Grain Size Research Articles

Tailoring thermal conductivity and microstructure of Al–Fe alloys by addition of Sc2O3 and variable cooling rates

Al–Fe alloy is a kind of high thermal conductivity alloy, which are widely utilized in the communication and automobile industries. The thermal conductivity is greatly affected by the morphology, size, and distribution of iron-rich intermetallic phases (Fe-rich phases), pores, and Al grains. The evolution of microstructure and thermal conductivity of Al–Fe alloys by adding Sc2O3 particles and adjusting cooling rates are systematically studied by optical and scanning electron microscopy, and synchrotron X-ray imaging. The results show that Sc2O3 addition reduces the size and increases the number of primary Fe-rich phases, while increasing the grain size of Al matrix. The Sc2O3 promote their nucleation of primary Fe-rich phases and partial Sc solutes inhibit their growth, resulting in the improvement of thermal conductivity and mechanical properties. The remaining Sc2O3 particles have large lattice misfit with Al, led to the formation of coarsen size Al. The highest thermal conductivity is 214 W/(m·K) in the alloy with Sc2O3 and slow cooling rate. Sc2O3 addition increase the thermal conductivity of the studied alloys, i.e., an increment of 3 W/(m K) (by 1.1 %) at slow cooling rate by and an increment of 11 W/(m K) (by 6.2 %) at fast cooling rate. This study provides a new strategy to improving thermal conductivity of Al alloy for both academia and industry.

Synergistic optimization of microstructure and mechanical properties of AISI 430 ferritic stainless steel via dual-phase zone annealing process

This study systematically evaluated the impact of dual-phase zone annealing on the microstructure and mechanical properties of cold-rolled 430 Ferritic Stainless Steel (FSS), focusing on the phase transformation process from ferrite to austenite and the dissolution and precipitation behavior of the M23C6 phase. The annealing process significantly affects the microstructural characteristics of ferrite and martensite, including grain size, the distribution of grains of various sizes, aspect ratio, and phase content. The amount of martensite first increased and then decreased with rising annealing temperatures. The sample annealed at 1050 °C exhibited the highest martensite content of 29.5%. The variation in martensite content reflects the complex interplay between phase transformation kinetics and thermodynamic equilibrium. As the annealing time increased or temperature rose, the M23C6 phase at ferrite grain boundaries gradually dissolved and re-precipitated at higher temperatures. At lower temperatures, the M23C6 phase precipitated within martensite, but as the temperature increased, the precipitated phase diminished until it disappeared. Temperature changes affect the solubility of precipitates, atomic diffusion rates, and the uniform distribution of atoms across different phases. Appropriately increasing annealing temperature or extending annealing duration enhances the strength and hardness of 430 FSS. However, excessively high annealing temperatures lead to a decline in mechanical properties. The sample annealed at 1000 °C demonstrated the best mechanical properties, achieving a tensile strength of 783 MPa and an elongation of 16.0%. Furthermore, the analysis of fracture morphology and yield behavior in stress-strain curves further elucidated the macroscopic mechanical performance of the material.

Effect of the Normalizing Temperature on the Size and Homogeneity of Austenite Grain in 20CrMnTi Carburized Gear Steel

Effect of the Normalizing Temperature on the Size and Homogeneity of Austenite Grain in 20CrMnTi Carburized Gear Steel

Achieving bimodal microstructure and enhanced tensile properties of Mg-6Sn-3Al-1Zn alloy by tailoring deformation amount during pack rolling

The Mg-6Sn-3Al-1Zn alloys were pack-rolled with various amounts of deformation at 400°C. The results indicated that a bimodal microstructure formed after pack-rolling. With the increase in the amounts of deformation, the average grain size of the small grains increased first and then decreased, while the average grain size of the big grains decreased. Both the volume fraction of twins and the average grain size of the alloy decreased with the increasing amounts of deformation, resulting in the improvement of the tensile properties of the alloy. When the amount of deformation was 65%, the mechanical properties of the alloys were optimal; the tensile strength, yield strength, and elongation-to-failure were 288 MPa, 188 MPa, and 15.7%, respectively.

Lithochemistry, and gold and sulphides chemistry from the Abiete-Toko Gold District in the NW edge Congo Craton, Nyong Complex (SW-Cameroon): Insights into the primary source of alluvial gold deposits and occurrence in the area

The Abiete-Toko Gold District (ATGD), in the Nyong Complex, NW edge of the Congo Craton, is one of the numerous Cameroonian mining districts producing alluvial gold. Although numerous works were focused on the ATGD alluvial gold deposits, their primary source(s) remain(s) unknown. This study combines the chemistry of pyrite and chalcopyrite which were determined by inductively coupled plasma-mass spectrometry (LA-ICP-MS), the chemistry of alluvial gold grains determined by electron probe microanalysis (EPMA), and whole rock composition determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The results provide the first evidence of gold in the rocks, and its genesis is subsequently discussed. Gold in the ATGD rocks is essentially invisible and lattice bound in pyrite and chalcopyrite, which intake up to 3.11 ppm and up to 32.6 ppm Au, respectively. The gold-bearing metatexites (garnet migmatite) and ultrabasites (serpentinised peridotites) are here therefore, interpreted as possible sources of the ATGD alluvial gold deposits and occurrences. In metatexite, pyrite and chalcopyrite occur within quartz biotite veins, while in ultrabasites pyrite and chalcopyrite are disseminated grains of millimetric sizes, and ovoid or cubic shapes. Gold mineralisation is shear-hosted and, shows evidence of hydrothermal alteration (sulphidation) induced by circulating magmatic and Co-rich (0.01–1.53 %) fluids.

Grain-refined metastable β titanium alloy with suppressed ω-assisted nucleation and enhanced mechanical properties

The mechanical characteristics of metastable β titanium alloys are related to the α precipitates that form during aging. Although precipitation behavior can be modulated by ω-assisted nucleation, the influence of grain size (GS) on this process has not been fully considered. In this study, the effects of grain refinement on mechanical properties and ω-assisted nucleation were investigated by aging the Ti-5.3Cr-4.9Mo-4.9 V-4.3Al-0.9 Nb-0.3Fe (TB18) alloy with coarse grains (87 μm) or fine grains (25 μm) at different heating rates (RH). It was found that ω-assisted nucleation depends on the RH, with a lower RH promoting the processes of ω-assisted nucleation and the precipitation of finer secondary α (αs) plates. The vacancy concentration after annealing reduced with decreasing GS, indicating that ω-assisted nucleation is suppressed by grain refinement. Additionally, grain refinement significantly improved the ductility of the TB18 alloy. This effect was attributed to enhanced homogeneous plastic deformation and an increase in slip systems, such as pyramidal <c+a> slip on αs plates. At ultimate tensile strengths of 1300–1550 MPa, the elongation of the fine-grained specimens was typically 2–3 times greater than that of the coarse-grained specimens. Furthermore, the corresponding mixed fracture mode involved a greater extent of ductile fracture. Therefore, the mechanical properties of metastable β titanium alloys are primarily limited by coarse β grains.

Exceptional thermal stability and hot deformation behavior of a powder metallurgy ultra-fine-grained MoNbTaTiV refractory high-entropy alloy

This work investigates the microstructure evolution and hot deformation behavior of a powder metallurgy (P/M) ultra-fine-grained MoNbTaTiV refractory high-entropy alloy (RHEA), following vacuum heat treatments (VHT). VHT temperature ranged from 1373 to 1573 K for durations of 1–8 h. Isothermal compression tests were conducted at 1573 K with strain rates of 0.005 or 0.0005 s−1. Scanning electron microscopy and transmission electron microscopy images were used to analyze the effect of VHT temperature and time on matrix grain size and precipitated phase evolution. Results showed that both the precipitated phase and matrix grain size exhibited excellent thermal stability in the P/M ultra-fine-grained MoNbTaTiV RHEA. After an 8 h heat treatment at 1573 K, the average sizes of the matrix grain and precipitated phase increased from 180 and 580 nm to 415 and 942 nm, respectively. Precipitated phase size exhibited a strong linear relationship with the cube root of VHT time at a given temperature. Significantly larger precipitated phase sizes were observed at 1573 K compared to 1373 and 1473 K, indicating a degraded pinning effect and a reduction in the matrix grain growth exponent from 10 to 6. However, the matrix grain size remained in the submicron range due to inherent lattice distortion, sluggish diffusion, and precipitated phase pinning effects in high-entropy alloys. Consequently, excellent thermal stability of the microstructure was observed across various VHT conditions, resulting in a constant low-level hot deformation resistance in the studied alloy.

ОТЗЫВЧИВОСТЬ СОРТОВ ПШЕНИЦЫ ПОЛБЫ НА РАСЧЕТНЫЕ ДОЗЫ И СОЧЕТАНИЕ МАКРОЭЛЕМЕНТОВ В УСЛОВИЯХ ПРЕДКАМЬЯ РЕСПУБЛИКИ ТАТАРСТАН

In world agriculture, interest in growing filmy wheat varieties is growing from year to year. One of these types is double-grain wheat (Triticum dicoccum) spelt. This is due to the fact that the grain of this crop contains protein, which includes 18 essential amino acids. The aim of the study is to improve the technology of growing spelt varieties, to determine the parameters of removal of macronutrients from gray forest soils, as well as to clarify the calculated norms of fertilizer application. The research was conducted in 2021-2022 in the Republic of Tatarstan. Agrochemical characteristics of the soil of the experimental site: the humus content according to the Tyurin method is 3.6%, mobile phosphorus is 256...270 mg /kg, potassium is within 125...185 mg/kg according to the Kirsanov method. The acidity of the soil is close to neutral, with a pHsol index of 6.2. The object of research was double-layered spring wheat (spelt) of sample k-10456 and the Fleece variety. Experiments with fertilizers were carried out according to a five-step scheme (Wagner's method): 0; N7K15; N7P7; P7K15; N7P7K15. Against the calculated background of NPK nutrition for obtaining an average of 2.5 t/ha of grain in 2021-2022, the yield of spring wheat of the two-grain k-10456 variety was 2.78 t/ha, and the Fleece variety was 2.58 t/ha. The use of fertilizers made it possible to obtain spelt grains of a larger size, compared with the control. In addition, this did not lead to a significant decrease in the protein content of the grain. The use of mineral fertilizers in combination with N7K15, N7P7 and P7K15 contributed to an average yield increase of 9.7%, 10.2% and 14.6%, respectively. The application of N7P7K15 to spelt crops provided the largest increase in yield - by 0.42 t/ha or 18.6%.

Significant reduction of anisotropy in stress relaxation aging and mechanical properties improvement for 2195 Al-Cu-Li alloy subjected to plastic loading

Although the plastic loading can enhance creep deformation and yield strength, the anisotropic Stress Relaxation Aging (SRA) behavior and mechanism under plastic loading remain unclear, which presents a significant challenge in accurately shaping aluminum alloy panels. In this study, the SRA behavior of 2195-T4 Al-Cu-Li alloys were thoroughly studied under initial loading stresses within the elastic (210/250 MPa) and plastic (380/420 MPa) ranges at 180 ℃ by stress relaxation and tensile tests as well as microstructure characterization. The findings reveal that compared with those under elastic loadings, in-plane anisotropy (IPA) values of the stress relaxation amount, yield strength and fracture elongation under plastic loadings are reduced by 60%-80%, 70%-90% and 72%-89%, respectively. Similarly, IPA values of precipitate size in grains and Precipitation-Free Zones (PFZ) width at grain boundaries under plastic loading decrease by 31.4% and 94.4% respectively. These results indicate plastic loading significantly weakens the anisotropic SRA behavior, owing to numerous uniformly distributed fine T1 phases and small IPA values of both T1 precipitates size and PFZ width in various loading directions. Compared with those of elastic loading-aged alloys, yield strength of plastic loading-aged alloys shows high strength-ductility because of the combined effect of closely dispersed fine T1 precipitates, narrowed PFZ and numerous sheared and rotated T1 phases at different locations during tensile process. The uniformly distributed larger Kernel Average Misorientation (KAM) and Schmidt factor values of the plastic loading-aged alloy, as well as the cross-slip generated, also help to enhance the strength and ductility of the alloy.

Advancing piezoelectric properties of barium titanate ceramic through AC + DC field poling over Curie temperature

The significance of increased domain nucleation sites from smaller grain size (GS) of barium titanate (BT) ceramics on piezoelectric properties was analyzed for different types of poling, including conventional DC poling, modified DC poling, and AC plus DC poling, conducted at different poling temperatures. The AC plus DC poling conducted at 1.5 °C above the Curie temperature (T C) showed the highest piezoelectric constant (d 33) of 528 pC/N, with an average domain size of 100 nm observed after poling. The d 33 improvement was attributed to smaller domain size formation from field-induced phase transitions and homogenous distribution of point defects achieved by the AC field. Comparative analysis with larger grain BT ceramics under AC plus DC poling suggests that defects and volume fraction of grain boundaries in BT ceramics could have an effect on domain sizes.

ESTIMATION OF THE AVERAGE GRAIN SIZES IN METAL AND THEIR DISPERSION BY CHANGING THE AMPLITUDES OF BOTTOM ECHOES OF LONGITUDINAL WAVES WITH A DIFFERENT NUMBER OF REFLECTIONS

A model (algorithm) has been developed for estimating the average size of a metal grain and the spread of its magnitude (standard deviation) according to experimental values of attenuation coefficients due to scattering of longitudinal waves on grains determined by the ratio of the amplitudes of bottom echoes (of the first and higher order) at three frequencies using a table of values of the difference between experimental and calculated values of attenuation coefficients. Computer modeling of the pulse amplitude differences of the 1st and 3rd bottom echoes for normal probe models with nominal frequencies of 5.0, 7.5 and 10.0 MHz and two variants of grain parameters used to test the specified algorithm has been carried out. The results obtained make it possible to choose the optimal operating frequency for metal control by a normal probe based on the estimated value of attenuation of longitudinal waves, determined by the average size of metal grains and the value of its magnitude spread.

Bi3+ doped nanocrystalline Ni–Co–Zn spinel ferrites: Tuning of physical, electrical, dielectric and magnetic properties for advanced spintronics applications

This study reports the synthesis and characterization of nanocrystalline Ni0.5Co0.2Zn0.3BixFe2-xO4 (x = 0.00, 0.025, 0.050, 0.075, 0.100) ferrites synthesized via the sol-gel auto combustion method. The structural, morphological, electric, dielectric, and magnetic properties of Bi3+-doped Ni–Co–Zn spinel ferrites annealed at 700 °C and further sintered at 850 °C, have been investigated towards analyzing the effect of Bi3+ doping. X-ray diffraction (XRD) patterns and Fourier Transform Infrared Spectroscopy (FTIR) spectra have revealed the single-phase cubic-spinel structure of all inspected materials while retaining their high crystalline nature. Their average crystallite size and average grain size are found in the nanoscale range (48–74 nm) and (46–67 nm), respectively. The saturation magnetization (Ms) and experimental magnetic moment (ηexp) are found to decrease with increasing Bi3+ content. The samples sintered at 850 °C display higher AC resistivity, attributing to the reduction of electrons hopping through grains in the samples. The low coercivity values (23.68–87.71 Oe) are observed, classifying the investigated materials as soft ferromagnetic. The increased magnetic anisotropy (K) through Bi3+ doping indicates tunable stability in magnetic orientations, making them suitable for spintronics applications.

Microstructure control and mechanical properties of ultra-nanocrystalline diamond films

Ultra-nanocrystalline diamond (UNCD) films exhibit excellent mechanical properties because of their unique structure, such as small grain size and high grain boundary ratio. The effect of nitrogen atoms in nitrogen-doped UNCD films on their structure and mechanical properties deserves in-depth study. In this study, we focus on the microstructure control of UNCD films and its effect on the mechanical properties. Ultra-nanocrystalline diamond films were prepared using microwave plasma chemical vapor deposition under varying nitrogen flow rates. It was observed that the hardness and elastic modulus of UNCD films initially increased and then decreased with the increase of nitrogen flow rate. The structure of UNCD films was characterized using transmission electron microscopy and the crystal quality was analyzed through Raman spectroscopy. Nitrogen-interstitial atom defects were identified in the photoluminescence spectra. These defects contribute to shorter interatomic bonds and enhance the covalent bonds in the crystalline structure, resulting in an increase in hardness. The sp2/sp3 ratio and effective nitrogen atom concentration in the UNCD film were analyzed by X-ray photoelectron spectroscopy. The results indicate that an increase in the effective nitrogen atom concentration corresponds with a notable reduction in grain size, which is simultaneously accompanied by a rise in the number of grain boundaries. Meanwhile, the increase of sp2 content in the UNCD leads to the increase of grain boundary width and density, resulting in the increase of hardness and elastic modulus. This work provides theoretical basis and experimental guidance for the development of high performance UNCD films through precisely regulating the microstructure.

Optimization of BaZr0.35Ti0.65O3 ferroelectric thin films on energy storage performance by adjusting annealing duration

BaZr0.35Ti0.65O3 (BZT35) ferroelectric thin films were synthesized via the sol-gel process. The phase, morphology and energy storage performance of BZT35 films of various annealing durations were studied, and the effect of annealing duration on these properties was thoroughly discussed. The size of grains in the film increases as the annealing duration prolongs, leading to an increased polarization strength. However, the breakdown field strength descends progressively with increasing annealing duration due to the increase in surface roughness. When annealed for 30 min, the film achieves the maximum polarization difference (16.1 μC/cm2) due to smaller grain size while maintaining good crystallinity, and a large breakdown field strength (3.9 MV/cm) because of its a dense structure and smooth surface. Consequently, this sample exhibits the optimal energy storage performance (Wrec = 31.54 J/cm³ and η = 91 %). The exceptional properties of BZT35 film suggest a promising application in energy storage.

Integrating machine learning and the finite element method for assessing stiffness degradation in photovoltaic modules

This study introduces a novel machine learning (ML) method utilizing a stacked auto-encoder network to predict stiffness degradation in photovoltaic (PV) modules with pre-existing cracks. The input data for the training process was derived from numerical simulations, ensuring a comprehensive representation of module behavior under various conditions. The findings highlight the robust predictive capability of the model, as evidenced by its impressive R2 value of 0.961 and notably low root mean square error (RMSE) of 4.02%. These metrics significantly outperform those of other conventional methods, including the artificial neural network with R2 of 0.905 and RMSE of 9.43%, the space vector machine with R2 of 0.827 and RMSE of 17.93%, and the random forest (RF) with R2 of 0.899 and RMSE of 11.02%. Moreover, the findings suggest that the predictive dynamics of degradation are affected by the varying weight functions of different input parameters, such as climate temperature (CT), grain size (GS), material effort, and pre-crack size, as the degradation level changes. Furthermore, a geometric analysis reveals model deficiencies where significant overestimations correlate with thicker glass components, while pronounced underestimations are predominantly associated with thinner layers of polycrystalline silicon wafer and Ethylene Vinyl Acetate in the module. As a case study, it demonstrated that to maintain a constant degradation level between 1.30 and 1.32 in a PV module with components featuring consistent geometric attributes, the input parameters must be kept within specific ranges: CT ranging from 33 °C to 57 °C, GS ranging from 36 to 81 μm, material effort ranging from 0.74 to 0.81, and pre-crack size ranging from 24 to 32 μm. Therefore, this underscores that the ML model not only predicts degradation but also delineates the parameter space required to achieve a consistent output value.

Polycrystalline silicon, a molecular dynamics study: I. Deposition and growth modes

Polycrystalline silicon (poly-Si) significantly expands the properties of the ICT miracle material, silicon (Si). Depending on the grain size and shape and grain boundary structure, the properties of poly-Si exceed what single-crystal (c-Si) and amorphous (a-Si) silicon can offer, especially for radio frequency (RF) applications in microelectronics. Due to its wide range of applications and, on the one hand, its theoretically and technologically challenging microstructure, poly-Si research is the most timely (Ding et al 2020 Mater. Charact. 161 110174; Zhao and Li 2019 Acta Mater. 168 52–62). In this report, we describe how we simulate and analyse the phenomena and mechanisms that control the effect of poly-Si deposition parameters on the structure of the deposited poly-Si films using classical molecular dynamics simulations. The grain shape and size, degree of crystallinity, grain boundary structure and the stress of poly-Si films are determined depending on the growth temperature, temperature distribution in the growing film, deposition flux, flux variation and the energy transferred to the film surface due to the deposition flux. The main results include: (i) the dependence of the crystallinity profile of the deposited poly-Si films on the stress, temperature and the different parameters of the deposition flux, (ii) growth modes at the early stages of the deposition, (iii) interaction and stability of seed crystallites at the early stage of the deposition of poly-Si films and the transition from the isolated crystallite growth to the poly-Si growth, (iv) interplay of the temperature, crystallinity, crystal shape and heath conductivity of different Si phases, (v) four different stages of crystallite growth are described: nucleation, growth, disappearance and retardation.

Precipitate Dissolution and Grain Growth during Solution Treatment of Ce‐Containing 15Cr–22Ni–1Nb Austenitic Heat‐Resistant Steel

The precipitate dissolution and grain growth during the solution treatment of a newly developed Ce‐containing 15Cr–22Ni–1Nb steel are investigated. The dissolution of eutectic NbC is the result of the elements diffusion along the concentration gradients, and honeycomb (Fe,Cr,Ni,Si)2(Nb,Mo) Laves phase transforms into a more stable Mo2C‐type M2C carbide. As the cerium content is increased from 0 to 0.0630 mass%, the area fraction of eutectic precipitates in forged and solution‐treated 15Cr–22Ni steel is decreased first and then increased. For the steel with 0.0055 mass% cerium content, the substantial reduction in the area fraction of precipitates during hot forging and solution treatment is ascribed to the severe abnormal grain growth. In the case of 15Cr–22Ni steel with 0.0019 and 0.0630 mass% cerium content, the average size of austenite grains after solution treatment is reduced, the multipeak development of grain size distribution is restrained, the range of grain size distribution is narrowed, and the variation coefficient of grain growth, the critical size of abnormally grown grain, and the proportion of abnormally grown grain are all decreased. The variation coefficient of grain growth and the critical size of abnormally grown grain in the steel are increased as the solution time is extended, whereas the proportion of abnormally grown grain presents a general trend of reduction. The established mathematical model of grain growth in the paper can be well applied to predict and control the average size of austenite grains in 15Cr–22Ni steel after solution treatment.

Fabrication of tricobalt tetraoxide thinfilm photocatalyst from cobalt nitrate deposition by a novel spark method

Tricobalt tetraoxide (Co3O4) thinfilm was successfully deposited for the first time by a novel sparking method through a two-step process, which includes cobalt nitrate deposition and subsequent thermal treatment at 300 °C. The formation mechanism of Co3O4 deposition by sparking process from highly pure cobalt wire is elucidated in detail. Deposited Co3O4 thinfilms under different spark repetition rates were intensely characterized and employed as an effective photocatalyst for degradation of organic dye. Notably, the maximum degradation of organic dye was observed for the catalytic thinfilm deposited at low repetition rate owing to its low band gap and porous morphology with smaller size grains, which may lead to the contribution of more charge carriers in the photocatalytic reaction.

Role of Fe supplantation in tailoring structural, electrical conductivity, and magnetic properties in La2Ni1-xFexMnO6 double perovskites

Double perovskite system La2Ni1-xFexMnO6 (x = 0, 0.2, 0.5, 0.8 & 1.0) were developed using sol-gel method. Rietveld refinement revealed monoclinic structure (ordered) along with occurrence of rhombohedral and orthorhombic structures suggesting antisite cationic disorder. Crystallite size and average grain size of samples varied between 454 and 1058 Å and 0.774–1.429 μm respectively. XPS revealed the dual oxidation states of Ni, Fe, and Mn ions. La2NiMnO6 attained the highest DC conductivity among all compositions. The increase in DC conductivity with temperature suggested the semiconducting behavior of the samples, that explained by Thermal Activation (TA) and Variable Range Hopping (VRH) conduction mechanisms. Obtained activation energy(Edc) showed increasing trend with temperature. M-H loops exhibit a ferromagnetic nature accompanied by antiferromagnetic interactions as suggested by exchange bias and partially saturated loops. La2NiMnO6 attained the highest saturation magnetization (29.81emu/g) and decreased with Fe supplantation. The possible mechanism of tuning conductivity and magnetic properties of La2Ni1-xFexMnO6 has been discussed in detail.

Effect of Extrusion Temperature on Microstructure and Mechanical Properties of Mg–Al–Zn Alloy Prepared by Solid‐State Recycling of Mixed Waste Chips

The recycled Mg–Al–Zn alloys are successfully fabricated through solid‐state recycling of mixed waste chips, including cold pressing and hot extrusion. The effects of extrusion temperature on the microstructure evolution, slip mode, tensile properties, and hardness are studied. The homogeneous fine dynamic recrystallization (DRXed) grains with an average grain size of less than 13.1 μm can be obtained at four different extrusion temperatures (250, 300, 350, and 400 °C). The average grain size of the DRXed grains continuously increases with the rising extrusion temperature. However, the yield strength (YS), ultimate tensile strength (UTS), and elongation to failure (EL) of the recycled alloys increase first and then decrease. The recycled Mg–Al–Zn alloys at 350 °C demonstrate excellent mechanical properties with the YS of 134.6 MPa, UTS of 286.2 MPa, EL of 7.4%, and Vickers hardness of 75.2 HV, respectively. In addition, the slip mode is transformed from the previous basal slip to the coactivation of multiple slips composed of the basal slip, prismatic slip, and pyramidal slip with the rising extrusion temperature.