Bio-magnesium(Mg)alloys exhibit excellent biocompatibility and biodegradability,making them highly promising for implant applications.However,their limited strength-ductility balance remains a critical challenge restr...Bio-magnesium(Mg)alloys exhibit excellent biocompatibility and biodegradability,making them highly promising for implant applications.However,their limited strength-ductility balance remains a critical challenge restricting widespread use.In this study,ultra-fine-grained and homogeneous Mg alloys were fabricated using double-sided friction stir processing(DS-FSP)with liquid CO_(2) rapid cooling,leading to a significant enhancement in the strength-ductility synergy of the stirred zone.The results demonstrate that DS-FSP samples exhibit simultaneous improvements in ultimate tensile strength(UTS)and elongation,reaching 334.1±15 MPa and 28.2±7.3%,respectively.Compared to the non-uniform fine-grained microstructure obtained through single-sided friction stir processing,DS-FSP generates a uniform ultra-fine-grained structure,fundamentally altering the fracture behavior and mechanisms of Mg alloys.The DS-FSP samples exhibit irregular fracture patterns due to variations in basal slip system activation among different grains.In contrast,single-sided friction stir processing samples,characterized by a fine-grained yet heterogeneous microstructure,display flat shear fractures dominated by high-density dislocation initiation induced by twin formation,with fracture propagation dictated by the non-uniform texture.By achieving an ultra-fine grain size and homogeneous texture,DS-FSP effectively modifies the fracture mechanisms,thereby enhancing the strength-ductility balance of bio-magnesium alloys.展开更多
To investigate the instability mechanisms of heterogeneous geological structures in goaf area roofs,three-point bending tests(TPBT)and numerical simulations are performed on composite coal-rock(CCR).Acoustic emission(...To investigate the instability mechanisms of heterogeneous geological structures in goaf area roofs,three-point bending tests(TPBT)and numerical simulations are performed on composite coal-rock(CCR).Acoustic emission(AE)monitoring is employed to analyze key parameters,establishing a multiparameter quantitative system for CCR fracture processes.The impact of lithological homogeneity on fracture evolution and energy migration is examined.Results show that CCR exhibits a three-stage mechanical response:weak contact,strong contact,and post-peak stages,each with distinct crack evolution patterns.A positive correlation is found between lithological homogeneity and tensile crack proportion.No significant correlation is observed between AE average frequency(AF)and AE counts across different lithological CCR;however,peak frequency(PF)displays clear lithology-dependent characteristics.The regulatory effect of the rock homogeneity coefficient(φ)on crack deriva tion mechanisms is quantfied,yielding mathematical relationships between fracture strength(f),crack propagation path angle(β),crack fractal dimension(D),andφ.The study highlights how different fracture modes alter energy migration pathways,confirming the coupling effect of grain distribution on mechanical response and crack propagation,and the influence of parameterφon critical energy release zones.These findings offer new insights into CCR failure mechanisms for mining safety.展开更多
The nonuniform microstructure of magnesium alloy rolled sheets tends to influence their plastic deformation capacity.This study employed multi-pass restricted rolling to successfully prepare AZ31 magnesium alloy rolle...The nonuniform microstructure of magnesium alloy rolled sheets tends to influence their plastic deformation capacity.This study employed multi-pass restricted rolling to successfully prepare AZ31 magnesium alloy rolled sheets with a uniform microstructure,enhancing their mechanical properties.Quasi-in-situ tensile EBSD was used to investigate the effect of microstructure uniformity on the plastic deformation and fracture behavior of magnesium alloy.The results demonstrate that the nonuniformity of the magnesium alloy microstructure intensifies the strain asynchrony between adjacent grains,leading to relative misalignment and crack formation.Fine grains cannot coordinate the strain within their adjacent coarse grains,resulting in ledge formation at their common grain boundaries.Moreover,low-angle grain boundaries(LAGB)influence fracture behavior,rendering fine grains penetrated by LAGB more susceptible to becoming strain concentration areas that promote intergranular fracture and even transgranular fracture.展开更多
Lumbar degeneration leads to changes in geometry and density distribution of vertebrae,which could further influence the mechanical property and behavior.This study aimed to quantitatively describe the variations in s...Lumbar degeneration leads to changes in geometry and density distribution of vertebrae,which could further influence the mechanical property and behavior.This study aimed to quantitatively describe the variations in shape and density distribution for degenerated vertebrae by statistical models,and utilized the specific statistical shape model(SSM)/statistical appearance model(SAM)modes to assess compressive strength and fracture behavior.Highly detailed SSM and SAM were developed based on the 75 L1 vertebrae of elderly men,and their variations in shape and density distribution were quantified with principal component(PC)modes.All vertebrae were classified into mild(n=22),moderate(n=29),and severe(n=24)groups according to the overall degree of degeneration.Quantitative computed tomography-based finite element analysis was used to calculate compressive strength for each L1 vertebra,and the associations between compressive strength and PC modes were evaluated by multivariable linear regression(MLR).Moreover,the distributions of equivalent plastic strain(PEEQ)for the vertebrae assigned with the first modes of SSM and SAM at mean±3SD were investigated.The Leave-One-Out analysis showed that our SSM and SAM had good performance,with mean absolute errors of 0.335±0.084 mm and 64.610±26.620 mg/cm3,respectively.A reasonable accuracy of bone strength prediction was achieved by using four PC modes(SSM 1,SAM 1,SAM 4,and SAM 5)to construct the MLR model.Furthermore,the PEEQ values were more sensitive to degeneration-related variations of density distribution than those of morphology.The density variations may change the deformity type(compression deformity or wedge deformity),which further affects the fracture pattern.Statistical models can identify the morphology and density variations in degenerative vertebrae,and the SSM/SAM modes could be used to assess compressive strength and fracture behavior.The above findings have implications for assisting clinicians in pathological diagnosis,fracture risk assessment,implant design,and preoperative planning.展开更多
Dual-phase heterogeneous structures confer eutectic high-entropy alloy(EHEA)with excellent strength-ductility synergy under quasi-static tensile loading.However,it is questionable whether the EHEAs pos-sess equally go...Dual-phase heterogeneous structures confer eutectic high-entropy alloy(EHEA)with excellent strength-ductility synergy under quasi-static tensile loading.However,it is questionable whether the EHEAs pos-sess equally good impact toughness because the phase interfaces are vulnerable to crack initiation.This work aimed to study the Charpy impact toughness and fracture behavior of AlCoCrFeNi_(2.1) EHEA.The results indicate that while maintaining high tensile strength and ductility,the AlCoCrFeNi_(2.1) EHEA also shows a satisfactory impact toughness of 25.86 J/cm^(2),superior to most other dual-phase alloys like TC4 titanium alloy or DP steel.Fractography analysis reveals characteristic regions of the fracture surface,which suggests energy absorption mechanisms primarily through ductile dimples,flat cleavage facets,secondary cracks,and microvoids,corresponding to a ductile-brittle mixed fracture mode.Detailed obser-vations of the deformed microstructure through TEM and EBSD demonstrate that FCC(L1_(2))and BCC(B2)phases underwent concurrent tearing along their phase boundaries,indicating a crucial influence of phase boundaries over crack initiation and propagation.The FCC(L1_(2))phase bore almost all plastic deformation of the sample through dislocation slip,whereas the BCC(B2)phase underwent a rapid shearing but almost no dislocation slip.Crack initiation under impact loading typically starts at the FCC(L1_(2))/BCC(B2)inter-face before propagating through the BCC(B2)phase.Additionally,this work further examines the effect of sample size and notch shape on the impact toughness of AlCoCrFeNi_(2.1) EHEA.A comparative analysis of the mechanical behavior under static and impact loading was also conducted,highlighting differences and connections in stress distribution and fracture surface morphology.The study offers valuable insights into the mechanical response and fracture behavior of AlCoCrFeNi_(2.1) EHEA under impact loading,provid-ing crucial information for its potential industrial applications.展开更多
This work used the in-situ synthesis of molten-state nitride ceramic phase-reinforced Ni-based alloy coat-ings,aiming to improve the phase-interface bonding through the interdependent co-solidification be-tween molten...This work used the in-situ synthesis of molten-state nitride ceramic phase-reinforced Ni-based alloy coat-ings,aiming to improve the phase-interface bonding through the interdependent co-solidification be-tween molten droplets.The XRD was used to analyze the physical phases of the composite coatings.The microstructure and phase-interface structure were characterized in detail by combining SEM,TEM,HRTEM,FFT,and SAED techniques.Microhardness tester and microforce microhardness tester were em-ployed to measure the surface hardness and elastic modulus of the composite coatings.The fracture be-havior of the composite coatings was characterized by observing the fracture morphology of the coatings using SEM combined with the EDS technique.It was found that the formation mechanisms of inter-facial misfit dislocation assistance,lattice distortion,aggregation of stacking faults,and specific growth orientation between theγ-Ni matrix phase and each ceramic phase in NiCrBSi-TiCrN composite coat-ings improved the lattice matching between the two-phase interface,which resulted in the formation of atomically corresponding coherent lattice relations and stepped interfacial semi-coherent lattice relations,and enhanced the degree of phase-interface bonding.On this basis,the composite coatings with high Cr content further inhibited the expansion of interphase penetration cracks due to the existence of Cr-rich zones at the phase interface,thus exhibiting high fracture toughness.This work provides new opinions on the improvement of phase-interface bonding and composition design of Ni-based composite coatings.展开更多
Shape memory alloys(SMAs)and shape memory ceramics(SMCs)exhibit high recovery ability due to the martensitic transformation,which complicates the fracture mechanism of SMAs and SMCs.The phase field method,as a powerfu...Shape memory alloys(SMAs)and shape memory ceramics(SMCs)exhibit high recovery ability due to the martensitic transformation,which complicates the fracture mechanism of SMAs and SMCs.The phase field method,as a powerful numerical simulation tool,can efficiently resolve the microstructural evolution,multi-field coupling effects,and fracture behavior of SMAs and SMCs.This review begins by presenting the fundamental theoretical framework of the fracture phase field method as applied to SMAs and SMCs,covering key aspects such as the phase field modeling of martensitic transformation and brittle fracture.Subsequently,it systematically examines the phase field simulations of fracture behaviors in SMAs and SMCs,with particular emphasis on how crystallographic orientation,grain size,and grain boundary properties influence the crack propagation.Additionally,the interplay between martensite transformation and fracture mechanisms is analyzed to provide deeper insights into the material responses under mechanical loading.Finally,the review explores future prospects and emerging trends in phase field simulations of SMA and SMC fracture behavior,along with potential advancements in the fracture phase field method itself,including multi-physics coupling and enhanced computational efficiency for large-scale simulations.展开更多
In this work,AZ31B extruded sheets with mixed-grain microstructures were prepared through extrusion.Samples of mixed-grain microstructure with different morphologies were selected from the AZ31B extruded sheets(referr...In this work,AZ31B extruded sheets with mixed-grain microstructures were prepared through extrusion.Samples of mixed-grain microstructure with different morphologies were selected from the AZ31B extruded sheets(referred to as M1 and M2 samples,respectively).The creep tests were performed on these samples at the temperature range of 150-200℃,and the stress level range of 50-100 MPa.The creep properties and fracture behavior of AZ31 extruded sheets with mixed-grain microstructures were studied.Results showed that the creep properties of the M2 sample always outperformed that of the M1 sample and M1 and M2 samples’creep was dominated by dislocation movement.The creep rate of M2 samples(1.5×10^(-7)±1.1×10^(-10) s^(-1))is an order of magnitude lower than that of M1 samples(4.8×10^(-6)±8.1×10^(-10) s^(-1))at 200℃under 50 MPa The high activity of basal slip and softening mechanism in the M1 sample significantly accelerated creep,resulting in a relatively high creep rate.Moreover,the stress concentration within the M1 sample caused by deformation incompatibility,increased the initiation and propagation of voids,ultimately leading to fracture and poorer creep performance.However,the numerous<10µm fine grains surrounding deformed coarse grains in the M2 sample facilitated better coordination of deformation through dislocation slip,effectively slowing down the initiation of voids during the creep process.Meanwhile,the strain was uniformly distributed within each grain,mitigating stress concentration,inhibiting voids propagation,and contributing to the superior creep resistance of the M2 sample.展开更多
In dry storage,spent fuel is typically stored in casks constructed from neutron absorbing materials(NAMs).The(B_(4)C+Al_(2)O_(3))/Al composite,which incorporates in-situ amorphous Al_(2)O_(3)(am-Al_(2)O_(3))formed on ...In dry storage,spent fuel is typically stored in casks constructed from neutron absorbing materials(NAMs).The(B_(4)C+Al_(2)O_(3))/Al composite,which incorporates in-situ amorphous Al_(2)O_(3)(am-Al_(2)O_(3))formed on fine aluminum powder as a reinforcing phase,can serve as an integrated structural and functional NAM for dry storage applications.Welding is crucial in the fabrication of these casks.In this study,friction stir welding was performed on(B_(4)C+Al_(2)O_(3))/Al composite sheets at a welding speed of 50 mm/min and rotation rates ranging from 500 to 1000 r/min.The microstructure of the weld joints was analyzed,and the intrinsic relationship between fracture behavior and microstructure was elucidated.Results showed that defect-free joints were achieved at rotation rates of 500 and 750 r/min,while tunnel defects were observed at 1000 r/min.The ultimate tensile strength of the joint welded at 500 r/min was 205.7 MPa,with a strength efficiency of 82%.Microstructural analysis revealed that the grains within the nugget zones(NZs)coarsened and the Al_(2)O_(3)network was disrupted due to the welding thermo-mechanical effect,resulting in softening within the NZs.Fracture locations for all three joints were consistently observed at the NZ boundary on the advancing side(AS).Finite element simulations confirmed that cracks propagated along the NZ boundary on the AS,where stress concentration occurred during tensile testing.展开更多
In this paper,the effect of the Si content on microstructure evolution,mechanical properties,and fracture behavior of the Al-xSi/AZ91D bimetallic composites prepared by compound casting was investigated systematically...In this paper,the effect of the Si content on microstructure evolution,mechanical properties,and fracture behavior of the Al-xSi/AZ91D bimetallic composites prepared by compound casting was investigated systematically.The obtained results showed that all the Al-xSi/AZ91D bimetallic composites had a metallurgical reaction layer(MRL),whose thickness increased with increasing Si content for the hypoeutectic Al-Si/AZ91D composites,while the hypereutectic Al-Si/AZ91D composites were opposite.The MRL included eutectic layer(E layer),intermetallic compound layer(IMC layer)and transition region layer(T layer).In the IMC layer,the hypereutectic Al-Si/AZ91D composites contained some Si solid solution and flocculent Mg_(2)Si+Al-Mg IMCs phases not presented in the hypoeutectic Al-Si/AZ91D composites.Besides,increasing Si content,the thickness proportion of the T layer increased,forming an inconsistent preferred orientation of the MRL.The shear strengths of the Al-xSi/AZ91D bimetallic composites enhanced with increasing Si content,and the Al-15Si/AZ91D composite obtained a maximum shear strength of 58.6 MPa,which was 73.4% higher than the Al-6Si/AZ91D composite.The fractures of the Al-xSi/AZ91D bimetallic composites transformed from the T layer into the E layer with the increase of the Si content.The improvement of the shear strength of the Al-xSi/AZ91D bimetallic composites was attributed to the synergistic action of the Mg_(2)Si particle reinforcement,the reduction of oxidizing inclusions and the ratio of Al-Mg IMCs as well as the orientation change of the MRL.展开更多
The mechanical properties and fracture morphologies of Cu/Nb multilayer composites under electric-assisted tension(EAT)were investigated.Results show that the generated Joule-heat leads to obvious stress softening wit...The mechanical properties and fracture morphologies of Cu/Nb multilayer composites under electric-assisted tension(EAT)were investigated.Results show that the generated Joule-heat leads to obvious stress softening with the increase in current density.However,the elongation decreases,which is closely related to the characteristic fracture behavior of Cu/Nb multilayer composites during EAT.The fracture pattern is gradually transformed from ductile fracture to melt fracture with the increase in current density.展开更多
The lamellar hydrates of CAC were designed with the introduction of nano CaCO_(3)or Mg-Al hydrotalcite(M-A-H),and the effects on the green strength,pore structures,and high-temperature fracture behavior of alumina-spi...The lamellar hydrates of CAC were designed with the introduction of nano CaCO_(3)or Mg-Al hydrotalcite(M-A-H),and the effects on the green strength,pore structures,and high-temperature fracture behavior of alumina-spinel castables were investigated.The results show that nano CaCO_(3)or M-A-H stimulates rapidly the hydration of CAC and the formation of lamellar C_(4)AcH_(11)or coexistence of C_(2)AH_(8)and C_(4)AcH_(11)at 25℃.The formation of lamellar hydrates can contribute to a more complicated pore structure,especially in the range of 400-2000 nm.Meanwhile,the incorporation of well-distributed CaO or MgO sources from nano CaCO_(3)or M-A-H also regulates the distribution of CA_(6)and spinel(pre-formed and in-situ).Consequently,the optimized microstructure and complicated pore structure can induce the deflection and bridging of cracks,thus facilitating the consumption of fracture energy and enhancing the resistance to thermal stress damage.展开更多
An aluminum-based in-situ composites reinforced with Mg2Si and Si particles were produced by centrifugal casting A1-20Si-5Mg alloy. The microstructure of the composites was examined, and the effects of temperature on ...An aluminum-based in-situ composites reinforced with Mg2Si and Si particles were produced by centrifugal casting A1-20Si-5Mg alloy. The microstructure of the composites was examined, and the effects of temperature on fracture behavior of the composite were investigated. The results show that the average fraction of primary Si and Mg2Si particles in the composites is as high as 38%, and ultimate tensile strengths （UTS） of the composites first increase then decrease with the increase of test temperature. Microstructures of broken specimens show that both the particle fracture and the interface debonding affect the fracture behavior of the composites, and the interface debonding becomes the dominant fracture mechanism with increasing test temperature. Comparative results indicate that rich particles in the composites and excellent interface strength play great roles in enhancing tensile property by preventing the movement of dislocations.展开更多
The effects of plastic deformation on precipitation behavior and tensile fracture behavior of Mg-10Gd-3Y-0.6Zr alloy were investigated.The results indicate that more precipitation cores can be provided by the crystal ...The effects of plastic deformation on precipitation behavior and tensile fracture behavior of Mg-10Gd-3Y-0.6Zr alloy were investigated.The results indicate that more precipitation cores can be provided by the crystal defects caused by the plastic deformation,as well as increasing the amount of β＇ phases,and the formation of precipitations at grain boundaries and interfaces between the twins and matrix.Because of an increase in precipitations,the dislocation slipping during deformation process is effectively hindered and the matrix is strengthened,especially for the 2% deformed alloy which can achieve a good combination of strength and ductility.With increasing the plastic deformation,the microcracks occur at the interface between grain boundary precipitations and matrix,and then propagate intergranularly.When intergranular fracture combines with the formation of smoothing facets on the fracture surface,the tensile properties decrease.展开更多
2219-T8 aluminum alloys were butt welded by the double-pass tungsten inert gas （TIG） arc welding process. The transverse tensile test of the joint showed that the fracture mainly occurred in the partially melted zo...2219-T8 aluminum alloys were butt welded by the double-pass tungsten inert gas （TIG） arc welding process. The transverse tensile test of the joint showed that the fracture mainly occurred in the partially melted zone （PMZ）. Effects of the PMZ on the fracture behavior were systematically studied. Continuous intergranular eutectics were observed in the PMZ close to the fusion line. Away from the fusion line, the intergranular eutectics in the PMZ became discontinuous. The fracture morphology and the microhardness distribution of the joint showed that the PMZ was gradient material with different mechanical properties, which strongly affected the fracture process. It was observed that the crack initiated in the PMZ near the front weld toe, and propagated in the PMZ away from the fusion line. Then, the crack tip was blunt when it propagated into the PMZ with higher plasticity. Finally, the rest part of the joint was shear fractured.展开更多
The strength and fatigue fracture behavior of A1-Zn-Mg-Cu-Zr（-Sn） alloys were studied by performing tensile tests and fatigue crack propagation （FCP） tests. The microstructures of the experimental alloys were furt...The strength and fatigue fracture behavior of A1-Zn-Mg-Cu-Zr（-Sn） alloys were studied by performing tensile tests and fatigue crack propagation （FCP） tests. The microstructures of the experimental alloys were further analyzed using optical microscopy （OM）, scanning electron microscopy （SEM）, and transmission electron microscopy （TEM）; phase analysis of these alloys was conducted with an X-ray diffraction （XRD）. The results show that when Sn is included, growth of the recrystallization grains in the solution-treated A1-Zn-Mg-Cu-Zr alloy is obstructed, the precipitation-free zone （PFZ） of the overaged A1-Zn-Mg-Cu-Zr-Sn alloy becomes narrow, and the grain boundary precipitates are smaller. Consequently, the FCP resistance is higher. In addition, the overaged Sn-containing alloy has considerably higher tensile strength than the alloy without Sn.展开更多
The as-cast ingot of equiatomic nickel-titanium shape memory alloy （NiTi SMA） was prepared by vacuum consumable arc melting. The tensile tests and the compressive tests with respect to as-cast NiTi SMA were performe...The as-cast ingot of equiatomic nickel-titanium shape memory alloy （NiTi SMA） was prepared by vacuum consumable arc melting. The tensile tests and the compressive tests with respect to as-cast NiTi SMA were performed to study its mechanical properties of fracture. The microanalysis of as-cast NiTi SMA as well as its fractured samples was performed so as to better understand microstructure evolution and fracture behavior of NiTi SMA. Under tensile loading, the as-cast NiTi SMA shows higher plasticity and is characterized by ductile fracture at 750℃, but it demonstrates poorer plasticity and is characterized by cleavage fracture as well as transcrystalline fracture at room temperature and -100 ℃. Under compressive loading at -100 ~C, the as-cast NiTi SMA is characterized by shear fracture where the normal to the shearing fracture surface inclines about 45° to the compressive axis, and belongs to cleavage fracture where the cracks exoand via transcrvstalline fracture.展开更多
Using an optical microscope and scanning electron microscope (SEM), the variation of eutectic Si morphology of Al-Si alloy in solution treatment was observed to study its influence on mechanical properties and fractur...Using an optical microscope and scanning electron microscope (SEM), the variation of eutectic Si morphology of Al-Si alloy in solution treatment was observed to study its influence on mechanical properties and fracture behavior. The results show that eutectic Si undergoes stubbing, necking, fragmentation, and growth in the initial stage (250 min); in the middle solution stage (250 to 400 min), the eutectic Si morphology has no significant change, only the degree of spheroidizing becomes higher; after 600 min, the growth of eutectic Si is a coarsening process controlled by diffusion and follows the Liftshitz-Slyozov-Wangner (LSW) model, and the eutectic Si morphology deteriorates due to the occurrence of facets and lap. Based on the quantitative measure and regression analysis, the eutectic Si morphology has a remarkable influence on mechanical properties and fracture behavior.展开更多
The fracture behavior of a permanent mould casting Mg-8.57Gd-3.72Y-0.54Zr(mass fraction,%)(GW94) alloy was investigated under different thermal conditions,including as-cast,solution-treated,peak-aged,and over-aged sta...The fracture behavior of a permanent mould casting Mg-8.57Gd-3.72Y-0.54Zr(mass fraction,%)(GW94) alloy was investigated under different thermal conditions,including as-cast,solution-treated,peak-aged,and over-aged states.Scanning electron microscopy(SEM) and optical microscopy(OM) were employed to examine the crack nucleation and fracture model.The results indicate that the GW94 alloy shows different behaviors of crack initiation and fracture under different thermal conditions. During tensile test at room temperature,the fracture model of the as-cast GW94 alloy is quasi-cleavage,while that of the solution-treated alloy is transgranular cleavage.It is a mixed pattern of transgranular and intergranular fracture for both the aged conditions.Large cavities formed at grain boundaries are observed in the peak-aged sample tested at 300℃,corresponding to the intergranular fracture.Localized plastic deformation at grain boundaries is also observed and corresponds to the high elongation at 300℃.展开更多
In the present work, Zn-（0-1）Mg（wt%） alloys were prepared by casting and indirect extrusion at 200 and300 ℃, respectively. With Mg addition, both the size and amount of second phase Mg2Zn（11） increased, and the...In the present work, Zn-（0-1）Mg（wt%） alloys were prepared by casting and indirect extrusion at 200 and300 ℃, respectively. With Mg addition, both the size and amount of second phase Mg2Zn（11） increased, and the equiaxed grains were significantly refined. The extrusion temperature had little influence on Mg2Zn（11）, but the grains were refined at low extrusion temperature. For the alloys extruded at 200 ℃, as Mg content increased, the tensile yield strength（TYS）increased from 64 MPa for pure Zn to 262 MPa for Zn-1Mg; the elongation increased from 14.3% for pure Zn to 25% for Zn-0.02Mg and then decreased to 5% for Zn-1Mg. For the alloys extruded at 300 ℃, as Mg content increased, the TYS increased from 67 MPa for pure Zn to 252 MPa for Zn-1Mg, while the elongation decreased from 11.7% to 2%. The alloy extruded at 200 ℃ exhibited higher TYS and elongation than the corresponding alloy extruded at 300 ℃. The combination of grain refinement and second phase Mg2Zn（11） contributed to the improvement in the TYS, and the grain refinement played a major role in strengthening alloy. Zn-0.02Mg and Zn-0.05Mg alloys extruded at 200 ℃ show a mixture of cleavage and ductile fracture corresponding to higher elongation, while the other alloys show cleavage fracture.展开更多
基金financial support from the National Key Research and Development Program of China(2021YFC2400703)Zhengzhou City Major Special Project for Collaborative InnovationChina Scholarship Council。
文摘Bio-magnesium(Mg)alloys exhibit excellent biocompatibility and biodegradability,making them highly promising for implant applications.However,their limited strength-ductility balance remains a critical challenge restricting widespread use.In this study,ultra-fine-grained and homogeneous Mg alloys were fabricated using double-sided friction stir processing(DS-FSP)with liquid CO_(2) rapid cooling,leading to a significant enhancement in the strength-ductility synergy of the stirred zone.The results demonstrate that DS-FSP samples exhibit simultaneous improvements in ultimate tensile strength(UTS)and elongation,reaching 334.1±15 MPa and 28.2±7.3%,respectively.Compared to the non-uniform fine-grained microstructure obtained through single-sided friction stir processing,DS-FSP generates a uniform ultra-fine-grained structure,fundamentally altering the fracture behavior and mechanisms of Mg alloys.The DS-FSP samples exhibit irregular fracture patterns due to variations in basal slip system activation among different grains.In contrast,single-sided friction stir processing samples,characterized by a fine-grained yet heterogeneous microstructure,display flat shear fractures dominated by high-density dislocation initiation induced by twin formation,with fracture propagation dictated by the non-uniform texture.By achieving an ultra-fine grain size and homogeneous texture,DS-FSP effectively modifies the fracture mechanisms,thereby enhancing the strength-ductility balance of bio-magnesium alloys.
基金support from the National Key Research and Development Plan Project(No.2022YFC3004700)the National Natural Science Foundation of China(No.52374241)+1 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX24_2924)Graduate Innovation Program of China University of Mining and Technology(No.2024WLKXJ151).
文摘To investigate the instability mechanisms of heterogeneous geological structures in goaf area roofs,three-point bending tests(TPBT)and numerical simulations are performed on composite coal-rock(CCR).Acoustic emission(AE)monitoring is employed to analyze key parameters,establishing a multiparameter quantitative system for CCR fracture processes.The impact of lithological homogeneity on fracture evolution and energy migration is examined.Results show that CCR exhibits a three-stage mechanical response:weak contact,strong contact,and post-peak stages,each with distinct crack evolution patterns.A positive correlation is found between lithological homogeneity and tensile crack proportion.No significant correlation is observed between AE average frequency(AF)and AE counts across different lithological CCR;however,peak frequency(PF)displays clear lithology-dependent characteristics.The regulatory effect of the rock homogeneity coefficient(φ)on crack deriva tion mechanisms is quantfied,yielding mathematical relationships between fracture strength(f),crack propagation path angle(β),crack fractal dimension(D),andφ.The study highlights how different fracture modes alter energy migration pathways,confirming the coupling effect of grain distribution on mechanical response and crack propagation,and the influence of parameterφon critical energy release zones.These findings offer new insights into CCR failure mechanisms for mining safety.
基金supported by the National Natural Science Foundation of China(No.U1810208)Shanxi Province Science and Technology Major Projects,China(No.2018110100)。
文摘The nonuniform microstructure of magnesium alloy rolled sheets tends to influence their plastic deformation capacity.This study employed multi-pass restricted rolling to successfully prepare AZ31 magnesium alloy rolled sheets with a uniform microstructure,enhancing their mechanical properties.Quasi-in-situ tensile EBSD was used to investigate the effect of microstructure uniformity on the plastic deformation and fracture behavior of magnesium alloy.The results demonstrate that the nonuniformity of the magnesium alloy microstructure intensifies the strain asynchrony between adjacent grains,leading to relative misalignment and crack formation.Fine grains cannot coordinate the strain within their adjacent coarse grains,resulting in ledge formation at their common grain boundaries.Moreover,low-angle grain boundaries(LAGB)influence fracture behavior,rendering fine grains penetrated by LAGB more susceptible to becoming strain concentration areas that promote intergranular fracture and even transgranular fracture.
基金supported by the National Natural Science Foundation of China(Grant No.12272029).
文摘Lumbar degeneration leads to changes in geometry and density distribution of vertebrae,which could further influence the mechanical property and behavior.This study aimed to quantitatively describe the variations in shape and density distribution for degenerated vertebrae by statistical models,and utilized the specific statistical shape model(SSM)/statistical appearance model(SAM)modes to assess compressive strength and fracture behavior.Highly detailed SSM and SAM were developed based on the 75 L1 vertebrae of elderly men,and their variations in shape and density distribution were quantified with principal component(PC)modes.All vertebrae were classified into mild(n=22),moderate(n=29),and severe(n=24)groups according to the overall degree of degeneration.Quantitative computed tomography-based finite element analysis was used to calculate compressive strength for each L1 vertebra,and the associations between compressive strength and PC modes were evaluated by multivariable linear regression(MLR).Moreover,the distributions of equivalent plastic strain(PEEQ)for the vertebrae assigned with the first modes of SSM and SAM at mean±3SD were investigated.The Leave-One-Out analysis showed that our SSM and SAM had good performance,with mean absolute errors of 0.335±0.084 mm and 64.610±26.620 mg/cm3,respectively.A reasonable accuracy of bone strength prediction was achieved by using four PC modes(SSM 1,SAM 1,SAM 4,and SAM 5)to construct the MLR model.Furthermore,the PEEQ values were more sensitive to degeneration-related variations of density distribution than those of morphology.The density variations may change the deformity type(compression deformity or wedge deformity),which further affects the fracture pattern.Statistical models can identify the morphology and density variations in degenerative vertebrae,and the SSM/SAM modes could be used to assess compressive strength and fracture behavior.The above findings have implications for assisting clinicians in pathological diagnosis,fracture risk assessment,implant design,and preoperative planning.
基金financially supported by the Natural Science Spe-cial(Special Post)Research Foundation of Guizhou University(No.2023-46)the Youth Science and Technology Talent Development Program of Guizhou(No.QKJ[2024]24)the National Natural Science Foundation of China(Nos.52274260,52074096,and 52164017).
文摘Dual-phase heterogeneous structures confer eutectic high-entropy alloy(EHEA)with excellent strength-ductility synergy under quasi-static tensile loading.However,it is questionable whether the EHEAs pos-sess equally good impact toughness because the phase interfaces are vulnerable to crack initiation.This work aimed to study the Charpy impact toughness and fracture behavior of AlCoCrFeNi_(2.1) EHEA.The results indicate that while maintaining high tensile strength and ductility,the AlCoCrFeNi_(2.1) EHEA also shows a satisfactory impact toughness of 25.86 J/cm^(2),superior to most other dual-phase alloys like TC4 titanium alloy or DP steel.Fractography analysis reveals characteristic regions of the fracture surface,which suggests energy absorption mechanisms primarily through ductile dimples,flat cleavage facets,secondary cracks,and microvoids,corresponding to a ductile-brittle mixed fracture mode.Detailed obser-vations of the deformed microstructure through TEM and EBSD demonstrate that FCC(L1_(2))and BCC(B2)phases underwent concurrent tearing along their phase boundaries,indicating a crucial influence of phase boundaries over crack initiation and propagation.The FCC(L1_(2))phase bore almost all plastic deformation of the sample through dislocation slip,whereas the BCC(B2)phase underwent a rapid shearing but almost no dislocation slip.Crack initiation under impact loading typically starts at the FCC(L1_(2))/BCC(B2)inter-face before propagating through the BCC(B2)phase.Additionally,this work further examines the effect of sample size and notch shape on the impact toughness of AlCoCrFeNi_(2.1) EHEA.A comparative analysis of the mechanical behavior under static and impact loading was also conducted,highlighting differences and connections in stress distribution and fracture surface morphology.The study offers valuable insights into the mechanical response and fracture behavior of AlCoCrFeNi_(2.1) EHEA under impact loading,provid-ing crucial information for its potential industrial applications.
基金supported by the National Natural Science Foundation of China(No.52271055)the Natural Science Foundation of Hebei Province(No.E2021202130).
文摘This work used the in-situ synthesis of molten-state nitride ceramic phase-reinforced Ni-based alloy coat-ings,aiming to improve the phase-interface bonding through the interdependent co-solidification be-tween molten droplets.The XRD was used to analyze the physical phases of the composite coatings.The microstructure and phase-interface structure were characterized in detail by combining SEM,TEM,HRTEM,FFT,and SAED techniques.Microhardness tester and microforce microhardness tester were em-ployed to measure the surface hardness and elastic modulus of the composite coatings.The fracture be-havior of the composite coatings was characterized by observing the fracture morphology of the coatings using SEM combined with the EDS technique.It was found that the formation mechanisms of inter-facial misfit dislocation assistance,lattice distortion,aggregation of stacking faults,and specific growth orientation between theγ-Ni matrix phase and each ceramic phase in NiCrBSi-TiCrN composite coat-ings improved the lattice matching between the two-phase interface,which resulted in the formation of atomically corresponding coherent lattice relations and stepped interfacial semi-coherent lattice relations,and enhanced the degree of phase-interface bonding.On this basis,the composite coatings with high Cr content further inhibited the expansion of interphase penetration cracks due to the existence of Cr-rich zones at the phase interface,thus exhibiting high fracture toughness.This work provides new opinions on the improvement of phase-interface bonding and composition design of Ni-based composite coatings.
基金supported by the National Natural Science Foundation of China(12202294)the Sichuan Science and Technology Program(2024NSFSC1346).
文摘Shape memory alloys(SMAs)and shape memory ceramics(SMCs)exhibit high recovery ability due to the martensitic transformation,which complicates the fracture mechanism of SMAs and SMCs.The phase field method,as a powerful numerical simulation tool,can efficiently resolve the microstructural evolution,multi-field coupling effects,and fracture behavior of SMAs and SMCs.This review begins by presenting the fundamental theoretical framework of the fracture phase field method as applied to SMAs and SMCs,covering key aspects such as the phase field modeling of martensitic transformation and brittle fracture.Subsequently,it systematically examines the phase field simulations of fracture behaviors in SMAs and SMCs,with particular emphasis on how crystallographic orientation,grain size,and grain boundary properties influence the crack propagation.Additionally,the interplay between martensite transformation and fracture mechanisms is analyzed to provide deeper insights into the material responses under mechanical loading.Finally,the review explores future prospects and emerging trends in phase field simulations of SMA and SMC fracture behavior,along with potential advancements in the fracture phase field method itself,including multi-physics coupling and enhanced computational efficiency for large-scale simulations.
基金supported by the National Natural Science Foundation of China(52474419,52374395)Natural Science Foundation of Shanxi Province(20210302123135,202303021221143)+3 种基金Scientific and Technological Achievements Transformation Guidance Special Project of Shanxi Province(202104021301022,202204021301009)Central Government Guided Local Science and Technology development projects(YDZJSX20231B003,YDZJSX2021A010)The Ministry of Science and Higher Education of the Russian Federation for financial support under the Megagrant(No.075-15-2022-1133)the National Research Foundation(NRF)grant funded by the Ministry of Science and ICT(2015R1A2A1A01006795)of Korea through the Research Institute of Advanced.
文摘In this work,AZ31B extruded sheets with mixed-grain microstructures were prepared through extrusion.Samples of mixed-grain microstructure with different morphologies were selected from the AZ31B extruded sheets(referred to as M1 and M2 samples,respectively).The creep tests were performed on these samples at the temperature range of 150-200℃,and the stress level range of 50-100 MPa.The creep properties and fracture behavior of AZ31 extruded sheets with mixed-grain microstructures were studied.Results showed that the creep properties of the M2 sample always outperformed that of the M1 sample and M1 and M2 samples’creep was dominated by dislocation movement.The creep rate of M2 samples(1.5×10^(-7)±1.1×10^(-10) s^(-1))is an order of magnitude lower than that of M1 samples(4.8×10^(-6)±8.1×10^(-10) s^(-1))at 200℃under 50 MPa The high activity of basal slip and softening mechanism in the M1 sample significantly accelerated creep,resulting in a relatively high creep rate.Moreover,the stress concentration within the M1 sample caused by deformation incompatibility,increased the initiation and propagation of voids,ultimately leading to fracture and poorer creep performance.However,the numerous<10µm fine grains surrounding deformed coarse grains in the M2 sample facilitated better coordination of deformation through dislocation slip,effectively slowing down the initiation of voids during the creep process.Meanwhile,the strain was uniformly distributed within each grain,mitigating stress concentration,inhibiting voids propagation,and contributing to the superior creep resistance of the M2 sample.
基金support of the National Natural Science Foundation of China(Grant Nos.52171056 and 52203385)the Joint Funds of the National Natural Science Foundation of China(Grant Nos.U2341255 and U22A20114)+1 种基金the Young Elite Scientists Sponsorship Program by CAST(Grant No.YESS20220225)the IMR Innovation Fund(Grant No.2021-ZD02).
文摘In dry storage,spent fuel is typically stored in casks constructed from neutron absorbing materials(NAMs).The(B_(4)C+Al_(2)O_(3))/Al composite,which incorporates in-situ amorphous Al_(2)O_(3)(am-Al_(2)O_(3))formed on fine aluminum powder as a reinforcing phase,can serve as an integrated structural and functional NAM for dry storage applications.Welding is crucial in the fabrication of these casks.In this study,friction stir welding was performed on(B_(4)C+Al_(2)O_(3))/Al composite sheets at a welding speed of 50 mm/min and rotation rates ranging from 500 to 1000 r/min.The microstructure of the weld joints was analyzed,and the intrinsic relationship between fracture behavior and microstructure was elucidated.Results showed that defect-free joints were achieved at rotation rates of 500 and 750 r/min,while tunnel defects were observed at 1000 r/min.The ultimate tensile strength of the joint welded at 500 r/min was 205.7 MPa,with a strength efficiency of 82%.Microstructural analysis revealed that the grains within the nugget zones(NZs)coarsened and the Al_(2)O_(3)network was disrupted due to the welding thermo-mechanical effect,resulting in softening within the NZs.Fracture locations for all three joints were consistently observed at the NZ boundary on the advancing side(AS).Finite element simulations confirmed that cracks propagated along the NZ boundary on the AS,where stress concentration occurred during tensile testing.
基金the supports provided by the National Natural Science Foundation of China(Nos.52075198 and 52271102)the China Postdoctoral Science Foundation(No.2021M691112)+1 种基金the State Key Lab of Advanced Metals and Materials(No.2021-ZD07)the Analytical and Testing Center,HUST。
文摘In this paper,the effect of the Si content on microstructure evolution,mechanical properties,and fracture behavior of the Al-xSi/AZ91D bimetallic composites prepared by compound casting was investigated systematically.The obtained results showed that all the Al-xSi/AZ91D bimetallic composites had a metallurgical reaction layer(MRL),whose thickness increased with increasing Si content for the hypoeutectic Al-Si/AZ91D composites,while the hypereutectic Al-Si/AZ91D composites were opposite.The MRL included eutectic layer(E layer),intermetallic compound layer(IMC layer)and transition region layer(T layer).In the IMC layer,the hypereutectic Al-Si/AZ91D composites contained some Si solid solution and flocculent Mg_(2)Si+Al-Mg IMCs phases not presented in the hypoeutectic Al-Si/AZ91D composites.Besides,increasing Si content,the thickness proportion of the T layer increased,forming an inconsistent preferred orientation of the MRL.The shear strengths of the Al-xSi/AZ91D bimetallic composites enhanced with increasing Si content,and the Al-15Si/AZ91D composite obtained a maximum shear strength of 58.6 MPa,which was 73.4% higher than the Al-6Si/AZ91D composite.The fractures of the Al-xSi/AZ91D bimetallic composites transformed from the T layer into the E layer with the increase of the Si content.The improvement of the shear strength of the Al-xSi/AZ91D bimetallic composites was attributed to the synergistic action of the Mg_(2)Si particle reinforcement,the reduction of oxidizing inclusions and the ratio of Al-Mg IMCs as well as the orientation change of the MRL.
基金National Natural Science Foundation of China(52305349)China Postdoctoral Science Foundation(2023M730837)+2 种基金Natural Science Basic Research Program of Shaanxi Province(2023-JC-QN-0518)Heilongjiang Provincial Natural Science Foundation of China(LH2023E033)Supported by CGN-HIT Advanced Nuclear and New Energy Research Institute(CGN-HIT202305)。
文摘The mechanical properties and fracture morphologies of Cu/Nb multilayer composites under electric-assisted tension(EAT)were investigated.Results show that the generated Joule-heat leads to obvious stress softening with the increase in current density.However,the elongation decreases,which is closely related to the characteristic fracture behavior of Cu/Nb multilayer composites during EAT.The fracture pattern is gradually transformed from ductile fracture to melt fracture with the increase in current density.
基金supported financially by the Natural Science Foundation of Qinghai(2022-ZJ-928)the Special Project for Transformation of Scientific and Technological Achievements of Qinghai Province(2023-GX-102).
文摘The lamellar hydrates of CAC were designed with the introduction of nano CaCO_(3)or Mg-Al hydrotalcite(M-A-H),and the effects on the green strength,pore structures,and high-temperature fracture behavior of alumina-spinel castables were investigated.The results show that nano CaCO_(3)or M-A-H stimulates rapidly the hydration of CAC and the formation of lamellar C_(4)AcH_(11)or coexistence of C_(2)AH_(8)and C_(4)AcH_(11)at 25℃.The formation of lamellar hydrates can contribute to a more complicated pore structure,especially in the range of 400-2000 nm.Meanwhile,the incorporation of well-distributed CaO or MgO sources from nano CaCO_(3)or M-A-H also regulates the distribution of CA_(6)and spinel(pre-formed and in-situ).Consequently,the optimized microstructure and complicated pore structure can induce the deflection and bridging of cracks,thus facilitating the consumption of fracture energy and enhancing the resistance to thermal stress damage.
基金Project(51174244) supported by the National Natural Science Foundation of ChinaProject(CDJZR11130005) supported by the Fundamental Research Funds for the Central Universities,China
文摘An aluminum-based in-situ composites reinforced with Mg2Si and Si particles were produced by centrifugal casting A1-20Si-5Mg alloy. The microstructure of the composites was examined, and the effects of temperature on fracture behavior of the composite were investigated. The results show that the average fraction of primary Si and Mg2Si particles in the composites is as high as 38%, and ultimate tensile strengths （UTS） of the composites first increase then decrease with the increase of test temperature. Microstructures of broken specimens show that both the particle fracture and the interface debonding affect the fracture behavior of the composites, and the interface debonding becomes the dominant fracture mechanism with increasing test temperature. Comparative results indicate that rich particles in the composites and excellent interface strength play great roles in enhancing tensile property by preventing the movement of dislocations.
基金Project(IRT0713) supported by the Program for Changjiang Scholars and Innovative Research Team in Chinese UniversityProjects(2007CB613701,2007CB613702) supported by the National Basic Research Program of China
文摘The effects of plastic deformation on precipitation behavior and tensile fracture behavior of Mg-10Gd-3Y-0.6Zr alloy were investigated.The results indicate that more precipitation cores can be provided by the crystal defects caused by the plastic deformation,as well as increasing the amount of β＇ phases,and the formation of precipitations at grain boundaries and interfaces between the twins and matrix.Because of an increase in precipitations,the dislocation slipping during deformation process is effectively hindered and the matrix is strengthened,especially for the 2% deformed alloy which can achieve a good combination of strength and ductility.With increasing the plastic deformation,the microcracks occur at the interface between grain boundary precipitations and matrix,and then propagate intergranularly.When intergranular fracture combines with the formation of smoothing facets on the fracture surface,the tensile properties decrease.
文摘2219-T8 aluminum alloys were butt welded by the double-pass tungsten inert gas （TIG） arc welding process. The transverse tensile test of the joint showed that the fracture mainly occurred in the partially melted zone （PMZ）. Effects of the PMZ on the fracture behavior were systematically studied. Continuous intergranular eutectics were observed in the PMZ close to the fusion line. Away from the fusion line, the intergranular eutectics in the PMZ became discontinuous. The fracture morphology and the microhardness distribution of the joint showed that the PMZ was gradient material with different mechanical properties, which strongly affected the fracture process. It was observed that the crack initiated in the PMZ near the front weld toe, and propagated in the PMZ away from the fusion line. Then, the crack tip was blunt when it propagated into the PMZ with higher plasticity. Finally, the rest part of the joint was shear fractured.
基金Project(2010CB731706) supported by the National Basic Research Program of China
文摘The strength and fatigue fracture behavior of A1-Zn-Mg-Cu-Zr（-Sn） alloys were studied by performing tensile tests and fatigue crack propagation （FCP） tests. The microstructures of the experimental alloys were further analyzed using optical microscopy （OM）, scanning electron microscopy （SEM）, and transmission electron microscopy （TEM）; phase analysis of these alloys was conducted with an X-ray diffraction （XRD）. The results show that when Sn is included, growth of the recrystallization grains in the solution-treated A1-Zn-Mg-Cu-Zr alloy is obstructed, the precipitation-free zone （PFZ） of the overaged A1-Zn-Mg-Cu-Zr-Sn alloy becomes narrow, and the grain boundary precipitates are smaller. Consequently, the FCP resistance is higher. In addition, the overaged Sn-containing alloy has considerably higher tensile strength than the alloy without Sn.
基金Project (51071056) supported by the National Natural Science Foundation of ChinaProject (HEUCFR1132) supported by the Fundamental Research Funds for the Central Universities of China
文摘The as-cast ingot of equiatomic nickel-titanium shape memory alloy （NiTi SMA） was prepared by vacuum consumable arc melting. The tensile tests and the compressive tests with respect to as-cast NiTi SMA were performed to study its mechanical properties of fracture. The microanalysis of as-cast NiTi SMA as well as its fractured samples was performed so as to better understand microstructure evolution and fracture behavior of NiTi SMA. Under tensile loading, the as-cast NiTi SMA shows higher plasticity and is characterized by ductile fracture at 750℃, but it demonstrates poorer plasticity and is characterized by cleavage fracture as well as transcrystalline fracture at room temperature and -100 ℃. Under compressive loading at -100 ~C, the as-cast NiTi SMA is characterized by shear fracture where the normal to the shearing fracture surface inclines about 45° to the compressive axis, and belongs to cleavage fracture where the cracks exoand via transcrvstalline fracture.
文摘Using an optical microscope and scanning electron microscope (SEM), the variation of eutectic Si morphology of Al-Si alloy in solution treatment was observed to study its influence on mechanical properties and fracture behavior. The results show that eutectic Si undergoes stubbing, necking, fragmentation, and growth in the initial stage (250 min); in the middle solution stage (250 to 400 min), the eutectic Si morphology has no significant change, only the degree of spheroidizing becomes higher; after 600 min, the growth of eutectic Si is a coarsening process controlled by diffusion and follows the Liftshitz-Slyozov-Wangner (LSW) model, and the eutectic Si morphology deteriorates due to the occurrence of facets and lap. Based on the quantitative measure and regression analysis, the eutectic Si morphology has a remarkable influence on mechanical properties and fracture behavior.
基金Project(2007CB613704) supported by the National Basic Research Program of China
文摘The fracture behavior of a permanent mould casting Mg-8.57Gd-3.72Y-0.54Zr(mass fraction,%)(GW94) alloy was investigated under different thermal conditions,including as-cast,solution-treated,peak-aged,and over-aged states.Scanning electron microscopy(SEM) and optical microscopy(OM) were employed to examine the crack nucleation and fracture model.The results indicate that the GW94 alloy shows different behaviors of crack initiation and fracture under different thermal conditions. During tensile test at room temperature,the fracture model of the as-cast GW94 alloy is quasi-cleavage,while that of the solution-treated alloy is transgranular cleavage.It is a mixed pattern of transgranular and intergranular fracture for both the aged conditions.Large cavities formed at grain boundaries are observed in the peak-aged sample tested at 300℃,corresponding to the intergranular fracture.Localized plastic deformation at grain boundaries is also observed and corresponds to the high elongation at 300℃.
基金supported by the National Natural Science Foundation of China (Nos.51525101 and 51371046)the Program for New Century Excellent Talents in University (No.NECT-12-0109)the Fundamental Research Funds for the Central Universities (Nos.N130510002,N141008001)
文摘In the present work, Zn-（0-1）Mg（wt%） alloys were prepared by casting and indirect extrusion at 200 and300 ℃, respectively. With Mg addition, both the size and amount of second phase Mg2Zn（11） increased, and the equiaxed grains were significantly refined. The extrusion temperature had little influence on Mg2Zn（11）, but the grains were refined at low extrusion temperature. For the alloys extruded at 200 ℃, as Mg content increased, the tensile yield strength（TYS）increased from 64 MPa for pure Zn to 262 MPa for Zn-1Mg; the elongation increased from 14.3% for pure Zn to 25% for Zn-0.02Mg and then decreased to 5% for Zn-1Mg. For the alloys extruded at 300 ℃, as Mg content increased, the TYS increased from 67 MPa for pure Zn to 252 MPa for Zn-1Mg, while the elongation decreased from 11.7% to 2%. The alloy extruded at 200 ℃ exhibited higher TYS and elongation than the corresponding alloy extruded at 300 ℃. The combination of grain refinement and second phase Mg2Zn（11） contributed to the improvement in the TYS, and the grain refinement played a major role in strengthening alloy. Zn-0.02Mg and Zn-0.05Mg alloys extruded at 200 ℃ show a mixture of cleavage and ductile fracture corresponding to higher elongation, while the other alloys show cleavage fracture.
