Abstract
This study investigated a mechanism of reducing solidification cracking susceptibility by grain refinement. Previously, the occurrence of grain boundary sliding (GBS) is implied as one mechanism, which is known for the characteristics of superplastic deformation.To verify GBS occurrence during solidification of an Al-5 wt%Mg alloy, the effects of refinement on the true stress-true strain curve and the effective power-law coefficient neff (the reciprocal of the strain rate sensitivity) were investigated in a partially solidified state. Furthermore, the contribution of GBS to deformation was examined using the index ξGBS defined in the research field of superplasticity. The results are following.(1) The grain refined structure elongation is greater than that in the coarse grain structure regardless of the solid fraction. Greater elongation is expected to result from both lower value of the coefficient neff and the higher contribution of the GBS, which provide more uniform deformation.(2) Maximum elongation of up to 20% was found at 480 °C (fs: 0.939) in the grain refined structure. Based on the knowledge of superplastic behavior, the values of both neff≈2 and ξGBS≈70% at the temperature indicates superplastic-like deformation during the solidification, reducing solidification cracking susceptibility by grain refinement.
| Original language | English |
|---|---|
| Pages (from-to) | 417-425 |
| Number of pages | 9 |
| Journal | Materials Science and Engineering A |
| Volume | 667 |
| DOIs | |
| Publication status | Published - 2016 Jun 14 |
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Keywords
- Al-Mg alloy
- Grain refinement
- Hot tearing
- Semi-solid state
- The strain rate sensitivity
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics
- Mechanical Engineering
- Mechanics of Materials
Cite this
Grain refinement effects on the strain rate sensitivity and grain boundary sliding in partially solidified Al-5 wt%Mg alloy. / Takai, R.; Kimura, S.; Kashiuchi, R.; Kotaki, H.; Yoshida, Makoto.
In: Materials Science and Engineering A, Vol. 667, 14.06.2016, p. 417-425.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Grain refinement effects on the strain rate sensitivity and grain boundary sliding in partially solidified Al-5 wt%Mg alloy
AU - Takai, R.
AU - Kimura, S.
AU - Kashiuchi, R.
AU - Kotaki, H.
AU - Yoshida, Makoto
PY - 2016/6/14
Y1 - 2016/6/14
N2 - This study investigated a mechanism of reducing solidification cracking susceptibility by grain refinement. Previously, the occurrence of grain boundary sliding (GBS) is implied as one mechanism, which is known for the characteristics of superplastic deformation.To verify GBS occurrence during solidification of an Al-5 wt%Mg alloy, the effects of refinement on the true stress-true strain curve and the effective power-law coefficient neff (the reciprocal of the strain rate sensitivity) were investigated in a partially solidified state. Furthermore, the contribution of GBS to deformation was examined using the index ξGBS defined in the research field of superplasticity. The results are following.(1) The grain refined structure elongation is greater than that in the coarse grain structure regardless of the solid fraction. Greater elongation is expected to result from both lower value of the coefficient neff and the higher contribution of the GBS, which provide more uniform deformation.(2) Maximum elongation of up to 20% was found at 480 °C (fs: 0.939) in the grain refined structure. Based on the knowledge of superplastic behavior, the values of both neff≈2 and ξGBS≈70% at the temperature indicates superplastic-like deformation during the solidification, reducing solidification cracking susceptibility by grain refinement.
AB - This study investigated a mechanism of reducing solidification cracking susceptibility by grain refinement. Previously, the occurrence of grain boundary sliding (GBS) is implied as one mechanism, which is known for the characteristics of superplastic deformation.To verify GBS occurrence during solidification of an Al-5 wt%Mg alloy, the effects of refinement on the true stress-true strain curve and the effective power-law coefficient neff (the reciprocal of the strain rate sensitivity) were investigated in a partially solidified state. Furthermore, the contribution of GBS to deformation was examined using the index ξGBS defined in the research field of superplasticity. The results are following.(1) The grain refined structure elongation is greater than that in the coarse grain structure regardless of the solid fraction. Greater elongation is expected to result from both lower value of the coefficient neff and the higher contribution of the GBS, which provide more uniform deformation.(2) Maximum elongation of up to 20% was found at 480 °C (fs: 0.939) in the grain refined structure. Based on the knowledge of superplastic behavior, the values of both neff≈2 and ξGBS≈70% at the temperature indicates superplastic-like deformation during the solidification, reducing solidification cracking susceptibility by grain refinement.
KW - Al-Mg alloy
KW - Grain refinement
KW - Hot tearing
KW - Semi-solid state
KW - The strain rate sensitivity
UR - http://www.scopus.com/inward/record.url?scp=84969256702&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84969256702&partnerID=8YFLogxK
U2 - 10.1016/j.msea.2016.05.023
DO - 10.1016/j.msea.2016.05.023
M3 - Article
VL - 667
SP - 417
EP - 425
JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
SN - 0921-5093
ER -