Microstructures and mechanical properties of Mg-Al-Sm series heat-resistant magnesium alloys

The microstructures and phase compositions of the as-cast and die-cast Mg-6.02Al-1.03 Sm, Mg-6.05Al-0.98Sm-0.56 Bi and Mg-5.95Al-1.01Sm-0.57 Zn alloys were investigated. Meanwhile, the tensile mechanical and flow properties were tested. The results show that the as-cast microstructure of Mg-6.02Al-1.03 Sm alloy is composed of δ-Mg matrix, discontinuous δ-Mg17Al12 phase and small block Al2 Sm phase with high thermal stability. Rod Mg3Bi2 phase precipitates when Bi is added, while the added metal Zn dissolves into δ-Mg matrix and δ-Mg17Al12 phase. The as-cast alloys exhibit the excellent tensile mechanical property. The tensile strength（δb） and elongation（δ） can reach 205-235 MPa and 8.5%-16.0% at ambient temperature, respectively. Meanwhile, they can also exceed 160 MPa and 14.0% at 423 K, respectively. The die-cast microstructures are refined obviously, and meanwhile the broken second phases distribute dispersedly. The die-cast alloys exhibit better tensile mechanical properties with the values of δb and δ of 240-285 MPa and 8.5%-16.5% at ambient temperature, respectively, and excellent flow property with the flow length of 1870-2420 mm. The die-cast tensile fractures at ambient temperature exhibit a typical character of ductile fracture.

Effects of pre-deformation on microstructure and properties of Al–Cu–Mg–Ag heat-resistant alloy

The effects of the pre-deformation on the microstructure, mechanical properties and corrosion resistance of Al–Cu–Mg–Ag alloys were investigated by means of hardness tests, tensile tests, intergranullar corrosion (IGC) tests and transmission electron microscopy (TEM), respectively. The results show that with the increase of deformation amount, the aging hardening rate increases while the strength of the alloy decreases and then increases. The sample with a pre-deformation of 6% possesses the highest tensile strength due to the refinedly and homogeneously distributed precipitations. The pre-deformation aging accelerates the heterogeneous nucleation of Ω and θ′ phases at dislocations, and also refines the precipitations both in the grains and along the grain boundaries. The precipitation of Ω phase is restrained while that of θ′ phase is accelerated in pre-deformed Al–Cu–Mg–Ag alloy compared with the sample without pre-deformation. In addition, the width of the precipitate free zone decreases with increasing the pre-deformation amount, leading to a narrower IGC passageway. This results in an enhanced IGC resistance of Al–Cu–Mg–Ag alloy treated by pre-deformation aging. © 2017, Central South University Press and Springer-Verlag GmbH Germany.

Revealing the role of pyramidal slip in the high ductility of Mg-Li alloy

The high ductility of Mg-Li alloy has been mainly ascribed to a high activity of pyramidal<c+a>slip to accommodate plastic strain.In the present study,however,a quantitative analysis reveals that Li-addition can only slightly stimulate the activation of pyramidal<c+a>slip under compression along the normal direction of a hot-rolled Mg-4.5 wt.%Li plate,with a relative activity of approximately 18%.Although the limited activity of pyramidal<c+a>slip alone cannot accommodate a large plastic strain,it effectively reduces the number of{10.11}−{10.12}double twins,which are believed to be favorable sites for crack initiation.The evidently reduced activity of double twins leads to a lower cracking tendency,and therefore improves ductility.

Effect of characteristics and distribution of Mg_(17)Al_(12)precipitates on tensile and bending properties of high-Al-containing Mg alloys

This study investigates the effect of characteristics and distribution of Mg_(17)Al_(12)precipitates on the uniaxial tensile and three-point bending properties of extruded Mg alloys containing high Al contents.The extruded Mg–9Al–1Zn–0.3Mn(AZ91)alloy contains lamellar-structured Mg_(17)Al_(12)discontinuous precipitates along the grain boundaries,which are formed via static precipitation during natural air cooling.The extruded Mg–11Al–1Zn–0.3Mn(AZ111)alloy contains spherical Mg_(17)Al_(12)precipitates at the grain boundaries and inside the grains,which are formed via dynamic precipitation during extrusion.Due to inhomogeneous distribution of precipitates,the AZ111 alloy consists of two different precipitate regions:precipitate-rich region with numerous precipitates and finer grains and precipitate-scarce region with a few precipitates and coarser grains.The AZ111 alloy exhibits a higher tensile strength than the AZ91 alloy because its smaller grain size and more abundant precipitates result in stronger grain-boundary hardening and precipitation hardening effects,respectively.However,the tensile elongation of the AZ111 alloy is lower than that of the AZ91 alloy because the weak cohesion between the dynamic precipitates and the matrix facilitates the crack initiation and propagation.During bending,a macrocrack initiates on the outer surface of bending specimen in both alloys.The AZ111 alloy exhibits higher bending yield strength and lower failure bending strain than the AZ91 alloy.The bending specimens of the AZ91 alloy have similar bending formability,whereas those of the AZ111 alloy exhibit considerable differences in bending formability and crack propagation behavior,depending on the distribution and number density of precipitates in the specimen.In bending specimens of the AZ111 alloy,it is found that the failure bending strain(ε_(f,bending))is inversely proportional to the area fraction of precipitates in the outer zone of bending specimen(A_(ppt)),with a relationship ofε_(f,bending)=–0.1A_(ppt)+5.86.

Study on the low mechanical anisotropy of extruded Mg-Zn-Mn-Ce-Ca alloy tube in the compression process

In this study,the extruded Mg-Zn-Mn-Ce-Ca alloy tube with a low compression anisotropy along the ED,45ED and TD was prepared.The effect of the second phases,initial texture and deformation behavior on this low mechanical anisotropy was investigated.The results revealed that the alloy tube contains the high content(Mg1-xZnx)11Ce phase and the low content of Mg12Ce phase.These second phases are respectively incoherent and coherent with the Mg matrix,and their influence can be ignored.Additionally,the alloy tube exhibited a weak basal fiber texture,where the c-axis was aligned along the 0°∼30°tilt from TD to ED.Such a texture made the initial deformation(at 1.0%∼1.6%strain)of the three samples controlled by comparable basalslip.As deformation progressed(1.6∼9.0%strain),larger amounts of ETWs nucleated and gradually approached saturation in the three samples,re-orienting the c-axis to a 0°∼±30°deviation with respect to the loading directions.Meanwhile,the prismatic and pyramidal<c+a>slips replaced the dominant deformation progressively until fracture.Eventually,the similar deformation mechanisms determined by the weak initial texture in the three samples contribute to the comparable strain hardening rates,resulting in the low compressive anisotropy of the alloy tube.

Greatly enhanced corrosion/wear resistances of epoxy coating for Mg alloy through a synergistic effect between functionalized graphene and insulated blocking layer

The poor corrosion and wear resistances of Mg alloys seriously limit their potential applications in various industries.The conventional epoxy coating easily forms many intrinsic defects during the solidification process,which cannot provide sufficient protection.In the current study,we design a double-layer epoxy composite coating on Mg alloy with enhanced anti-corrosion/wear properties,via the spin-assisted assembly technique.The outer layer is functionalized graphene(FG)in waterborne epoxy resin(WEP)and the inner layer is Ce-based conversion(Ce)film.The FG sheets can be homogeneously dispersed within the epoxy matrix to fill the intrinsic defects and improve the barrier capability.The Ce film connects the outer layer with the substrate,showing the transition effect.The corrosion rate of Ce/WEP/FG composite coating is 2131 times lower than that of bare Mg alloy,and the wear rate is decreased by~90%.The improved corrosion resistance is attributed to the labyrinth effect(hindering the penetration of corrosive medium)and the obstruction of galvanic coupling behavior.The synergistic effect derived from the FG sheet and blocking layer exhibits great potential in realizing the improvement of multi-functional integration,which will open up a new avenue for the development of novel composite protection coatings of Mg alloys.

Synergistic effect of gradient Zn content and multiscale particles on the mechanical properties of Al-Zn-Mg-Cu alloys with coupling distribution of coarse-fine grains

This study investigated the influence of graded Zn content on the evolution of precipitated and iron-rich phases and grain struc-ture of the alloys,designed and developed the Al–8.0Zn–1.5Mg–1.5Cu–0.2Fe(wt%)alloy with high strength and formability.With the increase of Zn content,forming the coupling distribution of multiscale precipitates and iron-rich phases with a reasonable matching ratio and dispersion distribution characteristics is easy.This phenomenon induces the formation of cell-like structures with alternate distribu-tion of coarse and fine grains,and the average plasticity–strain ratio(characterizing the formability)of the pre-aged alloy with a high strength is up to 0.708.Results reveal the evolution and influence mechanisms of multiscale second-phase particles and the corresponding high formability mechanism of the alloys.The developed coupling control process exhibits considerable potential,revealing remarkable improvements in the room temperature formability of high-strength Al–Zn–Mg–Cu alloys.

Mechanism of microarc oxidation on AZ91D Mg alloy induced byβ-Mg_(17)Al_(12) phase

This work proposed a strategy of indirectly inducing uniform microarc discharge by controlling the content and distribution ofβ-Mg_(17)Al_(12)phase in AZ91D Mg alloy.Two kinds of nano-particles(ZrO_(2)and TiO_(2))were designed to be added into the substrate of Mg alloy by friction stir processing(FSP).Then,Mg alloy sample designed with different precipitated morphology ofβ-Mg_(17)Al_(12)phase was treated by microarc oxidation(MAO)in Na_(3)PO_(4)/Na2SiO3electrolyte.The characteristics and performance of the MAO coating was analyzed using scanning electron microscopy(SEM),energy dispersive spectrometer(EDS),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),contact angle meter,and potentiodynamic polarization.It was found that the coarseα-Mg grains in extruded AZ91D Mg alloy were refined by FSP,and theβ-Mg_(17)Al_(12)phase with reticular structure was broken and dispersed.The nano-ZrO_(2)particles were pinned at the grain boundary by FSP,which refined theα-Mg grain and promoted the precipitation ofβ-Mg_(17)Al_(12)phase in grains.It effectively inhibited the“cascade”phenomenon of microarcs,which induced the uniform distribution of discharge pores.The MAO coating on Zr-FSP sample had good wettability and corrosion resistance.However,TiO_(2)particles were hardly detected in the coating on TiFSP sample.

Effect of RE addition on solidification process and high-temperature strength of Al-12%Si-4%Cu-1.6%Mn heat-resistant alloy

The effect of RE addition on solidification process and high-temperature strength of Al-12%Si-4%Cu-1.6%Mn(in wt.%)heat-resistant alloy was investigated by microstructure observation and tensile test.A great number of fine needle-like RE-rich phases are observed in the alloys with RE addition. Solutionizing treatment does not change their morphologies and sizes, indicating that they have good thermal stability. The addition of RE totally alters the solidification process of eutectic CruAl2 phase, from network-like phase in the form of segregation at the final eutectic grain boundaries to discretely blocky phase growing on the hair-filamentous RE-rich needles. In the alloys with Ce addition, blocky CuAl2, particulate Al15Mn3Si2 and needle-like RE-rich needle phases grow together, but they did not occur in the alloy with only La addition. The addition of RE does not considerably improve the strength of the alloy at high temperatures. The formation of RE-rich phases also does not significantly alter the originating and propagating of micro-cracks in the alloy during tensile test.

Effect of pre-twinning and heat treatment on formability of AZX311 Mg alloy

In this study,the effects of pre-strain-induced tensile twins(TTWs)and controlled heat treatment on the formability behavior of AZX311 Mg alloy sheets were investigated.A 4%compressive strain was applied to pre-strain the sheets using the in-plane compression(IPC)technique along the rolling direction(RD)to introduce TTWs.The pre-strained(PS)samples were subsequently heat-treated at 250℃,350℃,and 400℃ independently for 1 hr,and are termed as PSA1,PSA2,and PSA3,respectively.Erichsen cupping tests were conducted to assess the formability of the sheet samples under different initial conditions.The results showed that the PS sample heat-treated at 250℃ for 1hr exhibited a decrease in the Erichsen index(IE)compared to the as-rolled sample,whereas PSA2 and PSA3 samples showed an increase in IE values.Microtexture analysis revealed that most of the TTWs generated through pre-twinning were stable at 250℃;however,the twin volume fraction reduced to 41%at 350℃ compared to the PS samples due to enhanced thermal activity at that temperature.Furthermore,PSA2 samples showed severe grain coarsening in some areas of the sample,and the fraction of such grains increased in the PSA3 samples.The stretch formability(IE value)of PSA2 samples showed a 32.3%increase compared to the as-rolled specimens.Additionally,the analysis of the deformed specimen at failure under the Erichsen test indicated that considerable detwinning occurs in the PS and PSA1 samples,whereas dislocation slip activity dominates in the PSA2 and PSA3 samples during stretch forming.Apart from detwinning and dislocation slip,deformation twins were also observed in all samples after the Erichsen test.Thus,this work highlights the importance of texture control and its underlying mechanisms via pre-twinning followed by heat treatment and their impact on the room temperature(RT)stretch formability of AZX311 Mg alloy sheets.

Microstructure and mechanical behavior of AXM Mg alloy systems—A review

Automobiles are the inevitable mode of transportation.However,increasing fuel prices and carbon dioxide emissions are posing a serious threat to automobile users and the environment.Thus,the development of new lightweight materials has been a key area of research.Magnesium-based commercial alloys(AZ and ZK series alloys)are the lightest among all structural metals.However,there is still a question about the replacement of Aluminum-based alloys due to HCP crystal structure.In this connection,Mg-Al-Ca-Mn(AXM)Mg alloy can be a choice as an alternative to the existing Mg-based commercial alloys for structural applications.It contains(Al,Mg)_(2)Ca,Al_(2)Ca,Mg_(2)Ca,and Al_(8)Mn_(5)as the secondary phases,contributing to the microstructural refinement and property enhancement.However,the formation of those precipitates depends on the amount of Al,Ca,and Mn,especially,the Ca/Al ratio.In addition,the secondary processes influence the grain refinement and property enhancement of texture modifications.Hence,this review article focuses on elaborating on the significance of the Ca/Al ratio for the precipitate formation,secondary process,and texture modifications.The co-segregation behavior of other micro-alloying elements like Cerium,Lanthanum,and Zinc in AXM Mg alloy systems has also been discussed for property enhancement.

Twinning aspects and their efficient roles in wrought Mg alloys:A comprehensive review

Twinning is widely recognized as an effective and cost-efficient method for controlling the microstructure and properties of wrought magnesium(Mg)alloys.Specifically,twins play a crucial role in initiating dynamic recrystallization(DRX),while twin regions experience rapid recrystallization during static recrystallization(SRX).The activation of twinning can lead to changes in lattice orientation,significantly impacting the final texture in Mg alloys.The active roles of twinning are influenced by various factors during the activation process,and the mobility of twin boundaries(TB)can be amplified by stress effects,dislocation interactions,and thermal effects.Conversely,annealing treatments that involve proper segregation or precipitation on TBs serve to stabilize them,restraining their motion.Events such as segregation may also alter the twinning propensity in Magnesium-rare earth(Mg-RE)alloys.While{10–11}contraction twins(CT)and{10–11}-{10–12}double twins(DT)can promote dynamic recrystallization(DRX),they also pose a risk as potential sources of voids and cracks.Additionally,understanding the nucleation and growth mechanisms of twinning is crucial,and these aspects are briefly reviewed in this article.Considering the factors mentioned above,this article summarizes the recent research progress in this field,shedding light on advancements in recent eras.

Maximizing the potential applications of plasma electrolytic oxidation coatings produced on Mg-based alloys in anti-corrosion,antibacterial,and photocatalytic targeting through harnessing the LDH/PEO dual structure

There is an increasing interest in the development of Mg alloys,both for industrial and biomedical applications,due to their favorable characteristics such as being lightweight and robust.However,the inadequate corrosion resistance and lack of antibacterial properties pose significant challenges in the industrial and biomedical applications,necessitating the implementation of advanced coating engineering techniques.Plasma electrolytic oxidation(PEO)has emerged as a preferred coating technique because of its distinctive properties and successful surface modification results.However,there is a continuous need for further enhancements to optimize the performance and functionalities of protective surface treatments.The integration of layered double hydroxide(LDH)into PEO coatings on Mg alloys presents a promising approach to bolstering protective properties.This thorough review delves into the latest developments in integrating LDH into PEO coatings for corrosion-related purposes.It particularly emphasizes the significant improvements in corrosion resistance,antibacterial effectiveness,and photocatalytic performance resulting from the incorporation of LDH into PEO coatings.The two key mechanisms that enhance the corrosion resistance of PEO coatings containing LDH are the anion exchangeability of the LDH structure and the pore-sealing effect.Moreover,the antibacterial activity of PEO coatings with LDH stemmed from the release of antibacterial agents stored within the LDH structure,alterations in pH levels,and the photothermal conversion property.Furthermore,by incorporating LDH into PEO coatings,new opportunities emerge for tackling environmental issues through boosted photocatalytic properties,especially in the realm of pollutant degradation.

Balanced strength and ductility by asymmetric gradient nanostructure in AZ91 Mg alloy

High-strength Mg alloys have historically suffered from a challenge in achieving good ductility.Here,we report an asymmetric gradient nanostructure design prepared by ultrasonic severe surface rolling(USSR)at room temperature.Unlike conventional gradient-nanostructured materials that employ a hard-soft-hard sandwich structure,this new design incorporates a combined gradient distribution of grain microstructure and nanoprecipitates throughout the entire sample along the thickness direction.The nanoprecipitates are identified as theβ-Mg_(17)Al_(12)phase and are primarily generated through In-situ pre-cipitation promoted by the USSR-induced high-density dislocations and temperature increment.Benefit-ing from this unique microstructure,an outstanding strength-ductility synergy is achieved,with a yield strength of 372.8 MPa,an ultimate tensile strength of 453.3 MPa,and an elongation of 11.5%.The en-hanced strength can be attributed to several mechanisms,including grain boundary strengthening,dislocation strengthening,precipitation strengthening,twin strengthening,and hetero-deformation induced(HDI)strengthening.The HDI hardening and activation of multiple deformation modes also contribute to good ductility.This work provides a promising and effective method for overcoming the longstanding strength-ductility trade-offdilemma in Mg alloys.

Structural,mechanical and electronic properties of precipitates in Mg−Zn alloys

To accelerate the development and design of magnesium(Mg)alloys,the structural and mechanical properties of important precipitates in Mg−Zn alloys were studied by experiments and density functional theory.The nano-indentation tests revealed that the hardness of the precipitates initially increased and then decreased with increasing Zn content,and was significantly higher than that of pure Mg and Zn.The calculation results revealed that the precipitates stability initially increased and then decreased with increasing Zn concentration.The bulk moduli of the precipitates increased,whereas their shear and Young’s moduli initially increased and then decreased with increasing Zn content.The decreasing order of ductility for these compounds is MgZn_(2)>Mg_(21)Zn_(25)>Mg_(2)Zn_(11)>Mg_(4)Zn_(7).The surface profiles of the compounds revealed that they are obvious anisotropy.Both the degree of covalency and bond length of covalent bonds initially increased and then decreased with increasing Zn content.

In situ TEM investigation of electron irradiation and aging-induced high-density nanoprecipitates in an Mg-10Gd-3Y-1Zn-0.5Zr alloy

In-situ electron irradiation and aging are applied to introduce high-density precipitates in an Mg-10Gd-3Y-1Zn-0.5Zr(GWZ1031K,wt.%)alloy to improve the hardness.The results show that the hardness of the Mg alloy after irradiation for 10 h and aging for 9 h at 250℃ is 1.64 GPa,which is approximately 64% higher than that of the samples before being treated.It is mainly attributed to γ'precipitates on the basal plane after irradiation and the high-density nanoscale β'precipitates on the prismatic plane after aging,which should be closely related to the irradiation-induced homogenous clusters.The latter plays a key role in precipitation hardening.This result paves a way to improve the mechanical properties of metallic materials by tailoring the precipitation through irradiation and aging.

Development of anti-corrosive coating on AZ31 Mg alloy modified by MOF/LDH/PEO hybrids

The self-assembly of hybrid inorganic-organic materials on stationary platforms plays a critical role in improving their structural stability and wide usability.In this work,a novel two-step hydrothermal approach is proposed for synthesizing stable and advanced hybrid coatings on metal-oxide platforms through the surface modification of layered double hydroxide(LDH)films using novel metal-organic frameworks(MOFs).Initially,Mg-Al LDH nanocontainers,grown on a magnesium oxide layer produced through plasma electrolytic oxidation(PEO)of AZ31 Mg alloy substrate,were intercalated with cobalt via an oxidation route,providing the metallic coordination center for the MOF formation.In the subsequent step,a pioneering technique is introduced,utilizing tryptophan as the organic linker for the first time at a pH of 10.The self-assembly of cobalt-tryptophan complex,driven by the strong bonding between electrophilic sites of monomers and nucleophilic sites,facilitated the formation of a MOF network having a cloud-like structure on the surface of MgAl LDH's film.The resulting MOF-LDH encapsulation containers demonstrate exceptional electrochemical stability when exposed to a 3.5 wt.%NaCl solution,surpassing the performance of PEO and pure LDH coatings.This enhanced stability is attributed to the development of a dense top layer and a stable composition within the self-assembled MOF,effectively sealing flaws and preventing the infiltration of corrosive ions into the underlying metallic substrate.The formation mechanism of MOFs on LDH galleries is investigated using density functional theory calculations.

Microstructural evolution and mechanical properties of AZ31 Mg alloy fabricated by a novel bifurcation-equal channel angular pressing

In this work,a novel type of short-process deformation technology of Mg alloys,bifurcation-equal channel angular pressing(B-ECAP),was proposed to refine grain and improve the basal texture.The cylindrical billets were first compressed into the die cavity,then sequentially flowed downward through a 90°corner and two 120°shear steps.The total strain of B-ECAP process could reach 3.924 in a single pass.The results of microstructure observation showed that DRX occurred at upsetting process in the die cavity and completed at position D.The grains were refined to 6.3μm at being extruded at 300℃ and grew obviously with the extrusion temperature increase.The shear tress induced by 900 corner and two 120°shear steps resulted in the basal poles of most grains tilted to extrusion direction(ED)by±25°.Compared with the original billets,the extruded sheets exhibited higher yield strengths(YS),which was mainly attributed to the grain refinement.The higher Schmid factor caused by ED-tilt texture resulted in a fracture elongation(FE)more than that of the original bar in ED,while was equivalent to that in transverse direction(TD).As the extrusion temperature increased,the variation of UTS and YS in ED and TD decreased gradually without ductility obviously decrease.

Antibacterial HA-coatings on bioresorbable Mg alloy

In this study,a calcium-phosphate coating was formed on a Mg-Mn-Ce alloy by the plasma electrolytic oxidation(PEO).The antibiotic vancomycin,widely used in the treatment of infections caused by Staphylococcus aureus(S.aureus),was impregnated into the coating.Samples with vancomycin showed high bactericidal activity against S.aureus.The mechanical and electrochemical properties of the formed coatings were studied,as well as in vitro cytotoxicity tests and in vivo tests on mature male rats were performed.According to SEM,EDS,XRD and XPS data,coatings had a developed morphology and contained hydroxyapatite,which indicates high biocompatibility.The analysis of roughness of coatings without and with vancomycin did not reveal any differences,confirming the high roughness of the samples.During electrochemical tests,an increase in corrosion resistance by more than two times after the application of PEO coatings was revealed.According to the results of an in vivo study,after 28 days of the implantation of samples with calcium phosphate PEO coating and vancomycin,no signs of inflammation were observed,while an inflammatory reaction developed in the area of implantation of bare alloy,followed by encapsulation.Antibiotic release tests from the coatings show a sharp decrease in the concentration of the released antibiotic on day 7 and then a gradual decrease until day 28.Throughout the experiment,no significant deviations in the condition and behavior of the animals were observed;clinical tests did not reveal a systemic toxic reaction.

Precipitation of multi-type nano-quasicrystals in a Mg-Zn-Y alloy

Mg-6Zn-1Y(at.%)ribbons with strengthening precipitates of multi-type nanoquasicrystals were prepared by melt-spinning followed by aging treatments.Microstructural evolution of the rapidly solidified ribbons during isothermal aging was comprehensively studied using various electron microscopy techniques.Two new kinds of decagonal quasicrystals were formed in aged ribbons,in addition to precipitation of nanometer icosahedral quasicrystals.Atomic-resolution observations reveal that both decagonal quasicrystals can be modeled by quasiperiodic tiling with decagonal clusters of 2.5 nm in diameter,but overlap of neighboring clusters in both decagonal quasicrystals is different from the Gummelt model observed in other quasicrystals.A shell composed of complex Laves Mg-Zn domains was formed surrounding each decagonal quasicrystal precipitate upon prolonged aging.In addition,all kinds of nanoprecipitates exhibit excellent structure and size stability at 573 K.Our findings may have implications for not only fundamental studies about quasicrystals,but also microstructural manipulation of high-performance Mg alloys.