Mechanism of the Bauschinger effect in Al-Ge-Si Alloys
SCIE
SCOPUS
- Title
- Mechanism of the Bauschinger effect in Al-Ge-Si Alloys
- Authors
- Gan, W; Bong, H.J; Lim, H; Boger, R; BARLAT, FREDERIC GERARD; Wagoner, R.H
- Date Issued
- 2017-01
- Publisher
- ELSEVIER SCIENCE SA
- Abstract
- Wrought Al-Ge-Si alloys were designed and produced to ensure dislocation bypass strengthening ("hard pin" precipitates) without significant precipitate cutting/shearing ("soft pin" precipitates). These unusual alloys were processed from the melt, solution heat treated and aged. Aging curves at temperatures of 120, 160, 200 and 240 degrees C were established and the corresponding precipitate spacings, sizes, and morphologies were measured using TEM. The role of non-shearable precipitates in determining the magnitude of Bauschinger was revealed using large-strain compression/tension tests. The effect of precipitates on the Bauschinger response was stronger than that of grain boundaries, even for these dilute alloys. The Bauschinger effect increases dramatically from the under-aged to the peak aged condition and remains constant or decreases slowly through over-aging. This is consistent with reported behavior for Al-Cu alloys (maximum effect at peak aging) and for other Al alloys (increasing through over-aging) such as Al-Cu-Li, Al 6111, Al 2524, and Al 6013. The Al-Ge-Si alloy response was simulated with three microstructural models, including a novel SD (SuperDislocation) model, to reveal the origins of the Bauschinger effect in dilute precipitation-hardened / bypass alloys. The dominant mechanism is related to the elastic interaction of polarized dislocation arrays (generalized pile-up or bow-out model) at precipitate obstacles. Such effects are ignored in continuum and crystal plasticity models.
- Keywords
- WORK-HARDENING BEHAVIOR; PLANE-STRAIN DEFORMATION; ALUMINUM SINGLE-CRYSTALS; IF STEEL; PLASTIC ANISOTROPY; INTERNAL-STRESSES; AL-(SI,GE) ALLOYS; HARDENING/SOFTENING BEHAVIOR; DISLOCATION DENSITIES; METALLIC MATERIALS
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/41295
- DOI
- 10.1016/j.msea.2016.12.020
- ISSN
- 0921-5093
- Article Type
- Article
- Citation
- MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, vol. 684, page. 353 - 372, 2017-01
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