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Viscosity in metallic supercooled liquids obtained by fast scanning calorimetry and its application to thermoplastic forming

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Science China(Physics,Mechanics & Astronomy) 2025年第6期68卷 23-32页

作者： Min Liu Zheng Wang Yijun Ding Senkuan Meng Lina Hu Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinan 250061China

Viscosity is a crucial dynamic property for alloy *** alloy liquids with glass-forming ability,their viscosity undergoes a change of more than ten orders of magnitude upon cooling,and eventually,a transition from liquid to glassy state occurs when viscosity reaches 1012 Pa ***,the viscosity measurement in the supercooled liquid region(SLR)has been an experimental ***,in this work,by combining conventional and fast scanning calorimeters,the accurate viscosity of supercooled liquids for Au_(49)Ag_(5.5)Pd_(2.3)Cu_(26.9)Si_(16.3) and Zr_(44)Ti_(11)Cu_(10)Ni_(10)Be_(25) metallic glasses(MGs)was measured over a wide viscosity range of 10^(6)-10^(12) Pa ***,the viscosity range of 10^(6)-10^(8) Pa s is generally selected for thermoplastic forming(TPF),which takes advantage of the dramatic softening that MGs exhibit after being heated into the *** further gave the TPF process window covering the range of processing temperature and time by utilizing the obtained viscosity data and timetemperature-transformation *** optimal time window avoiding property degradation was also determined,based on that there was no marked effect on the mechanical properties of MGs when crystallinity was below~5%.Our findings not only provide the accurate viscosity data in the SLR,but also determine the optimal process parameters for the TPF process.

关键词： metallic glass viscosity supercooled liquid thermoplastic forming fast scanning calorimetry

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Nanoscale analysis of interfacial structure and its effects on mechanical properties of Mg/Al laminate reinforced by TiB_(2) particles

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Journal of Magnesium and Alloys 2025年第3期13卷 1310-1324页

作者： Lihua Qian Liang Chen Biaohua Que Kaiqiang Shen Guoqun Zhao Cunsheng Zhang Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinanShandong 250061PR China

Fabricating Mg/Al laminate is an effective strategy to circumvent the inherently low formability and poor corrosion resistance of Mg ***,Mg/Al laminate with good bonding quality and mechanical properties was successfully fabricated via porthole die co-extrusion process using ZK60 Mg and TiB_(2)/6061Al composite as constituted *** the results from microstructural characterization and mechanical testing,the effects of extrusion temperature on microstructure,interfacial structure,element diffusion,and mechanical properties were *** results show that Mg/Al laminate achieves a sound welding quality by mechanical bonding and diffusion *** obvious intermetallic compounds(βandγ)layer forms at Mg/Al interface,and its thickness increases to 8.3μm as the extrusion temperature reaches 400℃.High extrusion temperature promotes the dynamic recrystallization and grain growth of Mg and Al layers,while the dislocation density decreases.β/γinterface shows a coherent feature,whileγ/Mg interface is semi-coherent with a locally ordered transition zone of 4.5 *** rich Mg and Cr layers are found at TiB_(2)/6061 interface,which is conducive to improving the bonding *** the extrusion temperature is 370℃,the thickness of diffusion layer is around 5.0μm,and the bonding strength reaches 18.68 MPa,resulting in the best comprehensive mechanical *** work provides a new direction for the development of Mg/Al laminate with excellent strength and ductility.

关键词： Mg/Al Extrusion Microstructure Interface Dislocation density

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Construction of an Arrhenius constitutive model for Mg-Y-Nd-Zr-Gd rare earth magnesium alloy based on the Zener-Hollomon parameter and objective evaluation of its accuracy in the twinning-rich intervals

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Journal of Magnesium and Alloys 2024年第7期12卷 2890-2908页

作者： Luyi Han Xiangjian Zhu Dejin Wei Yanan Yu Guangchun Wang Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinanShandong 250061PR China

According to a high-temperature compression test of rare earth magnesium alloy(WE43),a strain-compensated constitutive model of the Arrhenius equation based on Zener-Hollomon parameters was established,and the rheological behaviors were *** model exhibited relatively serious prediction distortion in the low-temperature and high-strain rate parameter interval,and its accuracy was still unsatisfactory even after modification by a correction operator considering the coupling of temperature and strain *** microstructure characterization and statistical analysis showed that a large number of twinning occurred in the parameter intervals with prediction *** occurrence of twinning complicated the local internal stress distribution by drastically changing the crystal orientation and led to significant fluctuations in the macroscopic strain-stress and hardening curves relative to the rheological processes dominated by the dislocation and softening mechanisms,making the logarithm of the strain rate and stress deviate from the linear *** twinning phenomenon was greatly influenced by the temperature and strain ***,the influence mechanism on twinning behavior was analyzed from the perspective of the interaction of dislocation and twinning.

关键词： RE magnesium alloy Hot deformation Zener-Hollomon parameters Arrhenius constitutive model Dislocation Twinning

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Elucidating the process mechanism in Mg-to-Al friction stir lap welding enhanced by ultrasonic vibration

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Journal of Magnesium and Alloys 2025年第1期13卷 338-355页

作者： Ming Zhai Lei Shi ChuanSong Wu MOE Key Lab for Liquid-Solid Structure Evolution and Materials Processing Institute of Materials JoiningShandong UniversityJinan 250061 China

The composite structures/components made by friction stir lap welding(FSLW)of Mg alloy sheet and Al alloy sheet are of wide application potentials in the manufacturing sector of transportation *** further improve the joint quality,the ultrasonic vibration(UV)is exerted in FSLW,and the UV enhanced FSLW(UVeFSLW)was developed for making Mg-to-Al dissimilar *** numerical analysis and experimental investigation were combined to study the process mechanism in Mg/Al *** equation related to the temperature and strain rate was derived to calculate the grain size at different locations of the weld nugget zone,and the effect of grain size distribution on the threshold thermal stress was included,so that the prediction accuracy of flow stress was further *** such modified constitutive equation,the numerical simulation was conducted to compare the heat generation,temperature profiles and material flow behaviors in Mg/Al UVeFSLW/FSLW *** was found that the exerted UV decreased the temperature at two checking points on the tool/workpiece interface from 707/671 K in FSLW to 689/660 K in UVeFSLW,which suppressed the IMCs thickness at Mg-Al interface from 1.7μm in FSLW to 1.1μm in *** exerted UV increased the horizontal materials flow ability,and decreased the upward flow ability,which resulted in the increase of effective sheet thickness/effective lap width from 2.01/3.70 mm in FSLW to 2.04/4.84 mm in ***,the ultrasonic vibration improved the tensile shear strength of Mg-to-Al lap joints by 18%.

关键词： Friction stir lap welding Mg-to-Al dissimilar alloys Ultrasonic vibration Numerical simulation Experimental investigation

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Intermetallic Compounds Formation in Dissimilar Friction Stir Welding of Mg/Cu Alloys

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Acta Metallurgica Sinica(English Letters) 2024年第9期37卷 1523-1532页

作者： Xue Li Qingzhen Zhao Hao Su Ji Chen Chuansong Wu MOE Key Lab for Liquid-Solid Structure Evolution and Materials Processing Institute of Materials JoiningShandong UniversityJinan250061China

Joining dissimilar Mg/Cu alloys was still an intractable problem because of the excessive intermetallic compounds(IMCs)and poor mechanical properties using conventional welding *** the present study,friction stir welding was employed for the butt joining of dissimilar AZ31B Mg-alloy and T2 pure Cu ***-free Mg/Cu joints were obtained with Mg-RS and Cu-AS configuration,at a welding speed of 50 mm/min and tool rotating speeds of 325 r/min,625 r/min and 925 r/*** the joining interface,both Mg_(2)Cu and MgCu_(2) IMC phases were observed,with a clear,uniform and continuous IMCs layer composed of two sub-layers,layer-A of Mg+Mg_(2)Cu and layer-B of Mg_(2)Cu+MgCu_(2).The maximum ultimate tensile strength of the Mg/Cu friction stir welding joint reached 130 MPa at 925 r/min due to enhanced mechanical interlocking between Mg and Cu,as well as sufficient metallurgical bonding at the joining interface with an IMCs layer thickness in the range of 1.0-2.0μm.

关键词： Friction stir welding Magnesium Copper Intermetallic compounds Mechanical properties

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Highly efficient broadband near-infrared luminescence phosphors Ca3MgSn0.5Zr0.5Ge3O12:Pr3+,Cr3+ for multifunctional applications in pc-LEDs field

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Journal of Rare Earths 2025年第6期43卷 1110-1119页

作者： Xiaole Xing Shanshan Huang Yining Wang Lingkang Yu Yixin Sun Mengmeng Shang Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education) School of Materials Science and EngineeringShandong University School of Chemistry and Pharmaceutical Engineering Huanghuai University

Exploring high-performance broadband near-infrared（NIR） emitting materials is crucial for the development of NIR *** this study,Ca3MgSn0.5Zr0.5Ge3O12:Cr3+and rare earth ion Pr3+co-doped Ca3MgSn0.5Zr0.5Ge3O12:Pr3+,Cr3+phosphors were successfully *** utilizing time-resolved emission spectroscopy（TRES）,photo luminescence（PL） spectra,and fluorescence decay curve,the Ca3MgSn0.5Zr0.5Ge3O12:Cr3+phosphor is determined to exhibit a broadband emission（650-1150 nm）with a peak at 795 nm due to Cr3+occupying multiple cationic sites,Ca3MgSn0.5Zr0.5Ge3O12:0.1Cr3+has excellent thermal stability（86%@425 K）,and co-doping Pr3+ions into Ca3MgSn0.5Zr0.5Ge3O12:0.1Cr3+obtains highly efficient NIR *** Ca3MgSn0.5Zr0.5Ge3O12:0.01 Pr3+,0.1 Cr3+phosphor has quantum yield of 89.4% thanks to the energy transfer effect from Pr3+to Cr3+.The fabricated NIR phosphorconverted light emitting diode（pc-LED） by integrating the blue chip with Ca3MgSn0.5Zr0.5Ge3O12:0.01 Pr3+,0.1Cr3+has diverse applications including night vision,non-destructive testing,and medical imaging.

关键词： Ca3MgSn0.5Zr0.5Ge3O12:Cr3+ Co-doping Pr3+ Energy transfer Multi-site occupation NIR emission Rare earths

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Magneto-volume effect in Fe_(n)Ti_(13-n)clusters during thermal expansion

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Chinese Physics B 2023年第4期32卷 78-86页

作者：黄建蒋妍彦李志超张迪钱俊平李辉 Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of EducationShandong UniversityJinan 250061China

Ab initio molecular dynamics calculations have been carried out to search for the ground state structure of Fe_(n)Ti_(13-n)clusters and measure the thermal expansion of Fe_(n)Ti_(13-n).The volume of Fe_(n)Ti_(13-n)clusters during thermal expansion is jointly determined by anharmonic interaction and magneto-volume *** has been found that Fe_(6)Ti_(7),Fe_9Ti_(4),Fe_(11)Ti_(2),and Fe_(13)clusters can exhibit the remarkable magneto-volume effect with abnormal volume behaviors and magnetic moment behaviors during thermal expansion.A prerequisite for the magneto-volume effect of Fe_(n)Ti_(13-n)clusters during thermal expansion has been revealed and the magnitude of the magneto-volume is also approximately ***,the magneto-volume behaviors of Fe_(n)Ti_(13-n)clusters are qualitatively characterized by the energy contour *** results shed light on the mechanism of the magneto-volume effect in Fe_(n)Ti_(13-n)clusters during thermal expansion,which can guide the design of nanomaterials with zero expansion or even controllable expansion properties.

关键词： Fe_(n)Ti_(13-n)cluster thermal expansion magneto-volume effect magnetic moment

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Suppressing abnormal grain growth and switching precipitation behaviors in ZK60 Mg profile by inducing pre-tension

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Journal of materials Science & Technology 2023年第24期155卷 89-101页

作者： Jianwei Tang Liang Chen Zhigang Li Biaohua Que Guoqun Zhao Cunsheng Zhang Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinan 250061China

The pre-tension was induced to suppress the abnormal grain growth(AGG)of ZK60 Mg profile during solution *** effects of pre-tension on the microstructure evolution and mechanical properties were studied,and the suppressing mechanism was *** the pre-tension strain was larger than 10%,AGG during solution could be effectively inhibited,resulting in a sharp decrease in the grain *** suppression effects were realized by restricting the orientation dependent of AGG and promoting static *** pre-tension reset the distributions of stored energy and sizes of the grains with〈11–20〉and〈10–10〉orientations,and thus retarded the orientation dependent of ***,the pre-tension introduced a mass of dislocations,twins,and stacking faults,all of which promoted the occurrence of static recrystallization,and the grain structure was further *** pre-tension accelerated the precipitation kinetics during aging,resulting in fine and dense *** the increase of pre-tension strain,the strength of ZK60 Mg profile monotonically increased.

关键词： Mg alloy Abnormal grain growth Pre-tension Microstructure Mechanical properties

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Experimental study on tensile deformation behaviors under room and elevated temperatures induced by microstructure inhomogeneity of ZK60 Mg with a longitudinal weld

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Journal of Magnesium and Alloys 2023年第11期11卷 4338-4356页

作者： Jianwei Tang Liang Chen Guoqun Zhao Cunsheng Zhang Lu Sun Junquan Yu Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinanShandong 250061China

The tensile tests of the extruded ZK60 Mg containing a longitudinal weld seam were carried out at room and elevated temperatures, and the effects of induced microstructure inhomogeneity on tensile deformation behavior was clarified. The results show that the deformation mode, dynamic recrystallization(DRX), texture evolution and mechanical properties are strongly affected by the longitudinal weld seam,temperature, and loading direction. The room temperature(RT) deformation of welding zone is controlled by the dislocation slips with the association of some twins, while twinning plays significant roles in the accommodation of c-axis strain of the coarse grains on matrix *** deformation at RT stretched along extrusion direction(ED) and transverse direction(TD) are controlled by basal slip/twinning and basal slip/prismatic slip/twinning, respectively. During high temperature tension, the dislocation cross slip of pyramidal slip is activated, and grain boundary sliding occurred in welding zone, leading to the superplastic behavior. With the increase of tensile temperature, the predominant DRX mode is transformed from continuous DRX to discontinuous DRX. Moreover, the basal poles of the grains spread from TD towards ED with the decrease of maximum pole intensity when stretched along ED, while non-basal textures are transformed to (10-10) fiber texture when stretched along TD. The slip-dominated flow is seen during RT tension along ED, while twinning becomes predominant during RT tension along TD. The fine grain structure causes the superior RT tensile properties along ED of welding zone with ultimate tensile strength of 315 MPa and elongation to failure of 13.8%. With the increase of tensile temperature, the slipping-dominated deformation is transformed into twinning-dominated, causing the decrease of strength and increase of elongation.

关键词： Inhomogeneous microstructure Tensile deformation Dynamic recrystallization Texture

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Activated carbon induced oxygen vacancies-engineered nickel ferrite with enhanced conductivity for supercapacitor application

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Frontiers of Chemical Science and Engineering 2023年第12期17卷 2088-2100页

作者： Xicheng Gao Jianqiang Bi Linjie Meng Lulin Xie Chen Liu Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) School of Materials Science and EngineeringShandong UniversityJinan 250061China

NiFe_(2)O_(4) is a kind of bimetallic oxide possessing excellent theoretical capacity and application prospect in the field of ***,due to the inherent poor conductivity of metal oxides,the performance of NiFe_(2)O_(4) is not ideal in *** vacancies can not only enhance the conductivities of NiFe_(2)O_(4) but also provide better adsorption of OH,which is beneficial to the electrochemical ***,oxygen vacancies engineered NiFe_(2)O_(4)(NiFe_(2)O_(4)‒δ)is obtained through a two-step method,including a hydrothermal reaction and a further heat treatment in activated carbon *** of electron paramagnetic resonance spectra indicate that more oxygen vacancies exist in the treated NiFe_(2)O_(4)‒δthan the original ***-Vis diffuse reflectance spectra prove that the treated NiFe_(2)O_(4)‒δowns better conductivity than the original NiFe_(2)O_(4).As for the electrochemical performances,the treated NiFe_(2)O_(4)‒δperforms a high specific capacitance of 808.02 F∙g^(‒1) at 1 A∙g^(‒1).Moreover,the asymmetric supercapacitor of NiFe_(2)O_(4)‒δ//active carbon displays a high energy density of 17.7 Wh∙kg^(‒1) at the power density of 375 W∙kg^(‒1).This work gives an effective way to improve the conductivity of metal oxides,which is beneficial to the application of metal oxides in supercapacitors.

关键词： nickel ferrite oxygen vacancy high conductivity supercapacitor

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