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Planar bi-metallic lattice with tailorable coefficient of thermal expansion

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Acta Mechanica Sinica 2022年第7期38卷 192-200,I0005页

作者： Mengchuan Xu Zeang Zhao Panding Wang Yijin Zhang Xiaogang Guo Hongshuai Lei Daining Fang Beijing Key Laboratory of Lightweight Multi-Functional Composite Materials and Structures Beijing Institute of TechnologyBeijing100081China

A mechanical metamaterial that has a tailorable coefficient of thermal expansion(CTE)is promising for guaranteeing the reliability of electrical and optical instruments under thermal *** growing research on the design and manufacturing of metamaterials with extraordinary CTEs,it remains challenging to achieve a nearly isotropic tailorable CTE while ensuring a sufficient load bearing capacity for applications,such as mechanical supporting *** this research,we propose a type of bi-metallic lattice whose CTE is artificially programmed from positive(75 ppm/K)to negative(−45 ppm/K),and whose equivalent modulus can be as high as 80 *** bi-metallic lattice with a tailorable CTE in two orthogonal directions can be readily assembled without special modifications to construct large-scale planar structures with desired isotropic CTEs.A theoretical model that considers the actual configuration of the bi-metallic joint is developed;the model precisely captures the thermal deformations of lattice structures with varied geometries and material *** by our theoretical design method,planar metallic structures that were manufactured using Al,Ti,and Invar alloy were experimentally characterized;the structures exhibited outstanding performance when compared with typical engineering materials.

关键词： Mechanical metamaterial Metallic lattice coefficient of thermal expansion Load bearing capacity

Microstructure evolution,mechanical properties and tailoring of coefficient of thermal expansion for Cu/Mo/Cu clad sheets fabricated by hot rolling

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Transactions of Nonferrous Metals Society of China 2022年第7期32卷 2290-2308页

作者： Jiang-jiang LIU Ze-jun CHEN Zhan-song ZHOU Tai-qian MO Peng-ju WANG Wei-jun HE Joint International Research Laboratory for Light Alloys Ministry of EducationCollege of Materials Science and EngineeringChongqing UniversityChongqing 400044China

The law of microstructure evolution and mechanical properties of hot roll bonded Cu/Mo/Cu clad sheets were systematically investigated and the theoretical prediction model of the coefficient of thermal expansion(CTE)of Cu/Mo/Cu clad sheets was established *** results show that the deformation of Cu and Mo layers was gradually coherent with an increase in rolling reduction and temperature and excellent interface bonding was achieved under the condition of a large rolling *** development of the microstructure and texture through the thickness of Cu and Mo layers was *** phenomenon can be attributed to the friction between the roller and sheet surface and the uncoordinated deformation between Cu and *** tensile strength of the clad sheets increased with increasing rolling reduction and the elongation was gradually *** CTE of Cu/Mo/Cu clad sheets was related to the volume fraction of *** finite element method can simulate the deformation and stress distribution during the thermal expansion *** simulation result indicates that the terminal face of the clad sheets was sunken inward.

关键词： Cu/Mo/Cu clad sheets roll bonding collaborative deformation mechanical properties coefficient of thermal expansion prediction model

Mechanically Strong and Flame‑Retardant PBO/BN/MXene Nanocomposite Paper with Low thermal expansion coefficient,for Efficient EMI Shielding and Heat Dissipation

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Advanced Fiber Materials 2023年第5期5卷 1657-1670页

作者： Yong Liu Ning Zhao Jian Xu Beijing National Laboratory for Molecular Sciences Laboratory of Polymer Physics and ChemistryInstitute of ChemistryChinese Academy of SciencesBeijing 100190People’s Republic of China University of Chinese Academy of Sciences Beijing 100049People’s Republic of China College of Chemistry and Environmental Engineering Shenzhen UniversityGuangdong 518060People’s Republic of China

As portable and wearable electronic devices are rapidly developing,there is an urgent need for flexible and robust thermally conductive electromagnetic interference shielding materials to address the associated electromagnetic pollution and overheating ***,multifunctional poly(p-phenyl-2,6-phenylene bisoxazole)nanofiber/boron nitride nanosheet/Ti_(3)C_(2)T_(x)MXene nanosheet(PBO/BN/MXene)composite papers are prepared by a gel microparticle-mediated ordered assembly process with the aid of vacuum-assisted ***-like“brick and mortar”structure,segregated structure and sandwich structure are integrated into the composite paper,so that efficient thermally and electrically conductive networks have been *** the BN and MXene contents are 29.2 wt%and 41.7 wt%,the 13μm thick composite paper exhibits an EMI shielding performance of 31.8 dB and a thermal conductivity of 26.1 W/mK,markedly superior to those of the control samples without the ordered ***,because of the unique architecture and inherent advantages of the building blocks,the composite paper exhibits extremely low coefficient of thermal expansion(~1.43 ppm/K),excellent mechanical properties,and outstanding thermal stability and flame retardance,making it highly advantageous for practical applications in electronic *** work offers a promising approach for fabricating high-performance multifunctional composites by constructing efficient filler networks.

关键词： coefficient of thermal expansion EMI shielding Nanocomposite Ordered assembly thermal conductivity

Determination of the thermal expansion coefficient of Concrete at Early Ages by Using Temperature-stress Testing Machine

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Journal of Wuhan University of Technology(Materials Science) 2006年第4期21卷 146-149页

作者：霍凯成 Hubei Key Laboratory of Roadway Bridge & Structure Engineering Wuhan University of TechnologyWuhan 430070China

By using the uptodate temperatuer-stress testing machine, the thermal expansion coefficient of concrete at early ages was studied and indicative conclusions were achieved ： temperature rising due to hydration heat is not directly correlated with cracking, but the temperature and stress evolation process should be taken into consideration in the same time. Proper chemical admixtures and mineral cornpasitions can improve the mechanical properties of concrete such as thermal expansion coefficient, which is very indicative in practice.

关键词： concrete coefficient of thermal expansion temperature-stress test

thermal expansion coefficient for Lead-Graphite and Lead-Iron Metal Matrix Composites

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Thermal Expansion Coefficient for Lead-Graphite and Lead-Iro...

Effects of boron on the microstructure and thermal properties of Cu/diamond composites prepared by pressure infiltration

International Conference on Computer and Information Technology(ICCIT’2012);International Conference on Mechanical,Production and Materials Engineering(ICMPME’2012);International Conference on Electrical and Electronics Engineering(ICEEE’2012);International Conference on Chemical and Environmental Sciences(ICCES’2012);International Conference on Applied and Management Sciences(IAMS’2012);International Conference on Medical and Pharmaceutical Sciences(ICMPS’2012)

作者： Jagannath Kworking S.S.Sharma Chandrashekar Bhat Raghavendra Prabhu the department of Mechanical and Manufacturing Engg

One of the significant features of a composite material is tailorability of its material properties. coefficient of thermal expansion （CTE） of a composite material is known to play a key role in its application area. It has been realized that a state of micro stress often exists between the phase of the matrix and reinforcement. Difference in thermal expansion of the individual phases produces stress which indirectly affects the strength properties and modes of failure. In the present study, coefficient of thermal expansion is measured using metroscope, with a least count of 0.2 microns. Nichrome wire embedded specimens are used for the experiment. The main findings from the experiment is that the coefficient of thermal expansion for both lead-graphite and lead-iron composites increase with the increase in temperature. The rate of coefficient of thermal expansion decreases with increase in weight percentage of graphite or iron.

关键词： Metal matrix composite coefficient of thermal expansion Residual stress Metroscope.

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International Journal of Minerals,Metallurgy and Materials 2011年第4期18卷 472-478页

作者： Ye-ming Fan Hong Guo Jun Xu Ke Chu Xue-xin Zhu Cheng-chang Jia Non-Ferrous Metal Processing Division General Research Institute for Non-ferrous Metals Beijing 100088 China Institute of Powder Metallurgy University of Science and Technology Beijing Beijing 100083 China

Diamond reinforced copper（Cu/diamond） composites were prepared by pressure infiltration for their application in thermal management where both high thermal conductivity and low coefficient of thermal expansion（CTE） are *** were characterized by the microstructure and thermal properties as a function of boron content,which is used for matrix-alloying to increase the interfacial bonding between the diamond and *** obtained composites show high thermal conductivity（660 W/（m·K）） and low CET（7.4×10-6 K-1） due to the formation of the B13C2 layer at the diamond-copper interface,which greatly strengthens the interfacial *** property measurements indicate that in the Cu-B/diamond composites,the thermal conductivity and the CTE show a different variation trend as a function of boron content,which is attributed to the thickness and distribution of the interfacial carbide *** CTE behavior of the present composites can be well described by Kerner＇s model,especially for the composites with 0.5wt% B.

关键词： composite materials pressure infiltration thermal conductivity coefficient of thermal expansion

Evaluation of the microstructure,thermal and mechanical properties of Cu/SiC nanocomposites fabricated by mechanical alloying

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International Journal of Minerals,Metallurgy and Materials 2021年第3期28卷 475-486页

作者： Essam B.Moustafa Mohammed A.Taha Mechanical Engineering Departments Faculty of EngineeringKing Abdulaziz UniversityJeddah 21589Saudi Arabia Solid State Physics Department National Research CentreEl Buhouth St.Dokki12622 GizaEgypt

Nano-sized silicon carbide(SiC:0wt%,1wt%,2wt%,4wt%,and 8wt%)reinforced copper(Cu)matrix nanocomposites were manufactured,pressed,and sintered at 775 and 875℃in an argon atmosphere.X-ray diffraction(XRD)and scanning electron microscopy were performed to characterize the microstructural *** density,thermal expansion,mechanical,and electrical properties were *** analyses showed that with increasing SiC content,the microstrain and dislocation density increased,while the crystal size *** coefficient of thermal expansion(CTE)of the nanocomposites was less than that of the Cu *** improvement in the CTE with increasing sintering temperature may be because of densification of the ***,the mechanical properties of these nanocomposites showed noticeable enhancements with the addition of SiC and sintering temperatures,where the microhardness and apparent strengthening efficiency of nanocomposites containing 8wt%SiC and sintered at 875℃were 958.7 MPa and 1.07 vol%^(−1),*** electrical conductivity of the sample slightly decreased with additional SiC and increased with sintering *** prepared Cu/SiC nanocomposites possessed good electrical conductivity,high thermal stability,and excellent mechanical properties.

关键词： copper matrix nanocomposites silicon carbide coefficient of thermal expansion elastic moduli electrical conductivity mechanical alloying

Mixed Alkali-zinc Effects on Thermo-mechanical Properties in Borosilicate Glasses

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Journal of Wuhan University of Technology(Materials Science) 2024年第5期39卷 1093-1099页

作者： XIAO Guanzhou TAO Yunhang ZHOU Hemin ZHENG Qingshuang QIAO Ang TAO Haizheng State Key Laboratory of Silicate Materials for Architectures Wuhan University of TechnologyWuhan 430070China Wuhan University of Technology Advanced Engineering Technology Research Institute of Zhongshan City Zhongshan 528437China

A series of mixed alkali-zinc borosilicate glasses with various r values(r=molar ratio of[ZnO]/([R^(2)O]+[ZnO]))from 0.00 to 1.00 were fabricated to probe the mixed alkali-zinc effects on thermo-mechanical *** nonlinear evolution of glass transition temperature(T_(g))with the addition of ZnO is ascribed to the competition of two converse factors,i e,the T_(g)depression as one of the colligative properties for a solution,on the one hand,and the enhancement of T_(g)due to the higher field strength of zinc cations compared to that of alkali ***,the nonlinear evolution of elastic moduli and coefficients of thermal expansion with r is attributed to the variance of intermediate-range clusters,which is confirmed by infrared and Raman scattering *** findings are very helpful in tailoring the performance of borosilicate glasses.

关键词： glass transition temperature elastic moduli coefficient of thermal expansion borosilicate glass

Sol-gel Derived TiO_2-Bioactive glass-Hydroxyapatite Bioactive Coating on Titanium Alloy Substrate

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Chinese Journal of Mechanical Engineering 2010年第2期23卷 263-268页

作者： ZHAO Kang LUO Defu TANG Yufei ZHANG Dawei School of Materials Science and Engineering Xi＇ an University of Technology Xi＇ an 710048 China School of Materials Science and Engineering Xihua University Chengdu 610039 China Library of Xi＇ an Polytechnic University Xi＇ an 710049 China

Coating the hydroxyapatite （HA） on the titanium alloy surface can obtain a bioactive implant with high mechanical properties However, the bonding force between the titanium alloy and the HA was low due to their different coefficient of thermal expansion （CET）. Preparing the multi-layer coating with alleviated thermal stress on titanium alloy substrate is few reported. Fabrication of a TiO2-bioactive glass （BG）-HA bioactive coating was proposed to solve this problem. A particular TiO2 surface was prepared on the titanium alloy substrate by micro-arc oxidation treatment. The BG and HA coating were coated onto the TiO2 surface in turn by using a sol-gel method. The microstructure, surface morphology and phase composition of the coatings were analyzed. The bonding force of coatings was investigated by the nick apparatus. In vitro dissolution was performed by soaking the TiO2-BG-HA coated samples into the simulated body fluid for various periods. Micro-structural observations indicated that no delamination and crack occurred at the interface of HA/BG and BG/TiO2. The bonding between the substrate and coating consists of the mechanical interaction and the chemical bonding. The bonding force could reach about 45 N. The TiO2-BG-HA coating displayed the excellent forming ability of bone-like apatite when it was soaked into the simulated body fluid. This work suggests an innovative way to reduce the internal stress among coatings through varying BG composition to adjust its CTE, so as to enhance the bonding force.

关键词： bioactive coating sol-gel coefficient of thermal expansion TiO2-BG-HA simulated body fluid