Grain Boundary Contributions Research Articles

Effect of intercalated anions on the electrical and dielectric properties of NiAl-X layered double hydroxide ($$\text {X}\, =\, \text {CO}_{3}^{2-}$$, $$\text {NO}_{3}^{-}$$ and $$\text {H}_{2}\text {PO}_{4}^{-})$$: investigation by impedance spectroscopy

This paper reports the effect of interlayer species on the electrical and dielectric behaviours of a lamellar structure. The successful intercalation of three oxyanions ( $$\text {CO}_{3}^{2-}$$ , $$\text {NO}_{3}^{-}$$ and $$\text {H}_{2}\text {PO}_{4}^{-})$$ in the interlayer space of NiAl-layered double hydroxide (LDH) was confirmed by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis and inductively coupled plasma. Using complex impedance spectroscopy measurements, equivalent circuit consisting of three serially connected R-CPE units was established for each sample. Each unit contains a resistance and a constant phase element representing contributions of grain, grain boundary and electrode interface, which allowed the determination of their electrical parameters. The adjustment of experimental data of conductivity by the double power law allowed the determination of $$\sigma _{\mathrm {dc}}$$ and other conductivity parameters, and therefore, the investigation of the effect of intercalated anions on NiAl LDH electrical behaviour. Indeed, dihydrogenophosphates intercalated sample was found to decrease $$\sigma _{\mathrm {ac}}$$ over the frequency range of measure, comparing to the other anions. The intercalation of this anion has also an effect on dielectric properties, it reduces the value of dielectric constant of NiAl LDH, and shifts the maximum of tan $$\delta $$ towards medium frequencies with a decrease in the value of loss tangent above $$10^{5}$$ Hz. Carbonate and nitrate intercalated LDH showed a similarity in their effect on electrical and dielectric properties of NiAl LDH.

Elucidating the dual role of grain boundaries as dislocation sources and obstacles and its impact on toughness and brittle-to-ductile transition

In this paper, we resolve the role of grain boundaries on toughness and the brittle-to-ductile transition. On the one hand, grain boundaries are obstacles for dislocation glide. On the other hand, the intersection points of grain boundaries with the crack front are assumed to be preferred dislocation nucleation sites. Here, we will show that the single contributions of grain boundaries (obstacles vs. source) on toughness and the brittle-to-ductile transition are contradicting, and we will weight the single contributions by performing carefully designed numerical experiments by means of two-dimensional discrete dislocation dynamics modelling. In our parameter studies, we vary the following parameters: (i) the mean free path for dislocation glide, δ, combined with (ii) the (obstacle) force of the grain boundary, ϕ, and (iii) the dislocation source spacing along the crack front, λ. Our results show that for materials or microstructures for which the mean distance of the intersection points of grain boundaries with the crack front is the relevant measure for λ, a decrease of grain size results in an increase of toughness. The positive impact of grain boundaries outweighs the negative consequences of dislocation blocking. Furthermore, our results explain the evolving anisotropy of toughness in cold-worked metals and give further insight into the question of why the grain-size-dependent fracture toughness passes through a minimum (and the brittle-to-ductile transition temperature passes through a maximum) at an intermediate grain size. Finally, a relation of the grain-size-dependence of fracture toughness in the form of K(dδ, dλ) = KIC + kdδ0.5/dλ is deduced.

Synthesis and characterization of Ruddlesden-Popper system (Ba1−xSrx)2SnO4

The samples of (Ba1−xSrx)2SnO4 with x = 0, 0.10, 0.20, 0.40, 0.80, 1.00 were synthesized by a high-temperature solid state ceramic route. Lattice parameters obtained from the Rietveld profile analysis; decreased with increasing Sr. The decreasing nature of lattice parameters indicated the complete solubility of Sr at Ba-site. Further, incorporation of Sr at Ba-site has been studied by Fourier transform infrared (FTIR) spectroscopy. The dielectric constant and dissipation factor increases with increasing Sr. Contribution of grain and grain boundary were resolved by complex modulus spectroscopy analysis. AC conductivity spectra of the entire sample follow Universal Jonscher's power law. The similar value of activation energy obtained from relaxation frequency and dc conductivity implies that the origin of conduction and relaxation mechanisms remains the same throughout the samples. The modulus and conductivity spectra of solid solutions nicely follow the time-temperature superposition (TTSP) principle. Further, conductivity spectra of solid solutions were studied by Ghosh and Summerfield scaling.

Hot Workability Characteristics and Optimization of Processing Parameters of 7475 Aluminum Alloy Using 3D Processing Map

Hot compression testing was used to investigate the hot deformation behavior of 7475 aluminum alloy in a temperature range of 573-723 K and a strain rate range of 0.01-10 s−1. The hot workability was studied by means of constitutive analysis, three-dimensional processing maps, and microstructure characterizations using optical microscopy, electron back-scattered diffraction, and transmission electron microscopy. The results showed that the flow stress was increased with the increment of strain rates or the decrement of deformation temperature. Based on 3D processing, a temperature range of 623-673 K and a strain rate range of 0.01-0.1 s−1 were proposed to domain the process. Dynamic softening mechanisms were found to be associated with different contributions of dynamic recovery, dynamic recrystallization, and grain boundary sliding in various deformation conditions. These findings, along with the microstructure observation, suggested that the safe-deformation regimes with higher dissipation efficiency could be attributed to the continuous dynamic recrystallization and grain boundary sliding. The flow-instability regimes could be caused by the flow localizations and the adiabatic shear bands.

Dielectric Relaxation Processes in Mn2O3/Reduced Graphene Oxide Nanocomposites

One essential for developing electronic materials for device applications is an understanding of the materials’ dynamic relaxation processes. This paper seeks to improve our understanding of the relaxation processes in pure Mn2O3 and Mn2O3/reduced graphene oxide (RGO) nanocomposites on the basis of the capacitive contributions of grain and grain boundaries (GBs). To achieve this, the dielectric properties for pure Mn2O3 and Mn2O3/xRGO (x = 5, 10 and 20 wt.%) nanocomposites, prepared theby sol–gel method, were investigated over a wide frequency range at room temperature using a broadband dielectric spectrometer (BDS). Crystalline structure, molecular structure and microstructure of samples were characterized by x-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscope, respectively. XRD analysis showed the formation of orthorhombic crystalline structure in all samples with no considerable changes in the crystalline structure. FTIR spectra did not show new absorption bands upon introducing the graphene content. Characteristic peaks corresponding to Mn-O vibration were found to have shifted to lower wavenumbers, indicating an increase of particle size. The dielectric study showed some changes in the dielectric properties of the Mn2O3/RGO nanocomposites. For pure Mn2O3, two relaxation processes were clearly observed; the slower one positioned at high relaxation time (τ = 1.7 × 10−2 s) is associated to the GBs capacitive contribution, while the faster one of lower τ (= 2.5 × 10−5 s) is associated to the grain capacitive contribution. For Mn2O3/RGO nanocomposites, τ for both process slightly increased with increasing RGO up to 10 wt.% then remarkably decreased to much lower values at 20 wt.%. Interestingly, BDS, rather than XRD and FTIR techniques, is considered as a powerful and sensitive technique, even for small changes in Mn2O3/RGO nanocomposites.

Revealing the effect of grain boundary segregation on Li ion transport in polycrystalline anti-perovskite Li3ClO: a phase field study

Lithium ion transport in a polycrystalline solid-state electrolyte (SSE) is directly linked to the properties of lithium ion batteries. Grain boundaries (GBs), as essential defects in SSE, have been found to play a significant role in the overall kinetics of lithium ion transport, however, the mechanism is not well understood due to the complex role of GBs. The GBs could affect the overall kinetics of ionic transport in the SSEs in two ways: (i) Li/Na diffusivities inside the GBs could be different from those in the bulk, and (ii) point defect segregation at the GBs. The first aspect is well recognized, whereas the second one has been rarely studied. In this study, a combination of first principles and phase field calculations were performed, in which the interaction between point defects and grain boundaries were considered at different scales, to reveal the role of GBs in the overall ionic conduction of SSE anti-perovskite Li3ClO. The results show that defect segregation, which varies significantly with the GB orientation, reinforces the negative contribution of GBs on the overall ionic diffusivity by approximately one-order of magnitude. This study could help improve the fundamental understanding of ionic transport in polycrystalline SSEs, and provide guidance for the design of new SSEs with excellent ionic conductivity.

Annealing-temperature dependence of the electrical properties of Ba0.8Pb0.2TiO3 as a PTC material

In this research, we investigate how the annealing temperature affects the electrical properties of Ba0.8Pb0.2TiO3 as a positive temperature coefficient material. The material was synthesized via solid-state sintering. The grain size was varied by varying the annealing temperature between 850 °C and 1000 °C for 4 h. Characterization via X-ray diffraction showed that a single-phase compound was formed exhibiting a tetragonal phase. The microstructure was observed using scanning electron microscopy. Average grain size was observed to be between 5 and 10μm. The electrical properties as characterized using impedance spectroscopy showed the presence of grain and grain-boundary contributions in the annealed samples. Dielectric constant and dielectric relaxation phenomenon as a function of annealing temperature have been studied.

Studies on Magnetic and Dielectric Properties of Antiferromagnetically Coupled Dinuclear Cu(II) in a One-Dimensional Cu(II) Coordination Polymer.

A one-dimensional Cu(II) coordination polymer with encapsulated antiferromagnetically coupled binuclear Cu(II) has been synthesized by using 5-nitroisophthalic acid (5-N-IPA) and 4-aminopyridine (4-APY) [Cu2(5-N-IPA)2(4-APY)4]n (1). Electrical properties are examined by complex impedance (Z*), dielectric permittivity (ε*), and ac conductivity studies at different frequencies (10 kHz–5 MHz) and temperatures (253–333 K). The contribution of grain and grain boundary has been explained by a different theoretical model. The variable temperature magnetic susceptibility data for compound 1 were recorded between 300 and 2 K. The shape of the curve (χMT vs T) indicates dominant antiferromagnetic coupling, which results from the interaction between the copper(II) atoms.

Structural and electrical characteristics of Bi2YZrVO9 ceramic

A new bismuth based layered structure compound, Bi2YZrVO9, synthesized by the mixed oxide reaction method, is found to crystallize in the orthorhombic crystal system. The characteristic Nyquist plots suggest the contribution of only grains to the electrical properties up to 400 °C and both grains and grain boundaries at higher temperatures. Based on impedance spectroscopy data and complex permittivity plot, the Cole-Cole model was used to analyze the contributions of grains and grain boundaries to the resistive and capacitive properties of the material. Analysis of electrical conductivity, using Jonscher’s power law, suggests the correlated barrier hopping being the dominant conduction mechanism in the compound. The activation energy for the conduction process in the range of 0.97 eV–0.75 eV corresponding to the frequency range 1 kHz–1 MHz suggest the role of oxygen vacancies in the conduction process.

High-Temperature Dielectric Relaxation Behaviors in Mn3O4 Polycrystals.

High temperature dielectric relaxation behaviors of single phase Mn3O4 polycrystalline ceramics prepared by spark plasma sintering technology have been studied. Two dielectric relaxations were observed in the temperature range of 200 K–330 K and in the frequency range of 20 Hz–10 MHz. The lower temperature relaxation is a type of thermally activated relaxation process, which mainly results from the hopping of oxygen vacancies based on the activation energy analysis. There is another abnormal dielectric phenomenon that is different from the conventional thermally activated behavior and is related to a positive temperature coefficient of resistance (PTCR) effect in the temperature region. In line with the impedance analyses, we distinguished the contributions of grains and grain boundaries. A comparison of the frequency-dependent spectra of the imaginary impedance with imaginary electric modulus suggests that both the long range conduction and the localized conduction are responsible for the dielectric relaxations in the Mn3O4 polycrystalline samples.

Effect of Cu substitution on structural and electric transport properties of Ni-Cd nanoferrites

Nanocrystalline samples of Ni0.7−xCuxCd0.3Fe2O4 (x = 0.0–0.5, with step of 0.1) have been synthesized via auto-combusted sol-gel method. In this study, we present the structural and electric properties of Cu substituted Ni-Cd ferrite nanoparticles at room temperature with varying frequencies from 20 Hz to 15 MHz. X-ray diffraction (XRD) patterns of samples confirm the single-phase cubic spinel structure without impurity. The crystallite size of samples is found in the nano-scale range (17–27 nm) and the lattice parameter is found to increase linearly with Cu content. The surface morphology of samples is studied through a Field Emission Scanning Electron Microscopy (FESEM) and the presence of elements in the samples are confirmed by Energy Dispersive X-ray (EDX) techniques. The materials show dielectric dispersion up to 10 kHz frequencies and their loss tangent values remain very low at MHz frequencies. The impedance and modulus spectroscopy confirm the existence of non-Debye relaxation phenomena of the materials and resolve the contribution of grain and grain boundary. The ac conductivity shows normal behavior with frequency, which is explained on the basis of hopping mechanism.

Grain size and temperature effect on the tensile behavior and deformation mechanisms of non-equiatomic Fe41Mn25Ni24Co8Cr2 high entropy alloy

The effect of the grain size on the tensile properties and deformation mechanisms of a nonequiatomic Fe41Mn25Ni24Co8Cr2 high-entropy alloy was studied in the temperature range between 298 and 1173 K by preparing the samples with three different grain sizes through severe plastic deformation and subsequent annealing: ultrafine (sub)grain size (≤0.5 μm), 8.1 μm and 590.2 μm. In the temperature between 298 and 773 K, the material with the large grain size of 590.2 μm exhibited the largest tensile ductility (57 %–82 %) due to its high strain hardening associated with mechanical twinning, but it exhibited the lowest strength due to its large grain size. The material with the ultrafine (sub)grain size exhibited the lowest tensile ductility (3 %–7 %) due to a greatly reduced strain hardening ability after severe plastic deformation, but it exhibited the highest strength due to the dislocation strengthening and grain refinement strengthening. At tensile testing at temperatures above 973 K, recrystallization occurred in the material with the ultrafine (sub)grains during the sample heating and holding stage, leading to the formation of fine and equiaxed grains with the sizes of 6.8-13.5 μm. The deformation behavior of the Fe41Mn25Ni24Co8Cr2 with different grain sizes in the high temperature range between 973 and 1173 K, where pseudosteady-state flow was attained in the stress-strain curves, could be explained by considering the simultaneous contribution of grain boundary sliding and dislocation-climb creep to total plastic flow. The activation energies for plastic flow for the materials with different grain sizes were similar as ∼199 kJ/mol. In predicting the deformation mechanism, it was important to consider the change in grain size by rapid grain growth or recrystallization during the sample heating and holding stage because grain boundary sliding is a grain-size-dependent deformation mechanism. The sample with the ultrafine (sub)grains exhibited the large tensile elongations of 30 %–85 % due to its high strain rate sensitivity, m (0.1-0.5) at temperatures of 973–1173 K. The material with the large grain size of 590.2 μm exhibited the very small elongations of 0.2 %–8 % due to its small m values (0.1-0.2) and occurrence of brittle intergranular fracture at the early stage of plastic deformation.

Microstructure and mechanical properties of a high-Zn aluminum alloy prepared by melt spinning and extrusion

High-Zn aluminum casting alloys usually contain coarse dendrites, network eutectoid structure and casting defects which deteriorate the mechanical properties seriously. In order to overcome these problems, the combination of melt spinning and extrusion was explored for microstructure modification in this work. A high-Zn aluminum alloy (Al–27Zn-1.5Mg-1.2Cu-0.08Zr) was prepared by melt spinning and extrusion. The results show that the melt spun alloy mainly consists of micro-sized network-like grain boundary (GB) η-MgZn2 structure (η phase) and disc-like precipitates (GP-zone, η′-phase and η-precursor) embedded into fine α-Al grains with high solute atomic concentration. After extrusion, the grain size of α-Al is further refined due to the recrystallization, and primary network GB η-phase structures are transformed to granular η particles. Moreover, the extrusion induces the precipitation of nano-sized η′-phase, η-precursor and Zn phases. As a result, the alloy exhibits a high tensile strength of 485 MPa and a reasonable elongation of 5.2%. The contributions of grain boundary, dislocation, solid solution and precipitate strengthening to the yield strength are calculated according to the microstructure analysis, and it is found that precipitation strengthening is the main strengthening mechanism in this alloy. Fracture analysis shows that micro-cracks preferentially occur at α-Al/η phase interfaces due to interfacial de-cohesion, and propagate along the GBs.

Structural elucidation and dielectric behavior evaluation of sol-gel synthesized Co–Al co-substituted M-type hexaferrite materials

In this study, the sol-gel method was employed for the preparation of M-type hexaferrites Sr1-xAlxFe12-yCoyO19. Annealing of these samples was done at 1200 °C for 4 h. The single phase structure of all the prepared samples of M-type hexaferrites was observed by the X-ray diffraction (XRD) plots. The changes were examined in lattice parameters (a and c), cell volume, as well as in c/a ratio. The variations in c/a ratio were attributed to the changes in lattice parameters. The volume of the cell was found within the range 676.822–667.036 Å3. Debye Scherrer's formula was used for the measurement of crystallite size, which was found in the range of 26.026 to 22.634 nm. The variations were also perceived in bulk density (δb) and porosity (%) with the incorporation of Al–Co concentration. There was reduction in X-ray density (δx), due to the increment in substitution concentration. Fourier transform infrared spectroscopy (FTIR) was performed in the range 400–3000 cm−1, which displayed specific absorption bands regarding hexagonal ferrites. Dielectric parameters including dielectric constant, dielectric loss, tan loss, and AC-conductivity revealed decreasing behavior, due to Al–Co substitution. The slope “n” was measured from graph of log(σac) as a function of log(ω), and found within the range 0.697–0.972. The grain boundary contribution of all the synthesized samples was evidenced via Cole-Cole plots, and extraordinary contribution of grain boundaries in conduction phenomenon was established by the presence of only one semi-circle in Cole-Cole plots. Therefore, the smaller dielectric parameters of the investigated M-type hexaferrites recommended their feasible role in large frequency applications (e.g., dielectric resonators, microwave absorbers, phase shifters, and stealth technology).

Structure and ferroelectric properties of lead nickel tungsten titanate: Pb(Ni1/3 Ti1/3 W1/3) O3 single perovskite

Lead nickel tungsten titanate Pb(Ni1/3 Ti1/3 W1/3) O3 single perovskite ceramics were prepared by using a high temperature solid-state reaction technique. The structural analysis of the sample confirms tetragonal crystal structure with space group P4mm having average crystallite size 73 nm, which is well supported from FTIR observations. The dielectric spectra with function of frequency and temperature suggest that sample is semiconducting in nature following NTCR behavior. The complex impedance results showed the contribution of grain and grain boundaries in the conduction mechanism. The activation energies were determined from the ac conductivity data in the temperature range of 200–350 °C and 360–500 °C. It has been observed that with the rise of frequency and temperature, the activation energy increases in the sample. The greater value of activation energy always supports the conduction mechanism due to hopping of the charge carriers. The semicircular arcs of Cole-Cole plots confirm that the sample is semiconducting in nature which supports our dielectric results.

Dielectric, ferroelectric, piezoelectric properties, and impedance spectroscopy of (Ba0.85Ca0.15)(Ti0.9 Zr0.1)O3-x% (K0.5Bi0.5)TiO3 lead-free ceramics

The influence of (K0.5Bi0.5)TiO3 on structure, microstructure and piezoelectric properties of (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 (BCTZ) piezoelectric ceramics was investigated. Impedance spectroscopy was used to get better understanding of the electrical properties of the materials as a function of temperature and frequency. The XRD results indicate the presence of the morphotropic phase in the BCTZ–xKBT system. Dielectric and complex impedance spectroscopic studies were carried out over wide frequency (i.e. 102–106 Hz) and temperature (30–500 °C) ranges. The diffuseness of the dielectric peak was found to increase with increasing KBT proportion. The nature of frequency dependence of AC conductivity of BCTZ-KBT follows the Jonscher power law and calculated DC conductivity follows Arrhenius behavior. The Nyquist plots suggest the contribution of grains and grain boundaries to the electrical behavior of the materials. The ceramic with x = 0.25 mol% KBT demonstrates good properties: d33 = 226 PC/N, Tc = 110 °C, kp = 27.85%, εr =10,566, tanδ = 2.3%.

Barium deficiency and sintering temperature effects on structural and transport properties of La0.5Eu0.2Ba0.3−x□xMnO3 manganites

La0.5Eu0.2Ba0.3−x□xMnO3 (x = 0.00, 0.05 and 0.15) samples were prepared using sol–gel method and annealed at Ts = 750 and 950 °C. The X-ray diffraction technique shows that all samples crystallize in the rhombohedral structure with R-3c space group. Electrical properties of the prepared compounds were investigated using impedance spectroscopy technique in a wide temperature range (80–440 K). The results show a semiconductor behavior for all samples. From dc-conductivity (σdc) analysis, it is observed that increasing barium-deficiency content and sintering temperature improves the electrical conductivity. It is also found that the conduction mechanism is governed by hopping process. Ba-deficiency and sintering temperature affects the activation energy (Ea). From σdc, in the temperature range of 250–480 K and at Ts = 750 °C, it is found that Ea1 decreases from 190 meV for x = 0.00 to 164 meV for x = 0.15. Also, for x = 0.00, Ea1 decreases from 165 meV at Ts = 750 °C to 145 meV at Ts = 950 °C. Complex impedance analysis indicates the presence of non-Debye type relaxation. Such analysis confirms the contribution of grain boundary on the conduction. The activation energy Ea2 deduced from dc-conductivity matches very well with the value estimated from relaxation time (Eaτ) indicating that relaxation and transport mechanisms are related to the same defect.

Structural, AC conductivity, conduction mechanism and dielectric properties of La0.62Eu0.05Ba0.33Mn0.85Fe0.15O3 ceramic compound

The new perovskite compound La0.62Eu0.05Ba0.33Mn0.85Fe0.15O3 was successfully synthesized via the sol–gel process. X-ray diffraction revealed that our sample is pure and crystallizes in the orthorhombic structure with Pbnm space group. Electrical properties were performed using the complex impedance spectroscopy technique in the range of frequency (40–10 MHz) and at various temperatures (80–400 K). AC-conductivity results are well described by the universal Jonsher’s power law at low temperatures and the DC-conductivity data are well fitted by the small polaron hopping model at high temperatures. Impedance results show a negative temperature coefficient of resistance (NTCR) which discloses the semiconductor behaviour of the studied sample. Nyquist plots were well fitted by an equivalent circuit involving the contribution of grain and grain boundaries in the conduction process. Giant dielectric values, useful in electronic devices, were obtained. Moreover, a relaxation diffuse phase transition is attributed to a strong heterogeneity in A and B sites of the studied perovskite.

Influence of dislocations and grain boundaries on diffraction line profiles of nano-crystalline materials: A numerical study

In the present paper, the contributions of dislocations and grain boundaries to the broadening of diffraction line profile have been delineated. Contribution of each factor is studied on single as well as poly crystalline ‘virtual samples’ containing different dislocation configurations generated by molecular dynamics and evaluating the simulated X-ray diffraction line profiles of these samples. Individual contributions to diffraction line profiles by different sample features, such as domain size, dislocations, grain boundaries, have been isolated by deconvoluting the evaluated diffraction line profiles. The diffraction line profiles exhibited significant asymmetry and peak splitting in the case of dislocations with predominantly edge character. It has been shown that splitting of diffraction peaks carries information about the magnitude of Burger’s vectors of the dislocations. Application of the variance method based on single peak fitting and Wilkens method based on whole powder pattern fitting of line profile analysis on the computed diffraction line profiles, showed that while accurate domain size estimation was possible, there was an under estimation of dislocation density at the high dislocation density and small grain size regime considered in the present study.

Deformation behavior at room temperature ranges of fine-grained Mg–Mn system alloys

Tensile properties and deformation behavior were investigated on Mg dilute binary alloys (Mg-0.1Bi and Mg-0.1Zr alloys) and Mg–Mn based ternary alloys (Mg-0.3Mn-0.1Bi and Mg-0.3Mn-0.1Zr alloys). These alloys were processed by hot extrusion to obtain fine-grained structures with an average grain size of ~1 μm. Microstructural observations showed that Mn element was segregated at grain boundaries in the ternary alloys. Precipitates consisting of the α-Mn and/or Mg3Bi2 phase were dispersed in the matrix in the alloys containing Mn and/or Bi elements. All the extruded alloys showed good tensile property of ductility. The elongation-to-failure in tension of Mg-0.3Mn-0.1Zr alloy was more than 100% even at a quasi-static strain rate of 1 × 10−3/s. The Mg-0.1Bi alloy exhibited the largest value of 250% among all in the present examined conditions. These values are superior to those of conventional wrought processed Mg alloys. These superior properties are found to be due to the contribution of grain boundary sliding (GBS) to deformation. Bi and Zr are alternative elements to Mn for use in binary alloys. On the other hand, in low strain rate regimes, a combination of Mn and such micro-alloying elements led to an increase in flow stress, but reduced the elongation-to-failure. This resulted from a high density of precipitates in the matrix, which became cavity nucleation sites. Moreover, non-equilibrium grain boundary structures, which induced atomistic strains, were also unlikely to promote GBS. The normalized stress vs. strain relations including the previous results in the temperature ranges of 298–423 K is found to be fitted by the well-known constitutive equation.