Microstructure and Mechanical Behavior of Friction Stir Processed Ultrafine Grained Al-Mg-Sc Alloy
Twin-roll cast (TRC) Al-Mg-Sc alloy was frictionstir processed (FSP) to obtain ultrafine grained (UFG) microstructure. Average grain size of TRC alloy in as-received (AR) condition was 19.0 ± 27.2 μm. The grain size reduced to 0.73 ± 0.44 μm after FSP. About 80% of the grains were smaller than 1 μm in FSP condition. FSP resulted into 80% of the grain boundaries to have high angle grain boundary (HAGBs) character. Uniaxial tensile testing of UFG alloy showed an increase in yield strength (YS) and ultimate tensile strength (UTS) (by ∼100 MPa each) of the alloy with a very marginal decrease in total and uniform elongation (total - 27% in AR and 24% in UFG and uniform - 19% in AR and 14% in UFG). A theoretical model predicted that the grain refinement cannot take place via discontinuous dynamic recrystallization. Zener pinning model correctly predicted the grain size distribution for UFG alloy. From work hardening behaviors in both the conditions, it was concluded that grain boundary spacing is more important than the character of grain boundaries for influencing extent of uniform deformation of an alloy
N. Kumar et al., "Microstructure and Mechanical Behavior of Friction Stir Processed Ultrafine Grained Al-Mg-Sc Alloy," Materials Science and Engineering: A, Elsevier, Jul 2011.
The definitive version is available at http://dx.doi.org/10.1016/j.msea.2011.03.109
Mechanical and Aerospace Engineering
Materials Science and Engineering
Keywords and Phrases
EBSD; Friction Stir Processing; Grain Growth; Grain Refinement; Mechanical Characterization
Article - Journal
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