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Textured Mg alloy sheet samples were tensile tested parallel to the transverse direction, at Zener–Hollomon parameter values ranging from Z ~ 50 at room temperature and 10−3 s−1 down to Z ~ 18 at 350 °C and 10−5 s−1. At high Z, the samples exhibit strong texture evolution indicative of significant prismatic slip of dislocations with Burgers vectors. Correspondingly, the plastic anisotropy is high, r ~ 4. At low Z, the texture evolution is minimal and the response is nearly isotropic, r ~ 1. Previously, it has been asserted that the high ductility and low plastic anisotropy observed at low Z conditions is due to enhanced activity of non-basal slip modes, including prismatic slip of dislocations and pyramidal slip of and dislocations. The present results call this understanding into question and suggest that the enhanced ductility is more closely associated with the climb of dislocations.
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(2021) Accounting for the Effects of Dislocation Climb Mediated Flow in Mg Alloy ZK10 Sheet. In: Miller V.M., Maier P., Jordon J.B., Neelameggham N.R. (eds) . The Minerals, Metals & Materials Series. Springer, Cham. https://doi.org/10.1007/978-3-030-65528-0_6
Tensile samples of an Mg alloy ZK10 sheet were tested at a range of temperatures and strain rates designed to rather evenly probe a range of Zener Hollomon parameter values, from ln(Z) ≈ 15 (10–4 s−1 and 623 K) up to ln(Z) ≈ 50 (10–3 s−1 and 300 K). In contrast with more commonly examined Mg alloy AZ31B sheet material, ZK10 sheet material shows modest strain anisotropy (r-value) at low temperatures for both 45° (r45 ≈ 1.2) and TD (rTD ≈ 1.4) sample orientations, despite showing evidence of significant prismatic slip of dislocations, which often leads to high r-values at low temperatures. These low r-values become even lower (r45 ≈ 0.84 and rTD ≈ 0.89) at high temperatures. These behaviors are hypothesized to occur due to a distinct initial texture and deformation mechanism activity, which includes a modest level of tensile twinning and slip at both room and elevated temperature. A version of the viscoplastic self-consistent (VPSC) code, which accounts for the kinematics of dislocation climb, is used to simulate the behavior of a textured Mg alloy ZK10 sheet reveals that both the glide of pyramidal dislocations and the climb of basal < a > dislocations are required to describe the behavior at elevated temperatures.
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- Award ID(s):
- 1810197
- PAR ID:
- 10315293
- Editor(s):
- Miller, Victoria M.; Maier, Petra; Jordon, J. Brian; Neelameggham, Neel R.
- Date Published:
- Journal Name:
- Magnesium Technology 2021
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Conference Paper:
- https://doi.org/10.1007/978-3-030-65528-0_6
