Thermally Activated Slip in Rare Earth Containing Mg-Mn-Ce Alloy, ME10, Compared with Traditional Mg-Al-Zn Alloy, AZ31

Published on Jun 1, 2019in JOM2.029
· DOI :10.1007/S11837-018-3310-5
Vikaas Bajikar1
Estimated H-index: 1
(UVA: University of Virginia),
Jishnu J. Bhattacharyya13
Estimated H-index: 13
(UVA: University of Virginia)
+ 1 AuthorsSean R. Agnew54
Estimated H-index: 54
(UVA: University of Virginia)
It is of interest to assess the thermally activated nature of the deformation mechanisms responsible for the anisotropic response of textured Mg alloys, especially in those alloys that do and do not contain rare earth elements. The repeated stress relaxation method in combination with elasto-viscoplastic self-consistent (EVPSC) polycrystal modeling is employed to determine the strain rate sensitivity and true activation volume of samples of textured, polycrystalline Mg alloys, ME10 and AZ31, loaded along different directions in both the hard-rolled (F) and annealed (O) tempers. The results of Haasen plot analyses suggest that a superposition of at least two key mechanisms is responsible for controlling the thermally activated motion of dislocation for both of the alloy types investigated. One has a lower activation volume (solute-dislocation interaction and/or cross-slip), while the other is the ever-present forest dislocation interaction.
#1Jishnu J. Bhattacharyya (UVA: University of Virginia)H-Index: 13
#2Sean R. Agnew (UVA: University of Virginia)H-Index: 54
Last. H. El Kadiri (MSU: Mississippi State University)H-Index: 19
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Al alloy 7085 in the T711 temper has been proposed as a lightweight metallic armor material. The room temperature constitutive response is assessed by compression testing at quasi-static (0.001 s−1) and dynamic (1000 s−1) strain rates along the rolling (RD), transverse (TD), and normal (ND) directions. The flow strength, plastic strain anisotropy (r-values) and texture evolution is measured along each direction. While the flow stress exhibits only mild anisotropy, the compressive r-values reveal...
16 CitationsSource
#1Jishnu J. Bhattacharyya (UVA: University of Virginia)H-Index: 13
#2Fulin Wang (UVA: University of Virginia)H-Index: 10
Last. Sean R. Agnew (UVA: University of Virginia)H-Index: 54
view all 6 authors...
Abstract The mechanical response of rare earth containing Mg alloy, WE43, plates is found to be more isotropic, as compared to conventional alloys like AZ31, despite a moderately strong texture. In order to understand the grain-level deformation mechanisms which are responsible, the elastoplastic self-consistent (EPSC) polycrystal plasticity code, including the recently developed twinning–detwinning (TDT) model, is used to describe the homogeneous plastic flow of WE43-T5, plate at quasistatic an...
71 CitationsSource
#1Zuzanka Trojanová (Charles University in Prague)H-Index: 21
#2Kristián Máthis (Charles University in Prague)H-Index: 19
Last. František Chmelík (Charles University in Prague)H-Index: 27
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Abstract Magnesium alloy AZ63 was deformed at temperatures between room temperature and 300 °C. Stress relaxation tests were performed in order to reveal the physical base of the deformation process/-es. Internal and effective components of the applied stress have been estimated. Very high values of the internal stress estimated at room temperature decrease rapidly with increasing deformation temperature. The apparent activation volume decreases with increasing effective stress. Estimated values...
24 CitationsSource
#1Pavel Lukáč (Charles University in Prague)H-Index: 29
#2Zuzanka Trojanová (Charles University in Prague)H-Index: 21
Stress relaxation tests have been used in order to determine parameters of a possible thermally activated process in AZ31 magnesium alloy. The samples were deformed at a constant initial strain rate of 6.7x10-5 s-1 at various temperatures between room temperature and 300 °C. Stress relaxation, i.e. a decrease in the stress with time, was measured at various stress levels and at various temperatures. An analysis of the stress relaxation curves enabled to estimate the internal stress as a function...
3 CitationsSource
The Haasen plot (inverse activation area 1/Delta alpha vs. offset flow stress sigma-sigma(s)) for solute-strengthened alloys is usually assumed additive, 1/Delta alpha = 1/Delta alpha(s) + 1/Delta alpha(f), with 1/Delta alpha(f) similar to beta(sigma-sigma(s)) due to forest interactions. Experiments often show a slope textlessbeta. Here, a model for the dislocation activation enthalpy is proposed that predicts a slope 1/(Delta alpha(s)sigma(s)) determined only by solute parameters Delta alpha(s)...
16 CitationsSource
#1Huamiao Wang (McMaster University)H-Index: 24
#2B. Raeisinia (UVA: University of Virginia)H-Index: 13
Last. Carlos N. Tomé (LANL: Los Alamos National Laboratory)H-Index: 80
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Various self-consistent polycrystal plasticity models for hexagonal close packed (HCP) polycrystals are evaluated by studying the deformation behavior of magnesium alloy AZ31B sheet under different uniaxial strain paths. In all employed polycrystal plasticity models both slip and twinning contribute to plastic deformation. The material parameters for the various models are fitted to experimental uniaxial tension and compression along the rolling direction (RD) and then used to predict uniaxial t...
217 CitationsSource
#1Huamiao Wang (McMaster University)H-Index: 24
#2Peidong Wu (McMaster University)H-Index: 51
Last. Yonggang Huang (NU: Northwestern University)H-Index: 141
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Abstract A large strain elastic–viscoplastic self-consistent (EVPSC) model for polycrystalline materials is developed. At single crystal level, both the rate sensitive slip and twinning are included as the plastic deformation mechanisms, while elastic anisotropy is accounted for in the elastic moduli. The transition from single crystal plasticity to polycrystal plasticity is based on a completely self-consistent approach. It is shown that the differences in the predicted stress–strain curves and...
210 CitationsSource
#1A. Jain (UVA: University of Virginia)H-Index: 8
#2Ozgur Duygulu (UVA: University of Virginia)H-Index: 13
Last. Sean R. Agnew (UVA: University of Virginia)H-Index: 54
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Abstract The grain size dependence of the tensile properties and the deformation mechanisms responsible for those properties are examined for Mg alloy, AZ31B, sheet. Specifically, the Hall–Petch effect and strain anisotropy ( r -value) are characterized experimentally, and interpreted using polycrystal plasticity modeling. {1 0 . 2} extension twins, {1 0 . 1} contraction twins, and so-called “double-twins” are observed via microscopy and diffraction-based techniques, and the amount of twinning i...
283 CitationsSource
#1Tomáš KrumlH-Index: 22
#2O. CoddetH-Index: 5
Last. Jean-Luc Martin (École Polytechnique)H-Index: 18
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The determination of the thermal and athermal stress components using relaxation experiments along a stress-strain curve is critically evaluated. Short-term stress-relaxations are performed along the stress-strain curve of single crystals of Ge at 850 K, Cu, and Ni3Al at 300 K. They are analyzed by three different equations with two or three parameters including the athermal stress. The stress components obtained are compared to the values determined by stress-reduction experiments considered as...
26 CitationsSource
Uniaxial compression test data were obtained from magnesium alloy AZ31B sheet material tested along three sample directions (rolling, transverse and normal direction) over the temperature range T = 22–250 ◦ C. The yield point during in-plane compression is insensitive to temperature, up to 200 ◦ C, suggesting that athermal mechanisms are responsible for yielding. The in-plane compression samples exhibit very low r-values, which provides another signature of significant twinning activity in magne...
395 CitationsSource
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Last. Sean R. AgnewH-Index: 54
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