Friction stir lap welding of AA2195 Al-Li alloy and Ti alloy was conducted to investigate the formation,microstructure,and mechanical properties of the joints.Results show that under different welding parameters,with ...Friction stir lap welding of AA2195 Al-Li alloy and Ti alloy was conducted to investigate the formation,microstructure,and mechanical properties of the joints.Results show that under different welding parameters,with the decrease in welding heat input,the weld surface is smoother.The Ti/Al joint interface is flat without obvious Ti and Al mixed structure,and the hook structure is not formed under optimal parameters.Due to the enhanced breaking effect of the stirring head,the hook structural defects and intermetallic compounds are more likely to form at the Ti/Al interface at high rotational speed of 1000 r/min,thereby deteriorating the mechanical properties of joints.Decreasing the heat input is beneficial to hardness enhancement of the aluminum alloy in the weld nugget zone.Under the optimal parameters of rotation speed of 800 r/min and welding speed of 120 mm/min,the maximum tensile shear strength of joint is 289 N/mm.展开更多
1.Introduction The strength-ductility trade-offdilemma has long been a per-sistent challenge in Al matrix composites(AMCs)[1,2].This is-sue primarily arises from the agglomeration of reinforcements at the grain bounda...1.Introduction The strength-ductility trade-offdilemma has long been a per-sistent challenge in Al matrix composites(AMCs)[1,2].This is-sue primarily arises from the agglomeration of reinforcements at the grain boundaries(GBs),which restricts local plastic flow dur-ing the plastic deformation and leads to stress concentration[3,4].Recently,the development of concepts aimed at achieving hetero-geneous grain has emerged as a promising approach for enhanc-ing comprehensive mechanical properties[5,6].展开更多
High-strength aluminum alloys are widely used in industries such as aerospace,automotive,and defense due to their excellent strength-to-weight ratio and good mechanical properties.However,optimizing their mechanical p...High-strength aluminum alloys are widely used in industries such as aerospace,automotive,and defense due to their excellent strength-to-weight ratio and good mechanical properties.However,optimizing their mechanical properties while maintaining cost-effectiveness and processing efficiency remains a significant challenge.This paper investigates the fundamental aspects of microstructure control and mechanical property optimization in high-strength aluminum alloys.It focuses on the influence of alloy composition,heat treatments,and processing techniques on the material's strength,ductility,toughness,fatigue resistance,corrosion resistance,and wear properties.The paper also explores the role of advanced experimental techniques,such as metallographic analysis,mechanical testing,and X-ray diffraction(XRD),in characterizing the microstructure and mechanical performance of these alloys.Moreover,it emphasizes the importance of microstructure refinement,solid solution strengthening,precipitation hardening,and the addition of specific alloying elements in optimizing the alloy's overall performance.The review provides valuable insights into the key strategies for designing high-strength aluminum alloys with enhanced mechanical properties,focusing on their applications in high-performance engineering fields.展开更多
The influence of alloying dysprosium(Dy)element on the biodegradable behavior and mechanical prop-erty of Mg-6 Zn alloys in a simulated body solution(SBF)solution was studied.The results indicate that Dy significantly...The influence of alloying dysprosium(Dy)element on the biodegradable behavior and mechanical prop-erty of Mg-6 Zn alloys in a simulated body solution(SBF)solution was studied.The results indicate that Dy significantly contributes to grain refinement,and form a distinctive fiber texture in Dy-containing al-loys.The presence of Dy promotes the formation of granular DyZn3 precipitates,which possess a higher electrode potential than the matrix,thus accelerating matrix corrosion.Corrosion results demonstrate that the Dy element is not beneficial to reducing the initial corrosion rate of Mg-6 Zn but is conducive to improving the protective effect of product film as the immersion time increases.Dy-containing alloys exhibit higher strength than Mg-6 Zn while maintaining good plasticity related to grain boundary and precipitation strength effects.Consequently,the incorporation of 2 wt.%Dy into Mg-6 Zn alloys results in a synergistic enhancement of strength,as well as moderate corrosion resistance and fracture elongation.展开更多
Zinc(Zn)-based materials show broad application prospects for bone repair due to their biodegradability and good biocompatibility.In particular,Zn metal foam has unique interconnected pore structure that facilitates i...Zinc(Zn)-based materials show broad application prospects for bone repair due to their biodegradability and good biocompatibility.In particular,Zn metal foam has unique interconnected pore structure that facilitates inward growth of new bone tissue,making it ideal candidates for orthopedic implants.However,pure Zn metal foam shows poor mechanical property,high degradation rate,and unsatisfactory osteogenic activity.Herein,Zinc-manganese(Zn-Mn)alloy foams were electrodeposited in Zn and Mn-containing electrolytes to overcome the concerns.The results showed that Mn could be incorporated into the foams in the form of MnZn_(13).Zn-Mn alloy foams showed better mechanical property and osteogenic activity as well as moderate degradation rate when compared with pure Zn metal foam.In addition,these properties could also be regulated by preparation process.The peak stress and osteogenic activity increased with deposition current(0.3‒0.5 A)and electrolyte pH(3‒5),but decreased with electrolyte temperature(20‒40℃),while the degradation rate exhibited opposite tendency,which suggests high deposition current and electrolyte pH and low electrolyte temperature can fabricate Zn-Mn alloy foam with favorable mechanical property,moderate degradation rate,and osteogenic activity.These findings provide a valuable reference for the design and fabrication of novel Zn-based biodegradable materials.展开更多
The surface of MoSi2-SiB6/phenolic resin matrix composites was modified by mica,and the thermal oxidation behavior of the composites and the mechanical properties of the pyrolysis products were studied.The results sho...The surface of MoSi2-SiB6/phenolic resin matrix composites was modified by mica,and the thermal oxidation behavior of the composites and the mechanical properties of the pyrolysis products were studied.The results showed that the mica improved the thermal properties of the composites,the thermal expansion coefficient decreased,and the liquid phase formation caused the composites to shrink and increase the density.The flexural strength of mica surface modified composites not only increased to 78.64MPa after thermal treatment at 800-1200℃,but reached 83.02 MPa after high temperature treatment at1400℃.The improvement of the mechanical properties of the residual product benefits from the formation of high temperature ceramic phases such as Mo_(2)C and MoB,and the improvement of the shear strength of the composites by the mica.The shear strength of MBm5-2 at room temperature reached 33.08 MPa,indicating that the improvement of the interlayer properties of the composites further improved its mechanical properties.展开更多
In order to solve the black-box modeling problem and improve the prediction accuracy of model,two distinguished models for tensile strength(Ts)and yield strength(Ys)of hot-rolled strip steel are established based on t...In order to solve the black-box modeling problem and improve the prediction accuracy of model,two distinguished models for tensile strength(Ts)and yield strength(Ys)of hot-rolled strip steel are established based on the industrial hot-rolled data and the algorithm of gene expression programming(GEP).Firstly,the industrial data of hot-rolled strip steel are preprocessed using the Pauta criterion,so as to eliminate outliers.The key input variables that affect Ys and Ts are selected by using the method of the maximal information coefficient(MIC).Secondly,the explicit prediction models of Ys and Ts are established using GEP.Subsequently,the model results based on GEP are compared with those based on the support vector regression(SVR)and the back propagation neural network(BPNN).Finally,the mathematical expression models for Ys and Ts obtained by GEP are used to further analyse the specific relationships between the chemical composition and mechanical property.It is shown that the errors of Ys and Ts based on GEP are less than 4%,and the coefficient of determination(R^(2))of Ys and Ts based on GEP is above 0.9,which has strong prediction performance.The prediction accuracy of GEP can achieve the same level with SVR and BPNN.It is worth mentioning that the proposed model can not only show the explicit relationship between the chemical composition,production process,and mechanical property of strip steel,but also occupy high prediction accuracy,which can make reliable reference for strip steel product design and optimisation.展开更多
Correction to:J.Iron Steel Res.Int.https://doi.org/10.1007/s42243-025-01545-x The publication of this article unfortunately contained mistakes.Equation(14)was not correct.The corrected equation is given below.
Low temperature mechanical properties of AZ91D magnesium alloy fabricated by solid recycling process from recycled scraps were studied. Various microstructural analyses were performed using optical microscopy （OM） a...Low temperature mechanical properties of AZ91D magnesium alloy fabricated by solid recycling process from recycled scraps were studied. Various microstructural analyses were performed using optical microscopy （OM） and scanning electron microscopy （SEM）. The recycled specimens consist of fine grains due to dynamic recrystallization and the interfaces of original individual scraps are not identified. Tensile tests were performed at a strain rate of 5 x 10 3 s 1 at room temperature （27 ~C）, -70, -100 and 130 ~C, respectively. Ultimate tensile strength of the specimens increases slightly with decreasing the tensile temperature, and elongation to failure decreases with decreasing the tensile temperature. The tensile specimens at -130 ~C show the highest ultimate tensile strength of 360.65 MPa and the lowest elongation to failure of 5.46%. Impact tests were performed at room temperature （27 ~C）, -70 and -130 ~C, respectively. Impact toughness decreases with decreasing the impact temperature. The impact specimens at -130 ~C show the lowest impact toughness of 3.06 J/cm2.展开更多
Microstructures and phase compositions of as-cast and extruded ZK60-xGd （x=0-4） alloys were investigated. Meanwhile, the tensile mechanical property was tested. With increasing the Gd content, as-cast microstructure...Microstructures and phase compositions of as-cast and extruded ZK60-xGd （x=0-4） alloys were investigated. Meanwhile, the tensile mechanical property was tested. With increasing the Gd content, as-cast microstructure is refined gradually. Mg-Zn-Gd new phase increases gradually, while MgZn2 phase decreases gradually to disappear. The second phase tends to distribute along grain boundary by continuous network. As-cast tensile mechanical property is reduced slightly at ambient temperature when the Gd content does not exceed 2.98%. After extrusion by extrusion ratio of 40 and extrusion temperature of 593 K, microstructure is refined further with decreasing the average grain size to 2 μm for ZK60-2.98Gd alloy. Broken second phase distributes along the extrusion direction by zonal shape. Extruded tensile mechanical property is enhanced significantly. Tensile strength values at 298 and 473 K increase gradually from 355 and 120 MPa for ZK60 alloy to 380 and 164 MPa for ZK60-2.98Gd alloy, respectively. Extruded tensile fractures exhibit a typical character of ductile fracture.展开更多
Multimaterial digital light processing(DLP)three-dimensional(3D)printing technology provides unique advantages in the field of multi material additive manufacturing(MM AM)with its high resolution and rapid shaping cap...Multimaterial digital light processing(DLP)three-dimensional(3D)printing technology provides unique advantages in the field of multi material additive manufacturing(MM AM)with its high resolution and rapid shaping capabilities based on photopolymerization.However,owing to differences in the curing behavior and physical properties of different materials,multimaterial DLP 3D printing faces challenges such as insufficient interfacial bonding strength and unstable mechanical properties.In this study,two resins were integrated by multimaterial DLP 3D printing technology,and the effects of different layer thicknesses and exposure times on the interfacial bonding strength and morphology of the multimaterials were systematically investigated.The interfacial bonding mechanisms of the two resins was analyzed.It was found that increasing the exposure time can improve the interfacial bonding strength between materials,but certain limitations exist.A mathematical model relating the interfacial bonding strength to the exposure time and layer thickness was developed,and optimal process parameters were determined using optimization algorithms.A variable-parameter printing strategy for the interface was proposed to further improve the performance of printed parts.The maximum tensile strength of the multimaterial samples(44.43 MPa)using this strategy reached that of single-material parts(45 MPa),validating the feasibility of this strategy.This provides guidance for multimaterial DLP 3D printing processes and offers valuable insights for the future additive manufacturing of high-performance multimaterial components.展开更多
This study develops novel Mg-Sn-In-Ga alloys as potential implant materials for orthopedic applications.The corrosion behavior of the Mg-Sn-In-Ga alloys was studied through mass loss measurements,hydrogen evolution me...This study develops novel Mg-Sn-In-Ga alloys as potential implant materials for orthopedic applications.The corrosion behavior of the Mg-Sn-In-Ga alloys was studied through mass loss measurements,hydrogen evolution measurements,electrochemical analysis,and corrosion morphology observations.The results show that the corrosion rate of the Mg-1Sn-1In-1Ga alloy was only 0.10±0.003 mm/y after immersion in Hank’s solution for 15 days.This outstanding corrosion resistance was associated with the protective efect of the corrosion products.The increase in the Sn and Ga element content led to the precipitation of a large amount of Mg_(2)Sn and Mg_(5)Ga_(2),which had a dominant efect on the corrosion rate in the Mg-5Sn-1In-2Ga alloy.These precipitates increased the current density and detached from the alloy surface during the corrosion process.This can lead to a weakened protective efect of the corrosion layer,and thus generate localized corrosion and an increase in the corrosion rate.The strength of the Mg-5Sn-1In-2Ga alloy was enhanced due to fne-grain strengthening and precipitation strengthening.The ultimate tensile strength and yield strength of the Mg-5Sn-1In-2Ga alloy were~309 MPa and~253 MPa,respectively.展开更多
The cold radial forging process usually introduces some changes of the material, such as the increased strength, the decreased plasticity and the introduction of anisotropic mechanical prop- erty. To obtain the change...The cold radial forging process usually introduces some changes of the material, such as the increased strength, the decreased plasticity and the introduction of anisotropic mechanical prop- erty. To obtain the changes of mechanical property of barrel processed by cold radial forging, the tangential mechanical properties of the barrel blank and the forged barrel are measured with a de- signed test based on the plastic deformation analysis for a barrel and by applying internal pressure, and their axial mechanical properties are measured by the tensile test. The changes of mechanical property of barrel processed by cold radial forging are obtained by comparing the mechanical proper- ties of the barrel blank and the forged barrel. The tangential and axial flow stresses of the barrel blank and the forged barrel are also presented.展开更多
The effect of heat treatment on microstructure and mechanical properties of the Ti-steel explosive-rolling clad plate was elaborated by optical microscopy （OM）, scanning electron microscopy （SEM）, X-ray diffracti...The effect of heat treatment on microstructure and mechanical properties of the Ti-steel explosive-rolling clad plate was elaborated by optical microscopy （OM）, scanning electron microscopy （SEM）, X-ray diffraction （XRD）, transmission electron microscopy （TEM）, micro-hardness test and shear test. The composites were subjected to heat treatment at temperature of 650-950 ~C for 60 min. The results show that the heat treatment process results in a great enhancement of diffusion and microstructural transformation. The shear strength decreases as the treatment temperature increases. Heated at 850 ℃ or below, their shear strength decreases slowly as a result of the formation of TiC in the diffusion interaction layer; while at the temperature of 850 ℃ or above, the shear strength decreases obviously, which is the consequence of a large amount of Ti-Fe intermetaUics （Fe2Ti/FeTi） along with some TiC distributing continuously at diffusion reaction layer.展开更多
The mixed grain structure and mechanical property anisotropy of AZ40 magnesium alloy bar with a diameter of 160 mm manufactured by ＂multi-direction forging（MDF） ＋ extrusion ＋ online cooling＂ technique were inves...The mixed grain structure and mechanical property anisotropy of AZ40 magnesium alloy bar with a diameter of 160 mm manufactured by ＂multi-direction forging（MDF） ＋ extrusion ＋ online cooling＂ technique were investigated by optical microscopy（OM）, scanning electron microscopy（SEM）, X-ray diffraction macro-texture measurement and room temperature（RT） tensile test. The results show that mixed grain structure is caused by the micro-segregation of Al in semi-continuous casting ingot. Homogenization of（380 °C, 8 h） ＋（410 °C, 12 h） cannot totally eliminate such micro-segregation. During MDF and extrusion, the dendrite interiors with 3%-4% Al（mass fraction） transform to fine grain zones, yet the dendrite edges with about 6% Al transform to coarse grain zones. XRD macro-textures of the outer, R/2 and center show typical fiber texture characteristics and the intensity of [0001]//Ra D orientation in the outer（11.245） is about twice as big as those in the R/2（6.026） and center（6.979）. The as-extruded AZ40 magnesium alloy bar has high elongation（A） and moderate ultimate tensile strength（Rm） in both extrusion direction（ED） and radius direction（Ra D）, i.e., A of 19%-25% and Rm of 256-264 MPa; however, yield strength（Rp0.2） shows anisotropy and heterogeneity, i.e., 103 MPa in Ra D, 137 MPa in ED-C（the center） and 161 MPa in ED-O（the outer）, which are mainly caused by the texture.（155 °C, 7 h） ＋（170 °C, 24 h） aging has no influence on strength and elongation of AZ40 magnesium bar.展开更多
The effects of addition of La on the microstructure of as-cast ADC12 A1-Alloy were investigated by using optical microscope （OM）, X-ray diffraction （XRD）, scanning electron microscope （SEM）, and energy disperse ...The effects of addition of La on the microstructure of as-cast ADC12 A1-Alloy were investigated by using optical microscope （OM）, X-ray diffraction （XRD）, scanning electron microscope （SEM）, and energy disperse spectroscopy （EDS）. The experimental results showed that the a-A1 and eutectic Si crystals were modified with the addition of 0.3 wt% La. The eutectic Si crystals showed a granular distribution. At the same time, the alloy possessed the best mechanical property. When more than 0.3 wt% La was added to ADC12 aluminum alloy, the microstructure of as-cast alloy was coarsening gradually with the increase of the content of La and the mechanical property decreased. The effect of rare earth La which was added in ADC 12 A1-Alloy for up to 0.9 wt% had been investigated in this study. The dendrites ofADC12 Al-alloy was refined obviously and the morphology of Si crystals showed a particle structure when the addition of La reached 0,3 wt%. Besides, the acicular La-rich intermetallics in the alloy deteriorated the mechanical property of alloy： To avoid this unwanted phase, the amount of added rare earth La must be less than 0.6 wt%.展开更多
Effect of thermal stabilization on the microstructure and mechanical property of directionally solidified Ti-46Al-0.5W-0.5Si （mole fraction, %） alloy was investigated. The specimens were thermal stabilized for diffe...Effect of thermal stabilization on the microstructure and mechanical property of directionally solidified Ti-46Al-0.5W-0.5Si （mole fraction, %） alloy was investigated. The specimens were thermal stabilized for different time （t） and directionally solidified at a constant growth rate of 30 μm/s and temperature gradient of 20 K/mm. Dependencies of the primary dendritic spacing （λ1）, secondary dendritic spacing （λ2）, interlamellar spacing （λL） and microhardness （HV） on holding time were determined. The values of the λ1, λ2 and λL increase with the increase of t, and the value of HV decreases with the increase of t. The increase of t is helpful to obtain a good directional solidification structure. However, it reduces the mechanical property of the directionally solidified TiAl alloy. The optimized value of t is about 30 min.展开更多
The influence of Li addition on mechanical property and aging precipitation behavior of Al-3.5Cu-1.5Mg alloy was investigated by tensile test,scanning electron microscopy（SEM）,transmission electron microscopy（TEM）...The influence of Li addition on mechanical property and aging precipitation behavior of Al-3.5Cu-1.5Mg alloy was investigated by tensile test,scanning electron microscopy（SEM）,transmission electron microscopy（TEM） and high resolution transmission electron microscopy（HRTEM）.The results show that the tensile strength can be significantly improved with the slightly decreased ductility and the form of fracture morphology is converted from ductile fracture into ductile/britde mixed fracture by adding 1.0%Li.Besides,the peak aging time at 185 ℃ is delayed from 12 to 24 h and the main precipitation phase S（Al2CuMg） is converted into S＇（Al2CuMg）＋δ（Al3Li）,while the formation of S＇（Al2CuMg） is delayed.展开更多
Constructing bimodal grain structure is a promising approach to achieve the high strength-ductility syn-ergy in Mg alloy.Formation of bimodal grain is closely related to the dynamic and/or static recrystal-lization pr...Constructing bimodal grain structure is a promising approach to achieve the high strength-ductility syn-ergy in Mg alloy.Formation of bimodal grain is closely related to the dynamic and/or static recrystal-lization process,which has not been fully understood in the typical Mg-RE based alloy.In this work,it is claimed for the first time that the minor Ce addition(∼0.3 wt%)into Mg matrix significantly pro-motes the pyramidal<c+a>and non-basal<a>dislocations at the early stage of extrusion,which con-sequently enhances the formation of sub-grain boundaries via the movement and recovery of pyramidal II-type<c+a>dislocations.At this stage,fine sub-grain lamellae are widely observed predominantly due to the low migration rate of sub-grain boundary caused by the limited mobility of<c+a>dislocations.At the later stage,the sub-grains continuously transform into dynamic recrystallized(DRXed)grains that have10¯10Taylor axis and also strong fiber texture,indicating substantial activation of pyramidal II-type<c+a>dislocation.The low mobility of<c+a>dislocations,accompanied with the solute drag from grain boundary(GB)segregation and pinning from nano-phases,cause a sluggish DRX process and thus a bimodal microstructure with ultra-fined DRXed grains,∼0.51μm.The resultant texture hardening and grain refinement hardening effects,originated from bimodal microstructure,result in a yield strength of∼352 MPa,which is exceptional in Mg-Ce dilute alloy.This work clarifies the critical role of Ce addition in tuning recrystallization behavior and mechanical property of magnesium,and can also shed light on designing the other high-performance Mg alloys.展开更多
Mechanical property prediction of hot rolled strip is one of the hotspots in material processing research. To avoid the local infinitesimal defect and slow constringency in pure BP algorithm, a kind of global optimiza...Mechanical property prediction of hot rolled strip is one of the hotspots in material processing research. To avoid the local infinitesimal defect and slow constringency in pure BP algorithm, a kind of global optimization algorithm-particle swarm optimization （PSO） is adopted. The algorithm is combined with the BP rapid training algorithm, and then, a kind of new neural network （NN） called PSO-BP NN is established. With the advantages of global optimization ability and the rapid constringency of the BP rapid training algorithm, the new algorithm fully shows the ability of nonlinear approach of multilayer feedforward network, improves the performance of NN, and provides a favorable basis for further online application of a comprehensive model.展开更多
基金National Natural Science Foundation of China(52275349)Key Research and Development Program of Shandong Province(2021ZLGX01)。
文摘Friction stir lap welding of AA2195 Al-Li alloy and Ti alloy was conducted to investigate the formation,microstructure,and mechanical properties of the joints.Results show that under different welding parameters,with the decrease in welding heat input,the weld surface is smoother.The Ti/Al joint interface is flat without obvious Ti and Al mixed structure,and the hook structure is not formed under optimal parameters.Due to the enhanced breaking effect of the stirring head,the hook structural defects and intermetallic compounds are more likely to form at the Ti/Al interface at high rotational speed of 1000 r/min,thereby deteriorating the mechanical properties of joints.Decreasing the heat input is beneficial to hardness enhancement of the aluminum alloy in the weld nugget zone.Under the optimal parameters of rotation speed of 800 r/min and welding speed of 120 mm/min,the maximum tensile shear strength of joint is 289 N/mm.
基金support by the National Natural Science Foundation of China(Grant Nos.U23A20546 and 52271010)the Chinese National Natural Science Fund for Distinguished Young Scholars(Grant No.52025015)the Natural Science Foundation of Tianjin City(No.21JCZDJC00510).
文摘1.Introduction The strength-ductility trade-offdilemma has long been a per-sistent challenge in Al matrix composites(AMCs)[1,2].This is-sue primarily arises from the agglomeration of reinforcements at the grain boundaries(GBs),which restricts local plastic flow dur-ing the plastic deformation and leads to stress concentration[3,4].Recently,the development of concepts aimed at achieving hetero-geneous grain has emerged as a promising approach for enhanc-ing comprehensive mechanical properties[5,6].
文摘High-strength aluminum alloys are widely used in industries such as aerospace,automotive,and defense due to their excellent strength-to-weight ratio and good mechanical properties.However,optimizing their mechanical properties while maintaining cost-effectiveness and processing efficiency remains a significant challenge.This paper investigates the fundamental aspects of microstructure control and mechanical property optimization in high-strength aluminum alloys.It focuses on the influence of alloy composition,heat treatments,and processing techniques on the material's strength,ductility,toughness,fatigue resistance,corrosion resistance,and wear properties.The paper also explores the role of advanced experimental techniques,such as metallographic analysis,mechanical testing,and X-ray diffraction(XRD),in characterizing the microstructure and mechanical performance of these alloys.Moreover,it emphasizes the importance of microstructure refinement,solid solution strengthening,precipitation hardening,and the addition of specific alloying elements in optimizing the alloy's overall performance.The review provides valuable insights into the key strategies for designing high-strength aluminum alloys with enhanced mechanical properties,focusing on their applications in high-performance engineering fields.
基金supported by the National Natural Science Foundation of China(No.52301133)the China Postdoctoral Science Foundation(No.2023M730276)the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(No.YESS20210415).
文摘The influence of alloying dysprosium(Dy)element on the biodegradable behavior and mechanical prop-erty of Mg-6 Zn alloys in a simulated body solution(SBF)solution was studied.The results indicate that Dy significantly contributes to grain refinement,and form a distinctive fiber texture in Dy-containing al-loys.The presence of Dy promotes the formation of granular DyZn3 precipitates,which possess a higher electrode potential than the matrix,thus accelerating matrix corrosion.Corrosion results demonstrate that the Dy element is not beneficial to reducing the initial corrosion rate of Mg-6 Zn but is conducive to improving the protective effect of product film as the immersion time increases.Dy-containing alloys exhibit higher strength than Mg-6 Zn while maintaining good plasticity related to grain boundary and precipitation strength effects.Consequently,the incorporation of 2 wt.%Dy into Mg-6 Zn alloys results in a synergistic enhancement of strength,as well as moderate corrosion resistance and fracture elongation.
基金supported by the Key Research and Development Program of Shanxi Province(202102130501007)the Natural Science Foundation of Shanxi Province(202403021212109,202203021211173)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(2024L039).
文摘Zinc(Zn)-based materials show broad application prospects for bone repair due to their biodegradability and good biocompatibility.In particular,Zn metal foam has unique interconnected pore structure that facilitates inward growth of new bone tissue,making it ideal candidates for orthopedic implants.However,pure Zn metal foam shows poor mechanical property,high degradation rate,and unsatisfactory osteogenic activity.Herein,Zinc-manganese(Zn-Mn)alloy foams were electrodeposited in Zn and Mn-containing electrolytes to overcome the concerns.The results showed that Mn could be incorporated into the foams in the form of MnZn_(13).Zn-Mn alloy foams showed better mechanical property and osteogenic activity as well as moderate degradation rate when compared with pure Zn metal foam.In addition,these properties could also be regulated by preparation process.The peak stress and osteogenic activity increased with deposition current(0.3‒0.5 A)and electrolyte pH(3‒5),but decreased with electrolyte temperature(20‒40℃),while the degradation rate exhibited opposite tendency,which suggests high deposition current and electrolyte pH and low electrolyte temperature can fabricate Zn-Mn alloy foam with favorable mechanical property,moderate degradation rate,and osteogenic activity.These findings provide a valuable reference for the design and fabrication of novel Zn-based biodegradable materials.
基金Funded by the National Natural Science Foundation of China(Nos.52171045,52162013,and 51932006)。
文摘The surface of MoSi2-SiB6/phenolic resin matrix composites was modified by mica,and the thermal oxidation behavior of the composites and the mechanical properties of the pyrolysis products were studied.The results showed that the mica improved the thermal properties of the composites,the thermal expansion coefficient decreased,and the liquid phase formation caused the composites to shrink and increase the density.The flexural strength of mica surface modified composites not only increased to 78.64MPa after thermal treatment at 800-1200℃,but reached 83.02 MPa after high temperature treatment at1400℃.The improvement of the mechanical properties of the residual product benefits from the formation of high temperature ceramic phases such as Mo_(2)C and MoB,and the improvement of the shear strength of the composites by the mica.The shear strength of MBm5-2 at room temperature reached 33.08 MPa,indicating that the improvement of the interlayer properties of the composites further improved its mechanical properties.
基金supported by the National Natural Science Foundation of China(Grant Nos.52074187 and 52274388)Liaoning Province Artificial Intelligence Innovation and Development Plan Project(Major Science and Technology Project)(2023JH26-10100002)the National Key Research and Development Program of China(No.2022YFB3304800).
文摘In order to solve the black-box modeling problem and improve the prediction accuracy of model,two distinguished models for tensile strength(Ts)and yield strength(Ys)of hot-rolled strip steel are established based on the industrial hot-rolled data and the algorithm of gene expression programming(GEP).Firstly,the industrial data of hot-rolled strip steel are preprocessed using the Pauta criterion,so as to eliminate outliers.The key input variables that affect Ys and Ts are selected by using the method of the maximal information coefficient(MIC).Secondly,the explicit prediction models of Ys and Ts are established using GEP.Subsequently,the model results based on GEP are compared with those based on the support vector regression(SVR)and the back propagation neural network(BPNN).Finally,the mathematical expression models for Ys and Ts obtained by GEP are used to further analyse the specific relationships between the chemical composition and mechanical property.It is shown that the errors of Ys and Ts based on GEP are less than 4%,and the coefficient of determination(R^(2))of Ys and Ts based on GEP is above 0.9,which has strong prediction performance.The prediction accuracy of GEP can achieve the same level with SVR and BPNN.It is worth mentioning that the proposed model can not only show the explicit relationship between the chemical composition,production process,and mechanical property of strip steel,but also occupy high prediction accuracy,which can make reliable reference for strip steel product design and optimisation.
文摘Correction to:J.Iron Steel Res.Int.https://doi.org/10.1007/s42243-025-01545-x The publication of this article unfortunately contained mistakes.Equation(14)was not correct.The corrected equation is given below.
基金Projects(50674038,50974048)supported by the National Natural Science Foundation of ChinaProject(200802140004)supported by Doctoral Fund of Ministry of Education of China
文摘Low temperature mechanical properties of AZ91D magnesium alloy fabricated by solid recycling process from recycled scraps were studied. Various microstructural analyses were performed using optical microscopy （OM） and scanning electron microscopy （SEM）. The recycled specimens consist of fine grains due to dynamic recrystallization and the interfaces of original individual scraps are not identified. Tensile tests were performed at a strain rate of 5 x 10 3 s 1 at room temperature （27 ~C）, -70, -100 and 130 ~C, respectively. Ultimate tensile strength of the specimens increases slightly with decreasing the tensile temperature, and elongation to failure decreases with decreasing the tensile temperature. The tensile specimens at -130 ~C show the highest ultimate tensile strength of 360.65 MPa and the lowest elongation to failure of 5.46%. Impact tests were performed at room temperature （27 ~C）, -70 and -130 ~C, respectively. Impact toughness decreases with decreasing the impact temperature. The impact specimens at -130 ~C show the lowest impact toughness of 3.06 J/cm2.
基金Projects(2010A090200078,2011A080403008)supported by the Major Science and Technology Project of Guangdong Province,China
文摘Microstructures and phase compositions of as-cast and extruded ZK60-xGd （x=0-4） alloys were investigated. Meanwhile, the tensile mechanical property was tested. With increasing the Gd content, as-cast microstructure is refined gradually. Mg-Zn-Gd new phase increases gradually, while MgZn2 phase decreases gradually to disappear. The second phase tends to distribute along grain boundary by continuous network. As-cast tensile mechanical property is reduced slightly at ambient temperature when the Gd content does not exceed 2.98%. After extrusion by extrusion ratio of 40 and extrusion temperature of 593 K, microstructure is refined further with decreasing the average grain size to 2 μm for ZK60-2.98Gd alloy. Broken second phase distributes along the extrusion direction by zonal shape. Extruded tensile mechanical property is enhanced significantly. Tensile strength values at 298 and 473 K increase gradually from 355 and 120 MPa for ZK60 alloy to 380 and 164 MPa for ZK60-2.98Gd alloy, respectively. Extruded tensile fractures exhibit a typical character of ductile fracture.
基金supported by National Key R&D Program of China(Grant No.2022YFB4600103)National Youth Talent Support Program,China Postdoctoral Science Foundation(Grant No.2021M692555)+1 种基金Shaanxi Province Qinchuangyuan'Scientists+Engineers'Team Building Project(Grant No.2023KXJ-266)Fundamental Research Funds for the Central Universities(Grant No.xzy012023145)。
文摘Multimaterial digital light processing(DLP)three-dimensional(3D)printing technology provides unique advantages in the field of multi material additive manufacturing(MM AM)with its high resolution and rapid shaping capabilities based on photopolymerization.However,owing to differences in the curing behavior and physical properties of different materials,multimaterial DLP 3D printing faces challenges such as insufficient interfacial bonding strength and unstable mechanical properties.In this study,two resins were integrated by multimaterial DLP 3D printing technology,and the effects of different layer thicknesses and exposure times on the interfacial bonding strength and morphology of the multimaterials were systematically investigated.The interfacial bonding mechanisms of the two resins was analyzed.It was found that increasing the exposure time can improve the interfacial bonding strength between materials,but certain limitations exist.A mathematical model relating the interfacial bonding strength to the exposure time and layer thickness was developed,and optimal process parameters were determined using optimization algorithms.A variable-parameter printing strategy for the interface was proposed to further improve the performance of printed parts.The maximum tensile strength of the multimaterial samples(44.43 MPa)using this strategy reached that of single-material parts(45 MPa),validating the feasibility of this strategy.This provides guidance for multimaterial DLP 3D printing processes and offers valuable insights for the future additive manufacturing of high-performance multimaterial components.
基金supported by the National Natural Science Foundation of China(No.52301041)the Guizhou Provincial Basic Research Program(No.QianKeHeJiChu-ZK[2024]YiBan036)+1 种基金the Special Fund for Special Posts of Guizhou University(No.[2023]26)the Fundamental Research Funds for the Central Universities.E.G.thanks support from Xiaomi Foundation.
文摘This study develops novel Mg-Sn-In-Ga alloys as potential implant materials for orthopedic applications.The corrosion behavior of the Mg-Sn-In-Ga alloys was studied through mass loss measurements,hydrogen evolution measurements,electrochemical analysis,and corrosion morphology observations.The results show that the corrosion rate of the Mg-1Sn-1In-1Ga alloy was only 0.10±0.003 mm/y after immersion in Hank’s solution for 15 days.This outstanding corrosion resistance was associated with the protective efect of the corrosion products.The increase in the Sn and Ga element content led to the precipitation of a large amount of Mg_(2)Sn and Mg_(5)Ga_(2),which had a dominant efect on the corrosion rate in the Mg-5Sn-1In-2Ga alloy.These precipitates increased the current density and detached from the alloy surface during the corrosion process.This can lead to a weakened protective efect of the corrosion layer,and thus generate localized corrosion and an increase in the corrosion rate.The strength of the Mg-5Sn-1In-2Ga alloy was enhanced due to fne-grain strengthening and precipitation strengthening.The ultimate tensile strength and yield strength of the Mg-5Sn-1In-2Ga alloy were~309 MPa and~253 MPa,respectively.
文摘The cold radial forging process usually introduces some changes of the material, such as the increased strength, the decreased plasticity and the introduction of anisotropic mechanical prop- erty. To obtain the changes of mechanical property of barrel processed by cold radial forging, the tangential mechanical properties of the barrel blank and the forged barrel are measured with a de- signed test based on the plastic deformation analysis for a barrel and by applying internal pressure, and their axial mechanical properties are measured by the tensile test. The changes of mechanical property of barrel processed by cold radial forging are obtained by comparing the mechanical proper- ties of the barrel blank and the forged barrel. The tangential and axial flow stresses of the barrel blank and the forged barrel are also presented.
文摘The effect of heat treatment on microstructure and mechanical properties of the Ti-steel explosive-rolling clad plate was elaborated by optical microscopy （OM）, scanning electron microscopy （SEM）, X-ray diffraction （XRD）, transmission electron microscopy （TEM）, micro-hardness test and shear test. The composites were subjected to heat treatment at temperature of 650-950 ~C for 60 min. The results show that the heat treatment process results in a great enhancement of diffusion and microstructural transformation. The shear strength decreases as the treatment temperature increases. Heated at 850 ℃ or below, their shear strength decreases slowly as a result of the formation of TiC in the diffusion interaction layer; while at the temperature of 850 ℃ or above, the shear strength decreases obviously, which is the consequence of a large amount of Ti-Fe intermetaUics （Fe2Ti/FeTi） along with some TiC distributing continuously at diffusion reaction layer.
基金Project(2013CB632202)supported by the National Basic Research Program of China
文摘The mixed grain structure and mechanical property anisotropy of AZ40 magnesium alloy bar with a diameter of 160 mm manufactured by ＂multi-direction forging（MDF） ＋ extrusion ＋ online cooling＂ technique were investigated by optical microscopy（OM）, scanning electron microscopy（SEM）, X-ray diffraction macro-texture measurement and room temperature（RT） tensile test. The results show that mixed grain structure is caused by the micro-segregation of Al in semi-continuous casting ingot. Homogenization of（380 °C, 8 h） ＋（410 °C, 12 h） cannot totally eliminate such micro-segregation. During MDF and extrusion, the dendrite interiors with 3%-4% Al（mass fraction） transform to fine grain zones, yet the dendrite edges with about 6% Al transform to coarse grain zones. XRD macro-textures of the outer, R/2 and center show typical fiber texture characteristics and the intensity of [0001]//Ra D orientation in the outer（11.245） is about twice as big as those in the R/2（6.026） and center（6.979）. The as-extruded AZ40 magnesium alloy bar has high elongation（A） and moderate ultimate tensile strength（Rm） in both extrusion direction（ED） and radius direction（Ra D）, i.e., A of 19%-25% and Rm of 256-264 MPa; however, yield strength（Rp0.2） shows anisotropy and heterogeneity, i.e., 103 MPa in Ra D, 137 MPa in ED-C（the center） and 161 MPa in ED-O（the outer）, which are mainly caused by the texture.（155 °C, 7 h） ＋（170 °C, 24 h） aging has no influence on strength and elongation of AZ40 magnesium bar.
基金Supported by the National Natural Science Foundation of China(No.51165032)the Innovative Group of Science and Technology of College of Jiangxi Province(No.00008713)
文摘The effects of addition of La on the microstructure of as-cast ADC12 A1-Alloy were investigated by using optical microscope （OM）, X-ray diffraction （XRD）, scanning electron microscope （SEM）, and energy disperse spectroscopy （EDS）. The experimental results showed that the a-A1 and eutectic Si crystals were modified with the addition of 0.3 wt% La. The eutectic Si crystals showed a granular distribution. At the same time, the alloy possessed the best mechanical property. When more than 0.3 wt% La was added to ADC12 aluminum alloy, the microstructure of as-cast alloy was coarsening gradually with the increase of the content of La and the mechanical property decreased. The effect of rare earth La which was added in ADC 12 A1-Alloy for up to 0.9 wt% had been investigated in this study. The dendrites ofADC12 Al-alloy was refined obviously and the morphology of Si crystals showed a particle structure when the addition of La reached 0,3 wt%. Besides, the acicular La-rich intermetallics in the alloy deteriorated the mechanical property of alloy： To avoid this unwanted phase, the amount of added rare earth La must be less than 0.6 wt%.
基金Projects (50801019, 51071062, 50771041) supported by the National Natural Science Foundation of ChinaProject (2011CB605504) supported by the National Basic Research Program of China
文摘Effect of thermal stabilization on the microstructure and mechanical property of directionally solidified Ti-46Al-0.5W-0.5Si （mole fraction, %） alloy was investigated. The specimens were thermal stabilized for different time （t） and directionally solidified at a constant growth rate of 30 μm/s and temperature gradient of 20 K/mm. Dependencies of the primary dendritic spacing （λ1）, secondary dendritic spacing （λ2）, interlamellar spacing （λL） and microhardness （HV） on holding time were determined. The values of the λ1, λ2 and λL increase with the increase of t, and the value of HV decreases with the increase of t. The increase of t is helpful to obtain a good directional solidification structure. However, it reduces the mechanical property of the directionally solidified TiAl alloy. The optimized value of t is about 30 min.
基金Projects (2010CB731700,2012CB619500) supported by the National Basic Research Program of China
文摘The influence of Li addition on mechanical property and aging precipitation behavior of Al-3.5Cu-1.5Mg alloy was investigated by tensile test,scanning electron microscopy（SEM）,transmission electron microscopy（TEM） and high resolution transmission electron microscopy（HRTEM）.The results show that the tensile strength can be significantly improved with the slightly decreased ductility and the form of fracture morphology is converted from ductile fracture into ductile/britde mixed fracture by adding 1.0%Li.Besides,the peak aging time at 185 ℃ is delayed from 12 to 24 h and the main precipitation phase S（Al2CuMg） is converted into S＇（Al2CuMg）＋δ（Al3Li）,while the formation of S＇（Al2CuMg） is delayed.
基金supported by National Key Research and De-velopment Program of China(No.2021YFB3701002)National Nat-ural Science Foundation of China(No.U2167213,51971053)+1 种基金and funded by the Project of Promoting Talents in Liaoning province(No.XLYC1808038).H.C.Pan acknowledges the financial assistance from Young Elite Scientists Sponsorship Program by CAST(2019-2021QNRC001,2019-2021QNRC002,2019-2021QNRC003)the fund from the Fundamental Research Funds for the Central Univer-sities(N2202020).
文摘Constructing bimodal grain structure is a promising approach to achieve the high strength-ductility syn-ergy in Mg alloy.Formation of bimodal grain is closely related to the dynamic and/or static recrystal-lization process,which has not been fully understood in the typical Mg-RE based alloy.In this work,it is claimed for the first time that the minor Ce addition(∼0.3 wt%)into Mg matrix significantly pro-motes the pyramidal<c+a>and non-basal<a>dislocations at the early stage of extrusion,which con-sequently enhances the formation of sub-grain boundaries via the movement and recovery of pyramidal II-type<c+a>dislocations.At this stage,fine sub-grain lamellae are widely observed predominantly due to the low migration rate of sub-grain boundary caused by the limited mobility of<c+a>dislocations.At the later stage,the sub-grains continuously transform into dynamic recrystallized(DRXed)grains that have10¯10Taylor axis and also strong fiber texture,indicating substantial activation of pyramidal II-type<c+a>dislocation.The low mobility of<c+a>dislocations,accompanied with the solute drag from grain boundary(GB)segregation and pinning from nano-phases,cause a sluggish DRX process and thus a bimodal microstructure with ultra-fined DRXed grains,∼0.51μm.The resultant texture hardening and grain refinement hardening effects,originated from bimodal microstructure,result in a yield strength of∼352 MPa,which is exceptional in Mg-Ce dilute alloy.This work clarifies the critical role of Ce addition in tuning recrystallization behavior and mechanical property of magnesium,and can also shed light on designing the other high-performance Mg alloys.
基金Natural Science Foundation of Anhui Provincial Education Depart ment of China (2006KJ080A)
文摘Mechanical property prediction of hot rolled strip is one of the hotspots in material processing research. To avoid the local infinitesimal defect and slow constringency in pure BP algorithm, a kind of global optimization algorithm-particle swarm optimization （PSO） is adopted. The algorithm is combined with the BP rapid training algorithm, and then, a kind of new neural network （NN） called PSO-BP NN is established. With the advantages of global optimization ability and the rapid constringency of the BP rapid training algorithm, the new algorithm fully shows the ability of nonlinear approach of multilayer feedforward network, improves the performance of NN, and provides a favorable basis for further online application of a comprehensive model.
