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Simultaneous measurement of thermal conductivity, heat capacity, and interfacial thermal conductance by leveraging negative delay-time data in time-domain thermoreflectance

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Progress in Natural science:Materials International 2025年第2期35卷 375-384页

作者： Mingzhen Zhang Tao Chen Ao Zeng Jialin Tang Ruiqiang Guo Puqing Jiang School of Energy and Power Engineering Huazhong University of Science and Technology Thermal Science Research Center Shandong Institute of Advanced Technology Institute of Advanced Technology Shandong University

Time-domain thermoreflectance（TDTR） is a widely used technique for characterizing the thermal properties of bulk and thin-film materials. Traditional TDTR analyses typically focus on positive delay time data for fitting,often requiring multiple-frequency measurements to simultaneously determine thermal conductivity and heat capacity. However, this multiple-frequency approach is cumbersome and may introduce potential errors due to practical challenges to ensure consistent measurements across different frequencies. In this study, we propose a novel solution to these challenges by harnessing the underexplored negative delay time data in TDTR. By integrating these data points, we offer a streamlined, single-frequency method that simultaneously measures thermal conductivity, heat capacity, and interfacial thermal conductance for both bulk and thin-film materials, enhancing measurement efficiency and accuracy. We demonstrate the effectiveness of this method by measuring several bulk samples including sapphire, silicon, diamond, and Si0.992Ge0.008, and several thin-film samples including a 1.76-μm-thick gallium nitride（Ga N） film epitaxially grown on a silicon substrate, a 320-nm-thick gallium oxide（ε-Ga2O3） film epitaxially grown on a silicon carbide substrate, and a 330-nm-thick tantalum nitride（Ta N） film deposited on a sapphire substrate, all coated with an aluminum（Al） transducer layer on the surface. Our results show that the new method accurately determines the thermal conductivity and heat capacity of these samples as well as the Al/sample interfacial thermal conductance using a single modulation frequency, except for the Si0.992Ge0.008sample. This study sheds light on the untapped potential of TDTR, offering a new, efficient, and accurate avenue for thermal analysis in material science.

关键词： Heat capacity Negative delay time TDTR Thermal conductivity Time-domain thermoreflectance

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Microstructure evolution and strengthening mechanism of high -performance powder metallurgy TA15 titanium alloy by hot rolling

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1426-1436页

作者： Ying Gao Ce Zhang Jiazhen Zhang Xin Lu Beijing Advanced Innovation Center for Materials Genome Engineering State Key Laboratory for Advanced Metals and MaterialsInstitute for Advanced Ma-terials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China National Engineering Research Center for Advanced Rolling Technology National Engineering Research Center for Flat Rolling EquipmentInstitute of Engin-eering TechnologyUniversity of Science and Technology BeijingBeijing 100083China

Hot deformation of sintered billets by powder metallurgy(PM)is an effective preparation technique for titanium alloys,which is more significant for high-alloying *** this study,Ti–6.5Al–2Zr–Mo–V(TA15)titanium alloy plates were prepared by cold press-ing sintering combined with high-temperature hot *** microstructure and mechanical properties under different process paramet-ers were *** microscope,electron backscatter diffraction,and others were applied to characterize the microstructure evolution and mechanical properties strengthening *** results showed that the chemical compositions were uniformly dif-fused without segregation during sintering,and the closing of the matrix craters was accelerated by increasing the sintering *** block was hot rolled at 1200℃ with an 80%reduction under only two passes without *** strength and elongation of the plate at 20–25℃ after solution and aging were 1247 MPa and 14.0%,respectively,which were increased by 24.5%and 40.0%,respect-ively,compared with the as-sintered alloy at 1300℃.The microstructure was significantly refined by continuous dynamic recrystalliza-tion,which was completed by the rotation and dislocation absorption of the substructure surrounded by low-angle grain *** hot rolling combined with heat treatment,the strength and plasticity of PM-TA15 were significantly improved,which resulted from the dense,uniform,and fine recrystallization structure and the synergistic effect of multiple slip systems.

关键词： elemental powder powder metallurgy titanium alloy hot rolling strength and plasticity

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Effect of post rolling stress on phase transformation behavior of microalloyed dual phase steel

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Journal of Iron and Steel research International 2024年第3期31卷 688-699页

作者： Wen-quan Sun Sheng-yi Yong Tie-heng Yuan Ting-song Yang An-rui He Chao Liu Rui-chun Guo National Engineering Research Center for Advanced Rolling and Intelligent Manufacturing University of Science and Technology BeijingBeijing 100083China

The slow phase transformation of microalloyed dual phase steel makes the nonuniform stress and temperature fields during the post rolling cooling process have a significant impact on the phase transformation *** the relatively slow phase transformation of DP780 steel within the microalloyed dual phase steel series,the influence of stress on the phase transformation behavior of DP780 steel was *** quantify the nonuniform thermal and stress conditions in the steel coil,a thermo-mechanical coupled finite element model of the hot-rolled strip cooling process was *** on the simulation data,DP780 steel was chosen as the research material,and Gleeble 3500 thermal simulation equipment was used for experimental *** thermal expansion curves were analyzed through regression to establish the dynamic model of DP780 steel phase transformation under ***,metallographic analysis was conducted to determine phase transformation type and grain size of DP780 *** results confirmed that the stress promotes the occurrence of semi-diffusion-type bainite ***,an appropriate level of stress facilitates the growth of bainitic grains,while the increased stress inhibits the growth of ferritic grains.

关键词： Microalloyed dual phase steel Stress Bainitic transformation Grain Finite element method

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Effects of longitudinal magnetic field on primary dendrite spacing and segregation of directionally solidified single crystal superalloy

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Progress in Natural science:Materials International 2024年第1期34卷 26-36页

作者： Congjiang Zhang Yilin Zhou Chen Shen Weili Ren Xiaotan Yuan Biao Ding Haibiao Lu Zuosheng Lei Yunbo Zhong Ang Zhang State Key Laboratory of Advanced Special Steel College of Materials Science and Engineering Shanghai University National Engineering Research Center for Magnesium Alloys Natural Key Laboratory of Advanced Casting Technologies College of Materials Science and EngineeringChongqing University

The primary dendrite spacing(PDS) and segregation of directionally solidified single crystal(SC) superalloy under the longitudinal magnetic field(LMF) were investigated based on the analysis of the whole cross-sectional microstructure at different solidification distances. The results show that the PDS under the LMF remains basically unchanged at different solidification distances, and it is greater than that under no LMF. With the increase of magnetic field intensity, the PDS increases and the macrosegregation decreases. The increasing PDS and reducing segregation under the LMF can be attributed to the increase of solute boundary layer, which expands the non-equilibrium freezing temperature range and brings the effective partition coefficient closer to 1. The increase of the solute enrichment layer thickness could be caused by the downward secondary circulation generated by the thermoelectric magnetic convection(TEMC) near the interface, which drives the migration of solutes towards the interdendritic region. This work not only clarifies the mechanism of LMF controlling PDS and reducing segregation by TEMC, but also provides theoretical guidance for producing high-quality SC superalloys using magnetic fields.

关键词： Primary dendrite spacing Segregation Single crystal superalloy Directional solidification Magnetic field Thermoelectric magnetic convection

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Compositional tuning of A_(2)B_(7)-type La_(0.7-x)Y_(x)Mg_(0.3)Ni_(3.5)alloys for gaseous hydrogen storage

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Journal of Rare Earths 2024年第10期42卷 1912-1919页

作者： Junkun Du Hui Wang Renheng Tang Jiangwen Liu Liuzhang Ouyang Min Zhu School of Materials Science and Engineering Guangdong Engineering Technology Research Center of Advanced Energy Storage MaterialsSouth China Universityof TechnologyGuangzhou510640China

Rare earth-based superlattice alloys have great potential for gaseous hydrogen storage,as well as successful application as nickel-metal hydride batteries *** this work,Y substitution was carried out to adjust the gaseous hydrogen storage properties of A_(2)B_(7)-type La_(0.7)Mg_(0.3)Ni_(3.5)*** results indicate a multiphase structure in the alloys comprised of the main rhombohedral Gd_(2)Co_(7)and PuNi_(3)phases,with a small amount of CaCu_(5)***,the Y substitution results in higher abundance of the Gd_(2)Co_(7)*** alloy La_(0.42)Y_(0.28)Mg_(0.3)Ni_(3.5)exhibits a hydrogen storage cap acity of 1.55 wt%at 298 K and a desorption plateau pressure of 0.244 *** addition,this alloy demonstrates a stable cycle life by a capacity retention of 94.2%after 50 cycles,with the main capacity degradation occurring during the initial 20 *** work accentuates the potential of the La-Y-Mg-Ni-based superlattice alloys for applications in solid-state hydrogen storage.

关键词： Hydrogen storage A_(2)B_(7)-type La-Mg-Ni alloys Y substitution Desorption plateau pressure Cycle performance Rare earths

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Constructing metal-phenolic network(MPN)microspheres as efficient adsorbent for pollutants removal

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Particuology 2025年第3期98卷 241-248页

作者： Qiang Liu Lin Han Tiantian Feng Ying Li Tao Jiang Jian Li Lanzhou Petrochemical Research Center Petrochemical Research InstitutePetroChinaLanzhou730060China Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical TechnologyBeijing100029China College of Chemical Engineering and Materials Science Tianjin University of Science and TechnologyTianjin300457China

Metal-phenolic networks(MPNs)are a versatile class of self-assembled systems that are generating interest for applications in catalysis,bioimaging,and drug *** contrast to traditional MPNs coating,in this research,we fabricated novel MPNs microspheres through a facile process in the aqueous *** MPNs microspheres are characterized by SEM,TEM,and *** as-prepared microspheres were utilized in the removal of tetracycline(TC),methylene blue(MB),and rhodamine B(RhB).It exhibits high capacity(1331 mg/g)for the adsorption of MB,and a rapid reaction rate(186.9 mg/g/min)for the adsorption of TC.

关键词： Metal-phenolic network(MPN) Self-assembly Microspheres Adsorption Pollutants removal

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Tuning mechanical and electrical performances of B_(4)C-TiB_(2)ceramics in a two-step spark plasma sintering process

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Journal of advanced Ceramics 2024年第4期13卷 518-528页

作者： Jun Zhao Xingshuo Zhang Zongning Ma Dong Wang Xing Jin Songlin Ran Advanced Ceramics Research Center School of Materials Science and EngineeringAnhui University of TechnologyMaanshan 243002China Anhui Engineering Research Center for High Efficiency Intelligent Photovoltaic Module Chaohu UniversityHefei 238024China

B_(4)C–TiB_(2)is an advanced electrically conductive ceramic with excellent mechanical and electrical discharge machinable *** is challenging and rewarding to achieve highly conductive and hard B_(4)C–TiB_(2)composites at a minimum content of conductive TiB2 that has inferior hardness but double specific gravity of the B_(4)C matrix.A novel strategy was used to construct conductive networks in B_(4)C‒15 vol%TiB2 composite ceramics with B_(4)C,TiC,and amorphous B as raw materials by a two-step spark plasma sintering *** influences of particle size matching between B_(4)C and TiC on the conducting of the strategy and the microstructure were discussed based on the selective matrix grain growth *** mechanical and electrical properties were also systematically *** B_(4)C–15 vol%TiB2 composite ceramic prepared from 10.29µm B_(4)C and 0.05µm TiC powders exhibited a perfect three-dimensional interconnected conductive network with a maximum electrical conductivity of 4.25×10^(4)S/m,together with excellent mechanical properties including flexural strength,Vickers hardness,and fracture toughness of 691±58 MPa,30.30±0.61 GPa,and 5.75±0.32 MPa·m^(1/2),respectively,while the composite obtained from 3.12µm B_(4)C and 0.8µm TiC powders had the best mechanical properties including flexural strength,Vickers hardness,and fracture toughness of 827±35 MPa,32.01±0.51 GPa,and 6.45±0.22 MPa·m^(1/2),together with a decent electrical conductivity of 0.65×10^(4)S/m.

关键词： B_(4)C-TiB_(2) mechanical properties electrical conductivity conductive network

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Segregation of Mg-6Gd alloy under natural convection:From macro solute distribution to micro dendrite growth

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China Foundry 2024年第5期21卷 613-624页

作者： Hong-xu Chen Ang Zhang Hao Li Yu Gao Yu-hong Cui Guang-sheng Huang Bin Jiang Fu-sheng Pan National Engineering Research Center for Magnesium Alloys National Key Laboratory of Advanced Casting TechnologiesCollege of Materials Science and EngineeringChongqing UniversityChongqing 400044China

Segregation is a serious defect in alloy ingots which severely deteriorates materials *** segregation defect in Mg-6Gd alloy is studied by coupling macro thermal-solutal-convection transport and micro dendrite *** macroscopic fluid dynamics and mass transfer equations are resolved to forecast the segregation behavior under conditions of continuous temperature variation during the solidification *** numerical model is validated by testing double-diffusive natural convection in a closed square cavity.A phase field model is then applied to simulate the micro dendrite growth,using macro undercooling and liquid flow velocity as boundary *** show that the multiscale segregation behavior,including macro solute distribution and micro dendritic morphology,is strongly dependent on the temperature condition and the liquid convection,which provides guidance for reducing and eliminating the segregation defect.

关键词： magnesium alloy segregation numerical simulation phase-field simulation multiscale

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Unveiling the homogenization microstructure evolution and its effect on cellular structure for Fe-rich Sm-Co-Fe-Cu-Zr magnets

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Journal of Materials science & Technology 2024年第27期194卷 142-150页

作者： Qiangfeng Li Chao Wang Lei Wang Yifei Bi Yikun Fang Yue Zhang Minggang Zhu Wei Li Division of Functional Materials Central Iron and Steel Research InstituteBeijing 100081China Academy for Advanced Interdisciplinary Science and Technology Beijing Advanced Innovation Center for Materials Genome Engineering and Beijing Key Laboratory for Advanced Energy Materials and TechnologiesSchool of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083China

The solution-treated Fe-rich 2:17-type Sm-Co-based magnets generally contain an inhomogeneous mi-crostructure,which hinders the development of the complete cellular structure required for high-performance ***,the microstructure evolution of Sm(Cobal Fe_(0.31)Cu_(0.07)Zr_(0.025))_(7.7)magnet during the solution treatment is systematically *** the normal Fe-medium magnets,it was in-terestingly found that the initial-stage solution-treated Sm(Cobal Fe_(0.31)Cu_(0.07)Zr_(0.025))_(7.7)magnet possesses a profuse lamellar-type *** the lamellar-type microstructure,there are three microre-gions exhibiting an obvious difference in composition and 2:17R ordering ***,various 1:3R phases precipitated within the lamellar-type *** the disappearance of lamellar-type mi-crostructure,the 1:7H phase increased substantially,and the distribution of defect-aggregated cell bound-aries became uniform,promoting the homogeneous precipitation of 1:5H cell boundary phases during *** current study reveals a typical microstructural evolution in Fe-rich 2:17-type Sm-Co-based magnets during solution treatment.

关键词： Sm_(2)Co_(17)magnet Supersaturated solid solution Phase transformation TEM

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Enhanced strength and ductility in a powder metallurgy Ti material by the oxygen scavenger of CaB_(6)

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Journal of Materials science & Technology 2023年第6期137卷 132-142页

作者： Yu Pan Jinshan Zhang Jianzhuo Sun Yanjun Liu Ce Zhang Rui Li Fan Kuang Xinxin Wu Xin Lu Beijing Advanced Innovation Center for Materials Genome Engineering Institute of Engineering TechnologyNational Engineering Research Center for Advanced Rolling TechnologyUniversity of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering Nanjing Institute of TechnologyNanjing 211167China

The challenge of producing a high-ductility titanium(Ti)material using inexpensive high-oxygen hydride-dehydride(HDH)Ti powder is hereby addressed by the incorporation of CaB_(6)*** oxygen-scavenging behavior,microstructure evolution,mechanical behavior and improvement mechanism were systematically investigated.A continuous TiO_(2)oxide layer with a thickness of approximately 9.3 nm is presented on the HDH Ti powder *** oxide layer will dissolve into Ti matrix during sintering,making the increase of c/a value and leading to the Ti-Ti bonds developing from plastic metal bonds to-ward brittle covalent *** CaB_(6)addition can scavenge O impurity and make a significant increase in tensile ductility forα-Ti matrix.A small addition of 0.2 wt.%CaB_(6)provides a superior tensile elongation of 22.2%for Ti material,almost three times as high as that of pure Ti(7.5%).The increase of defor-mation twining activity and grain refinement are responsible for the improved ***,the CaB_(6)oxygen-scavenger can react with the surface oxide layer to in-situ form rod-like TiB and granular CaTiO_(3)reinforcements,refining the coarse near equiaxed grain ofα-Ti matrix into fine equiaxed *** multiple mechanisms of grain-boundary strengthening,load-bearing strengthening of TiB and Orowan strengthening of CaTiO_(3)nanoparticles work together to increase the tensile strength of Ti/CaB_(6)*** work offers an effective method to fabricate high-performance Ti material using inex-pensive high-oxygen HDH Ti powder.

关键词： Titanium Powder metallurgy Sintering Oxygen Mechanical properties

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