especially important. We established an electrochemical –mechanical coupling model with the consideration of the influence of elastic stiffening on diffusion for graphite anode materials. The results show that the inner stress field strongly depends on the lithium-ion concentration field, greater concentration gradients lead to greater stresses. The evolution of the stress field is similar to that of the concentration gradient but lags behind it, which shows hysteresis phenomenon. Elastic stiffening can lower the concentration gradient and increase elastic modulus, which are two major factors influencing the inner stress field. We conclude that the latter is more dominant compared to the former, and elastic stiffening acts to increasing the internal stress.

scholarly journals Recent advances in the metallurgy of aluminum alloys. Part II: Age hardening

2018 ◽  
Vol 19 (8) ◽  
pp. 688-709 ◽  
Author(s):  
Christophe Sigli ◽  
Frédéric De Geuser ◽  
Alexis Deschamps ◽  
Joël Lépinoux ◽  
Michel Perez
Keyword(s):  
Aluminum Alloys ◽  
Age Hardening ◽  
Recent Advances

Retrogression and Re-aging Heat Treatment: AA7XXX Aluminum Alloys

2019 ◽  
Author(s):  
V. Anil Kumar ◽  
S. Arjun ◽  
R.K. Gupta ◽  
P.V. Venkitakrishnan
Keyword(s):  
Heat Treatment ◽  
Aluminum Alloys ◽  
Industrial Applications ◽  
Age Hardening ◽  
Large Cross Section ◽  
Structural Applications ◽  
The Matrix ◽  
Peak Aged ◽  
Aged Temper ◽  
Short Time

Retrogression and re-aging (RRA) treatment was introduced to increase the stress corrosion cracking (SCC) resistance while retaining the strength attainable in T6 (peak aged) temper. Retrogression is a short-term heat treatment at an elevated temperature wherein a partial dissolution of metastable precipitates occurs, which are responsible for the hardening. During the next step, the material is re-aged in the regime of typical age hardening parameters to restore the strength with improved ductility. Response of RRA treatment has been reported on AA7XXX series Aluminum alloys such as AA7075, AA7050, AA7150, AA7049, and AA7010. Studies have been done on the effect of RRA on microstructure, mechanical properties such as tensile and hardness, corrosion, exfoliation corrosion, and SCC resistance by various researchers. The key characteristic of RRA is retrogression, which makes the re-precipitation in the matrix and coarsening of grain boundary precipitates such as MgZn2, η′. The retrogression treatment however requires high temperature and a short time, which limits the industrial application of RRA, especially in the heat treatment of the components with large cross section, due to the inherent thermal conductivity limitations. Hence, further work needs to be done in this area to apply this specialized heat treatment for industrial applications. This article brings out a comprehension of the changes in microstructure, tensile properties, and corrosion resistance of the various commonly used AA7XXX Aluminum alloys in structural applications with RRA heat treatment. The future scope of the work in RRA heat treatment is also discussed in this article.

The Characterization and Conservation of Aged Aluminum Alloys: Buckminster Fuller's Dymaxion House

2002 ◽  
Vol 712 ◽  
Author(s):  
Karen A. Trentelman ◽  
James Ashby ◽  
William T. Donlon
Keyword(s):  
Aluminum Alloys ◽  
Structural Integrity ◽  
Primary Aluminum ◽  
Grain Structure ◽  
Age Hardening ◽  
Original Structure ◽  
Visual Appearance ◽  
Henry Ford ◽  
Buckminster Fuller ◽  
Cladding Layers

ABSTRACTThe Dymaxion House is a unique historic dwelling structure designed by Buckminster Fuller. Built in the 1940s, the house was constructed of modern materials, most notably aluminum, which formed the walls, roof and many of the structural elements. The challenge faced in reconstructing the Dymaxion House at Henry Ford Museum & Greenfield Village was to preserve the original structure as much as possible while simultaneously accommodating the needs of exhibition (i.e. to restore the visual appearance and ensure sufficient structural integrity to allow the entrance of visitors). The primary aluminum alloys used in the house are equivalent to the modern alloy designations 2014 and 2024; both extruded forms and Alclad sheets were used. The alloy composition, age-hardening characteristics, cladding layers, grain structure and corrosion products of the aged aluminum components of the Dymaxion House have been studied. The results of these studies were used in consultation with conservators, engineers and corrosion scientists to determine the most appropriate course of treatment.

Three Strategies to Achieve Concurrent Strengthening by Ultrafine-Grained and Precipitation Hardenings for Severely Deformed Age-Hardnable Aluminum Alloys

2016 ◽  
Vol 1135 ◽  
pp. 161-166 ◽  
Author(s):  
Shoichi Hirosawa ◽  
Yong Peng Tang ◽  
Zenji Horita ◽  
Seung Won Lee ◽  
Kenji Matsuda ◽  
...  
Keyword(s):  
Aluminum Alloys ◽  
Volume Fraction ◽  
High Pressure Torsion ◽  
Equivalent Strain ◽  
Age Hardening ◽  
Cu Alloy ◽  
Ultrafine Grained ◽  
Δ Phase ◽  
Microalloying Elements ◽  
Wrought Aluminum Alloys

In this paper, comprehensive studies on the age-hardening behavior and precipitate microstructures of severely deformed and then artificially aged aluminum alloys have been conducted to clarify whether or not concurrent strengthening by ultrafine-grained and precipitation hardenings can be achieved. From our graphically-illustrated equivalent strain dependence of both the attained hardness and increment/decrement in hardness during aging (i.e. age-hardenability), three strategies to maximize the combined processing of severe plastic deformation and age-hardening technique are proposed. (1) Lowering of aging temperature and (2) utilization of microalloying elements can improve not only the attained hardness but also the age-hardenability of high-pressure torsion (HPT) specimens of Al-Mg-Si (-Cu) alloy due to the increased volume fraction of transgranular precipitates. A further increase in hardness can be achieved by (3) taking advantage of spinodal decomposition for HPTed Al-Li-Cu alloy, in which nanoscale precipitates of δ’ phase are successfully formed within ultrafine grains, irrespective of the higher number density of grain boundaries. The attained hardness of >HV290 in the latter alloy is almost the highest among conventional wrought aluminum alloys, and therefore our proposed strategies will be useful for designing concurrently strengthened severely-deformed age-hardenable aluminum alloys.

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