Weak Basal Texture Research Articles

Effect of lanthanum oxide on microstructure and mechanical properties of ZK60 magnesium alloy

Different amounts of La2O3 were added to ZK60 alloy to observe the changes in microstructure and mechanical properties of ZK60-XLa2O3 (X = 0, 0.2 wt%, 0.5 wt%) composites. Our findings reveal that within the as-cast ZK60 alloy, the Mg-Zn binary phase is manifested as rod-shaped precipitates, exhibiting a dispersed distribution predominantly along the grain boundary regions. With the increase of La2O3 addition, the rod-like Mg-Zn binary phases are gradually replaced by Mg-Zn-La ternary phases, and these Mg-Zn-La ternary phases are semi-continuously distributed around the grain boundaries. Both ZK602 and ZK605 alloys result in a corresponding improvement in ductility after extrusion. It is noteworthy that the ductility of the as-extruded ZK605 alloy is increased by 59.4% compared to ZK60 at the expense of a reduction of only 3.9% in yield strength. Taken together, the significant increase in ductility of ZK605 is mainly due to the weakening of the basal texture, which is weakened by the redox reaction of La2O3 with the α-Mg matrix, generating the La element. The decrease in yield strength of ZK605 in the extruded state is closely related to the observed grain coarsening phenomenon and the basal texture weakening. At the same time, the ultimate tensile strength of ZK605 shows a slight increase, which is mainly due to the second phase strengthening. The Mg-Zn-La ternary phase exhibits a notably hard character, and it is evident that the distribution of this phase becomes progressively denser as the La2O3 content increases.

The Role of Deformation and Microstructure Evolution on Texture Formation of a TA15 Alloy Subjected to Plane Strain Compression.

In this study, the texture formation mechanism of a TA15 titanium alloy under different plane strain compression conditions was investigated by analyzing the slipping, dynamic recrystallization (DRX) and phase transformation behaviors. The results indicated that the basal texture component basically appears under all conditions, since the dominant basal slip makes the C-axis of the α grain rotate to the normal direction (ND, i.e., compression direction), but it has a different degree of deflection. With an increase in deformation amount, temperature or strain rate, {0001} poles first approach the ND and then deviate from it. Such deviation is mainly caused by a change in slip behaviors and phase transformation. At a smaller deformation amount and higher strain rate, inhomogeneous deformation easily causes a basal slip preferentially arising from the grain with a soft orientation, resulting in a weak basal texture component. A greater deformation amount can increase the principal strain ratio, thereby promoting other slip systems to be activated, and a lower temperature can increase the critical shear stress of the basal slip, further causing a dispersive orientation under these conditions. At a higher temperature and a lower strain rate, apparent phase transformation will induce the occurrence of lamellar α whose orientation obeys the Burgers orientation of the β phase, thereby disturbing and weakening the deformation texture. As for DRX, continuous-type (CDRX) is most common under most conditions, whereas CDRX grains have a similar orientation to deformed grains, so DRX has little effect on overall texture. Moreover, the microhardness of samples is basically inversely proportional to the grain size, and it can be significantly improved as lamellar α occurs. In addition, deformed samples with a weaker texture present a higher microhardness due to the smaller Schmidt factors of the activated prism slip at ambient loading.

Track-Rex: A universal toolbox for tracking recrystallization nucleation and grain growth behaviors in polycrystalline materials

Recrystallization annealing is widely used to tailor the microstructure and enhance the performance of cold-deformed metallic materials. However, the underlying recrystallization mechanisms are debated, even with the use of cutting-edge characterization techniques. Here, we develop a Track-Rex toolbox to analyze quasi-in-situ electron backscatter diffraction (EBSD) datasets of two magnesium (Mg) alloys during static recrystallization via grain correlation. The results show that the recrystallized grains do not always grow; instead, they can shrink or even be consumed. This is attributed to the presence of newly formed recrystallized grains that possess a growth advantage over the old recrystallized grains. The rare earth containing Mg-2.4Zn-0.2Ce wt.% (ZE20) alloy exhibits a higher nucleation activity in the shear bands compared to the commercial Mg-3Al-1 Zn (AZ31) alloy. Regardless of the nucleation timing and sites, recrystallized grains in the ZE20 alloy show consistent off-basal orientations, serving as the origin of the rare earth texture. Moreover, the off-basal texture of these recrystallized grains is further strengthened through preferential growth during subsequent annealing. On the contrary, the recrystallized grains in the AZ31 exhibit scattered basal orientations that grow uniformly, resulting in a weak basal texture.

Effect of extrusion ratio on microstructure, texture, and mechanical properties of dual-phase Mg−8Li−6Zn−2Gd alloy

The microstructure observation, macrotexture analysis, and tensile test were conducted to investigate the effect of extrusion ratio on the microstructure, texture, and mechanical properties of Mg−8Li−6Zn−2Gd alloy. The results show that the as-homogenized Mg−8Li−6Zn−2Gd alloy consists of α-Mg, β-Li, MgLiZn, I-phase, and W-phase. After hot extrusion, eutectic I-phase is broken into fine particles, while W-phase maintains massive shape. Both α-Mg and β-Li matrices undergo dynamic recrystallization (DRX), and their grains gradually refine with increasing extrusion ratio. For α-Mg matrix, the weakening of basal texture and the strengthening of prismatic texture after hot extrusion are due to the activation of non-basal slip. For β-Li matrix, the appearance of obvious α and γ fiber textures after hot extrusion is associated with the dynamic recovery (DRV) and DRX. The tensile strength and elongation of the alloy are simultaneously improved by hot extrusion, and the best comprehensive mechanical properties are achieved when extrusion ratio is 16:1.

Microstructure evolution and deformation behaviors of AZ31 Mg alloy sheets processed by repeated bending−flattening deformation with different die angles

AZ31 magnesium alloy sheets were fabricated by repeated bending−flattening deformation (RBFD) using dies of various angles. The microstructure evolution and deformation behaviors of the AZ31 Mg alloy during RBFD were investigated by FEM, OM, EBSD and hardness tester. The results suggest that the 150°/150° die exhibits the superior performance across all three groups. With an increase in passes, the effective strain of the alloy is significantly improved due to the positive impact of shear and bending. After four passes, the average grain size can be significantly refined to 1.7 μm, and a weaker basal texture can be obtained compared to the initial one due to non-basal slips, dynamic recrystallization (DRX), and twinning. Particularly, the pyramidal 〈c+a〉 slip promotes DRX and twinning. The hardness of the alloy reaches HV 77 as a result of the comprehensive effect of microstructure and texture generated by slip, twinning and DRX competition.

Extrusion limit diagram of Mg–5Bi–3Al–1Zn alloy and effects of extrusion parameters on its microstructures and mechanical properties

Hot-compressive tests and finite element simulations were carried out to construct an extrusion limit diagram of a Mg–5Bi–3Al–1Zn (wt.%) alloy in this work. It was observed that 310 °C became a dividing line, below which the safe extrusion zone was narrow because the stress required to induce the plastic flow of alloy was higher than the pressure limit. Once the temperature exceeded this critical temperature, a wide safe extrusion zone controlled by the cracking limit was attained. The theoretical maximum ram extrusion speed was calculated as approximately 48 mm/s at 310 °C. No hot cracks occurred on the surface of alloys extruded at 30 and 44 mm/s; while at 56 mm/s, obvious orange peel defects were observed. Through further microstructural observation, the 44 mm/s extruded alloy exhibited a complete dynamic recrystallization structure with an average grain size of 21.9 μm, along with a relatively weak basal fiber texture (with a maximum pole intensity of 5.8) and plentiful nano-Mg3Bi2 phases. These microstructure features led to superior tensile properties (namely a tensile yield strength of 270 MPa, an ultimate tensile strength of 375 MPa and an elongation of 15%) at the high-speed extrusion.

Significant improvement of bending properties for WE43 magnesium alloys under the coupling effects of weak basal texture and high deformation temperature

Significant improvement of bending properties (approximately 64.7%) for WE43 magnesium alloy was realized by weakening the basal texture and raising the deformation temperature. The mechanisms for such improvement were investigated in detail by combining the experiment and finite element model. The results concluded that the coupling effects of weak basal texture and high deformation temperature was the key reason producing the above improvement of bending properties. Specially, the TD sample with weak basal texture was more conducive to activating basal slip than the RD sample, resulting in its higher strain hardenability and consequently more significant bending properties. Based on weak basal texture, raising the deformation temperature could further improve the bending properties. This improvement mechanism was attributed to the abundant activations of non-basal slip instead of basal slip, which could increase the independent slip systems and efficiently delay the development of the strong basal texture. Moreover, the occurrence of partial DRV and DRX relieved the stress concentrations by consuming the dislocations, further improving the bending properties. The activations of these deformation mechanisms matching the corresponding bending stress states caused the crystal rotation and the texture variety in the bending samples. Basal slip activation aligned the (0002) basal planes parallel to tensile stress in the outer region or perpendicular to compressive stress in the inner region. Additionally, prismatic slip activation induced crystal rotation around the c-axis, developing <10-10>//LD texture in the outer region but <10-10>⊥LD texture in the inner region.

Unveiling the microstructure evolution and deformation mechanisms of micro-alloying Mg-1.5Zn-0.5Zr-0.5Sr alloy via extrusion-shearing

Obtaining high strength without sacrificing ductility in Mg alloys is of great importance. However, the hexagonal close-packed crystal structure critically limits the deformation of Mg alloys. In this work, novel Mg-1.5Zn-0.5Zr-0.5Sr (wt.%) alloys were fabricated through homogenization, direct extrusion (DE), and extrusion-shearing (ES) processes. The effects of three different processes on microstructures, texture, and mechanical properties were thoroughly investigated. The results show that the average grain size of the alloy was greatly refined after hot extrusion. The alloy after the DE process exhibited a typical bimodal microstructure with dynamic recrystallized (DRXed) grains showing a strong <101‾0 > fiber texture parallel to extrusion direction (ED), while the small-sized unDRXed grains showed relatively weak basal texture. In addition, the strength was significantly improved, with the value of yield strength (YS) reaching ∼229 MPa and ultimate tensile strength (UTS) reaching ∼262 MPa. This is mainly attributed to grain boundary strengthening and dislocation strengthening. Compared to the DE-processed alloy, the basal texture intensity was significantly decreased and non-basal slip was activated after the ES process, which indicates that the shearing deformation during ES could improve the ductility, with the fracture elongation (FE) increased from ∼13.9 % to ∼21.4 %. This work aims to unveil the deformation mechanisms in Mg-1.5Zn-0.5Zr-0.5Sr alloy and provides an efficient way for preparing micro-alloying Mg alloys with low cost and significant improvement of comprehensive properties.

Improving the tension-compression asymmetry of ZK61 magnesium alloy through texture optimization in combined extrusion

In order to improve the tension-compression asymmetry that exists widely in extruded magnesium alloys, ZK61 magnesium alloys with different texture characteristics were prepared by conventional extrusion, compression-extrusion, and cyclic extrusion compression. The effect of texture on the tension-compression asymmetry and associated deformation mechanisms of magnesium alloys was revealed based on the Sachs assumption. Subsequently, a texture-modified Hall-Petch relationship was used to quantify the combined effect of texture and grain on both tensile and compressive yield strengths. It is found that the slight weakening of the {0002}∥LD fiber texture was beneficial to the suppression of {10‐12} twinning and the activation of prismatic slip, which in turn significantly improved the tension-compression asymmetry without the obvious sacrifice of strength. However, excessive texture inclining can cause a striking decrease in strengths and even reverse tension-compression asymmetry due to the activation of basal slip and pyramidal slip. In conclusion, slight basal texture weakening was a texture optimization strategy to obtain tension-compression symmetry and high strength for wrought magnesium alloys.

Revealing the effect of misorientation on the deformation behavior of a Mg-Y alloy from the perspective of local strain

The addition of rare earth (RE) elements in magnesium alloys may significantly enhance the ductility of magnesium alloys, which is generally attributed to the decrease of stacking fault energy, the reduced critical resolved shear stress (CRSS) differences among different deformation modes and the weakening of basal texture. Rare earth elements also change the misorientation between adjacent grains of magnesium alloy, whose effects on the deformation behavior and thus the ductility of magnesium alloy were not emphasized before. In this work, ex-situ high-resolution digital image correlation (HR-DIC) coupled with electron backscatter diffraction (EBSD) was used to reveal the effect of the misorientation on the deformation behavior of a Mg-Y binary alloy from the perspective of local strain. It is shown that the heterogeneity of local strain is largely dependent on the misorientation between adjacent grains. For the intergranular deformation, three scenarios are observed, namely strain transfer, strain concentration and suppressed deformation, which mainly occurs at low misorientation, moderate misorientation and high misorientation, respectively. In addition, much more non-basal slip is found to be activated near the grain boundaries with moderate misorientation angles due to the high geometric compatibility factor (m’B-Pr/Py), which is favorable for the intergranular deformation compatibility, thus reducing the strain concentration near grain boundaries and achieving high ductility. For the intragranular deformation, a wide range of misorientation between adjacent grains in the Mg-Y alloy causes multiple basal slip systems to be activated within a grain, which also facilitates work hardening, thus contributing to improving ductility. Therefore, tailoring the misorientation between adjacent grains may be an effective way to improve the ductility of magnesium alloys.

Improving low-cycle fatigue life of ZK61 magnesium alloy via basal texture weakening by the compression-extrusion process

In response to the problem that intense basal texture seriously affects the low-cycle fatigue life of magnesium alloys, the compression-extrusion process for basal texture weakening was implemented in ZK61 magnesium alloys. The low-cycle fatigue life under uniaxial symmetrical tension-compression cyclic loading was dramatically improved by basal texture weakening, up to 1.5∼3 times that in an intense-textured state. Basal texture weakening promoted basal slip to dominate the cyclic deformation, thus significantly reducing the cyclic tension-compression asymmetry caused by the {10–12} twinning-detwinning. Further, the suppression of {10–12} twinning and the decrease of compressive plastic strain slowed down dislocation accumulation inhibiting the cyclic hardening and fatigue crack initiation. The Manson-Coffin equation was feasible to predict the fatigue life of the intense-textured and weak-textured ZK61 magnesium alloys. The promotion of basal slip arising from basal texture weakening led to the decrease of fatigue ductility coefficient and the increase of fatigue ductility exponent contributing to the higher fatigue life.

Achieving high strength near 400 MPa in an ultra-fine grained Mg–Bi–Ca ternary alloy via low-temperature extrusion

Significantly enhancing the mechanical properties of Mg–Bi base series alloys is of great significance for their wider application prospects. Here, a new Mg–3Bi–1Ca (BX31, wt.%) alloy showing high tensile yield strength of ∼397.1 MPa, high ultimate tensile strength of ∼416.2 MPa and acceptable elongation of ∼8% was fabricated by low-temperature extrusion. The analysis of microstructure showed that the enhanced yield strength was attributed to the ultra-fine grain structure (∼0.84 μm), nano-scale second phases including Mg2Bi2Ca and Mg2Ca, and Ca segregation at grain boundaries. In addition, a weak basal fiber texture to some extent provided more basal slip activities, guaranteeing the suitable ductility. The dynamic recrystallization and dislocation behavior of the BX31 billet during extrusion were also systematically observed and discussed to reveal the formation mechanisms of the ultra-fine grain structure with the weak basal fiber texture in the as-extruded BX31 alloy. As mentioned above, this work offers a new insight to obtain high-performance Mg–Bi base series alloys.

Effect of long-term natural aging on the microstructural characteristics of an extruded WE54 alloy

The microstructure and the corresponding crystallographic texture of the as-extruded WE54 alloy after natural aging for 11 years at room temperature have been characterized by the Electron backscatter diffraction (EBSD) technique. Before natural aging, the as-extruded WE54 exhibited equiaxed microstructure with a strong splitting basal texture and the presence of second particles along the extrusion direction (ED). Unexpectedly, long-term aging led to the formation of elongated deformed grains along ED having {11–20}<10-10> and {0001}<10-10> orientations with a partial development of fine static recrystallized grains by continuous and discontinuous mechanisms. It is believed that the origin of such grain structure development is the residual stored strain during the extrusion processing and the strain field induced from the solute Nd and Y atoms diffusion through the long-term natural aging. Artificial aging at 400 °C for 60 min demonstrated that the elongated deformed grains disappeared and left behind a heterogeneous recrystallized microstructure with a weak basal texture.

The improvement on mechanical anisotropy of AZ31 magnesium alloy sheets by multi cross-rolling process

The rolled AZ31 Mg alloy sheets were manufactured by unidirectional rolling and cross-rolling with two passes and five passes in this study. The improvement of multi cross-rolling on the anisotropy of mechanical properties, microstructure and texture of AZ31 Mg alloys was investigated by tensile fracture experiments, optical microscopy (OM) and electron backscatter diffraction (EBSD). The results indicate that the samples after rolling which were rotated by 90° showed weaker anisotropy than the samples rolled by 0° path. The ultimate tensile strength of the samples after 0° direction rolling increased from 236 MPa to 338 MPa on the transverse direction (TD) compared to as-rolled samples. The ultimate tensile strength of unidirectional rolling samples with two and five passes paralleled to TD is increased by 7% and 14% than that of cross-rolling samples. The enhanced mechanical properties are attributed to fine-grained strengthening, twin strengthening and dislocation strengthening. The {10−12} extension twin, {10−11} contraction twin and {10−12}-{10−11} double twin were investigated in the microstructure of samples by multi cross-rolling. All the samples showed the basal texture on the {0001} < 11–20 > . The basal texture of cross-rolling samples was apparently weakened for comparison to unidirectional rolling samples and the basal texture of five-pass cross-rolling samples was weaker than that of two passes. The improvement of anisotropy after cross-rolling can be attributed to grain refinement, the activation of non-basal slip and the weakening of basal texture.

Texture weakening and ductility improvement of Mg-1.1Mn-0.5Al alloy via medium temperature-high reduction rolling: twinning variants selection and dynamic recrystallization mechanism

The weakening of basal texture is beneficial to improve the formability and mechanical properties of deformed magnesium alloys. In this paper, the microstructure and texture evolution of single pass rolled Mg-1.1Mn-0.5Al alloys with various reduction of 10%–60% at 200 °C were observed to reveal twin variants selection and mediated dynamic recrystallization (DRX) mechanism. The results showed that the type and volume fraction of activated twins were strongly related to rolling reduction. Primary {101¯2} tensile twins (TTWs), which were mainly activated in the 10% reduction rolled alloys, were not sufficient to induce recrystallization due to the absence of cumulative dislocation and lower plastic strain energy. In contrast, {101¯1}/ {101¯3} compression twins (CTWs) and {101¯1}−{101¯2}/ {101¯3}−{101¯2} double twins (DTWs) were preferred for recrystallization because of higher dislocation accumulation and stored strain energy. The occurrence of DRX was beneficial to absorb stored energy, relax stress concentration and weaken basal texture in adjacent domains. Due to the sufficient stress provided by massive basal slip dislocations, the type I and type II DTWs were more commonly observed than the type III and type IV variants, which involved much more dissociations of the mixed <c+a> dislocations in deformed magnesium alloys.

Unexpectedly formed strong basal texture in a rolled Mg-Zn-Ca-Mn alloy sheet

The reheating at high temperature, which contributed to the significant texture weakening in rolled Mg alloys, was used to control the textural features of a Mg-Zn-Ca-Mn alloy sheet. The grain coarsening was apparent when the alloy was reheated at high temperature of 450 °C, facilitating the formation of double twinning and shear bands during rolling. Double twinning and shear bands generally cause the weakening of basal texture after post-annealing; however, the basal texture became strong in the Mg-Zn-Ca-Mn alloy sheet rolled with reheating at 450 °C. The electron backscattered diffraction revealed that the non-uniformly distributed dislocations caused such unexpected textural development. In contrast, when the reheating was performed at 350 °C, the alloy formed uniform deformation-microstructure after rolling, contributing to the apparent texture weakening by the static recrystallization at double twinning during post-annealing.

Dynamic recrystallization and twinning behavior of magnesium alloy during hot tension

In this study, {10–12} tensile twins (TTs) were induced in hot-rolled AZ31 Mg sheets via hot tension along the normal direction. The results demonstrate that the volume fraction of TTs at 2 mm/min is greatly lower than their counterparts at 0.5 mm/min at 100 °C and 200 °C. Dynamic recrystallization (DRX) can decrease twin nucleation rate during hot tensile when the strain rate reaches 2 mm/min. Decrease in critical resolved shear stress of non-basal slips at 200 °C enhances the deformation capability among grains, which dramatically reduces the volume fraction of TTs. Hence, TTs are hardly observed in 200°C-2mm/min sample. Tensile temperature significantly affects the morphology of TT lamellae. Grain boundaries prevents the longitudinal growth of the TTs, and then the thickness of TTs begins to grow to coordinate the deformation, resulting in fine TT lamellae in 100°C-0.5 mm/min. Compared with AR, the basal texture intensity of 100°C-2mm/min and 200°C-2mm/min increases and the occurrence of DRX is the main reason, while basal texture weakening of 100°C-0.5 mm/min and 200°C-0.5 mm/min depends on the formation of TTs. Compared with samples at 200 °C, the samples at 100 °C have higher tensile stresses. The maximum stress of 100°C-0.5 mm/min is 64.97 MPa when tensile strain reaches 0.15 owing to its highest dislocation density. 200°C-2mm/min possesses the highest hardness among the four tension samples, which is associated with the largest fraction of DRXed grains (68.8%) and its refinement strengthening effect. Dislocation strengthening exerts more influence on the hardness of 100°C-0.5 mm/min.

The recrystallization, texture and mechanical behavior of hot rolled and annealed Mg-10Ho binary alloy

The recrystallization, texture, and mechanical properties of hot-rolled and hot-rolled + annealed Mg-10Ho (wt %) are investigated. Mg-10Ho binary alloy is first solution treated followed by multipass rolling at 420 °C for up to 50 % reduction and subsequently annealed at 400 °C for different times for up to 60 min. The microstructure of deformed and annealed samples was characterized using a field-emission secondary electron microscope (FESEM) and electron back-scattered diffraction (EBSD) and the mechanical properties were examined using hardness and tensile tests. The as-rolled microstructure contains fine dynamic recrystallized grains and different types of deformation twins. With increasing annealing time, a decrease in the hardness was observed, suggesting initiation of recovery and static recrystallization. After 10 min of annealing, an equiaxed, nearly fully recrystallized microstructure with a grain size of 14 µm and weaker basal texture was obtained. This annealed sample exhibits an ultimate tensile strength of 213 MPa, yield strength of 145 MPa, and ductility of ∼7 %. Such an optimum combination of strength and ductility is attributed to the combined effect of solid solution strengthening, grain refinement, and texture weakening. Additionally, the Johnson-Mehl-Avrami-Kolmogorov (JMAK) model was used to understand the recrystallization kinetics of Mg-10Ho and compared it with that of Mg-10Y. Results indicate that the solute drag effect plays a dominant role in the faster recrystallization kinetics of Mg-10Ho alloy. Finally, the texture variation in Mg-10Ho and Mg-10Y is also explained based on the solute drag effect.

Simultaneously improving yield strength and formability potential of Mg alloy via introducing nano precipitates and texture-weakened heterogeneous grains

Simultaneously improving the yield strength (YS) and formability at room temperature of magnesium (Mg) alloys is one of the key issues to broaden the application further. In this work, we report a new hot-extruded + annealed alloy (i.e., Mg–2Sm–0.8Mn–0.6Ca–0.5Zn) having good combination of yield strength (YS: 167 MPa) and formability potential (UTS−YS: 115 MPa and elongation: 25%), mainly due to formation of nano precipitates and texture-weakened heterogeneous grains. The results indicate that introduction of a certain amount of nano precipitates can enhance the strength of the alloy with little detrimental effect on ductility. The formation of heterogeneous-grained structure with a weak basal texture is mainly related to Sm/Zn/Ca elements grain boundary (GB) segregation. Geometrically necessary dislocations would nucleate at grain boundaries due to uneven deformation behavior caused by heterogeneous-grained structure, obtaining additional hetero-deformation induced hardening and large work-hardening capacity. Formation of heterogeneous-grained structure and solid solution of Sm/Zn/Ca promote the activation of considerable non-basal slips and the suppression of twinning during the deformation process. Meanwhile, GB segregation is conducive to dislocation nucleation from GBs and suppression of the GB cracking. All of these contribute to the high elongation. Thus, we put forwards a new strategy for improving the YS and formability potential via introducing nano precipitates and texture-weakened heterogeneous grains.

Comparison of the Strain Rate Sensitivity in AZ31 and WE43 Magnesium Alloys under Different Loading Conditions

The initial texture effect of strain rate sensitivity response in magnesium alloys was studied using the quasi in situ electron backscatter diffraction technique. The strain accumulations, under uniaxial loading of both tensile and compression along the rolling direction, showed strain rate dependency. For the AZ31 magnesium sheets with strong basal texture (max intensity to 11.2), twinning first occurs at the onset of plastic deformation, resulting in macroscopic strain rate insensitivity. With further loading, the strain rate sensitivity significantly increases (with the strain rate sensitivity coefficient m increased from 0.0025 to 0.012), arising from the initiation of slip. For the WE43 alloy sheets with weak basal texture (max intensity to 2.6), the overall deformation is sensitive to strain rate under both tensile and compression. The twinning growth rate and twinned volume fraction have been used to identify whether the process is twin-dominated or slip-dominated during the plastic deformation of a magnesium alloy.