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Creep rupture life predictions for Ni-based single crystal superalloys with automated machine learning

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Rare Metals 2024年第6期43卷 2884-2890页

作者： Chang-Lu Zhou Rui-Hao Yuan Wei-Jie Liao Ting-Huan Yuan Jiang-Kun Fan Bin Tang ping-xiang zhang Jin-Shan Li Turab Lookman State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an 710072China Chongqing Innovation Center Northwestern Polytechnical UniversityChongqing 401120China AiMaterials Research LLC Santa FeNM 87501USA

The state of the art for data-driven creep rupture life predictions incorporates microstructural and deformation characteristics into machine ***,the microstructures and deformation mechanisms for unknown alloys are inaccessible and uncertain before experiments are carried out,and therefore prevents extrapolations of the learned models.

关键词： deformation life creep

Physical properties of WSTi3515S burn-resistant titanium alloy

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Rare Metals 2016年第5期35卷 361-366页

作者： Yun-Jin Lai ping-xiang zhang Xue-Min zhang xiang-Hong Liu Yong Feng Hong-Chao Kou Fan-Jiao Ma Wei-Dong Zeng State Key Laboratory of Solidification Processing Northwestern Polytechnical University Western Superconducting Technologies Co. Ltd. School of Materials Science and Engineering Chang’an University

Development of burn-resistant titanium alloys is the most direct way of mitigating the ignition and propagation of titanium fires in jet engines. WSTi3515S alloy（Ti–35V–15Cr–0.3Si–0.1C） is a new high alloying beta type burn-resistant titanium alloy, belonging to Ti–V–Cr type alloys which have been made significant progress in engineering technology in the past 5 years. The physical properties of WSTi3515S burn-resistant titanium alloy such as the elastic properties and thermal properties were measured and analyzed in different conditions. The results show that both the Young＇s modulus and shear modulus of WSTi3515S alloy decrease slightly with the temperature increasing at the tested temperature range. The Poisson＇s ratio of WSTi3515S alloy is around 0.36. However, the thermal properties such as the specific heat, thermal diffusivity, thermal conductivity and thermal expansion increase with the temperature increasing, which results from the strengthening of lattice heat vibration at elevated temperature. And the room temperature density of WSTi3515S alloy is 5.295 gácm^（-3）.

关键词： Physical properties WSTi3515S alloy Extrusion Burn-resistant

Recrystallization behavior of Ti40 burn-resistant titanium alloy during hot working process

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International Journal of Minerals,Metallurgy and Materials 2016年第5期23卷 581-587页

作者： Yun-jin Lai She-wei Xin ping-xiang zhang Yong-qing Zhao Fan-jiao Ma xiang-hong Liu Yong Feng State Key laboratory of Solidification Processing Northwestern Polytechnical University Xi'an 710072 China Western Superconducting Technologies Co. Ltd. Xi'an 710018 China Northwest Institute for Nonferrous Metal Research Xi'an 710016 China

The recrystallization behavior of deformed Ti40 alloy during a heat-treatment process was studied using electron backscatter dif- fraction and optical microscopy. The results show that the microstructural evolution of Ti40 alloy is controlled by the growth behavior of grain-boundary small grains during the heating process. These small grains at the grain boundaries mostly originate during the forging proc- ess because of the alloy＇s inhomogeneous deformation. During forging, the deformation first occurs in the grain-boundary region. New small recrystallized grains are separated from the parent grains when the orientation between deformation zones and parent grains exceeds a certain threshold. During the heating process, the growth of these small recrystallized grains results in a uniform grain size and a decrease in the av- erage grain size. The special recrystallization behavior of Ti40 alloy is mainly a consequence of the alloy＇s high β-stabilized elemeutal con- tent and high solution strength of the β-grains, which partially explains the poor hot working ability of Ti-V-Cr-type bum-resistant titanium alloys. Notably, this study on Ti40 bum-resistant titanium alloy yields important information related to the optimization of the microstruc- tures and mechanical properties.

关键词： titanium alloys hot working recrystallization microstructural evolution

Influence of pressure disturbance wave on dynamic response characteristics of liquid film seal for multiphase pump

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Petroleum Science 2024年第3期21卷 2048-2065页

作者： Qing-ping Li Jin-Ya zhang Jia-xiang zhang Yong-Xue zhang CNOOC Research Institute Company Limited Beijing100028China State Key Laboratory of Natural Gas Hydrate Beijing100028China College of Mechanical and Transportation Engineering China University of PetroleumBeijing2249China

Slug flow or high GVF(Gas Volume Fraction)conditions can cause pressure disturbance waves and alternating loads at the boundary of mechanical seals for multiphase pumps,endangering the safety of multiphase pump *** mechanical seal model is simplified by using periodic boundary conditions and numerical calculations are carried out based on the Zwart-Gerber-Belamri cavitation ***(User Define Function)programs such as structural dynamics equations,alternating load equations,and pressure disturbance equations are embedded in numerical calculations,and the dynamic response characteristics of mechanical seal are studied using layered dynamic mesh *** results show that when the pressure disturbance occurs at the inlet,as the amplitude and period of the disturbance increase,the film thickness gradually *** the fundamental reason for the hysteresis of the film thickness change is that the pressure in the high-pressure area cannot be restored in a timely *** maximum value of leakage and the minimum value of axial velocity are independent of the disturbance period and determined by the disturbance *** mutual interference between enhanced waves does not have a significant impact on the film thickness,while the front wave in the attenuated wave has a promoting effect on the subsequent film thickness changes,and the fluctuation of the liquid film cavitation rate and axial velocity under the attenuated wave condition deviates from the initial *** with pressure disturbance conditions,alternating load conditions have a more significant impact on film thickness and *** actual operation,it is necessary to avoid alternating load conditions in multiphase pump mechanical seals.

关键词： Multiphase pump Liquid film seal Pressure disturbance wave Dynamic response characteristics

Optimization of sintering parameters for fabrication of Ag-sheathed FeSe superconducting wires

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Rare Metals 2018年第5期37卷 433-438页

作者： Jian-Qing Feng Sheng-Nan zhang Ji-Xing Liu Bo-Tao Shao Cheng-Shan Li Ming Liang ping-xiang zhang Superconducting Materials Research Center Northwest Institute for Non-Ferrous Metal Research School of Materials Science and Engineering Northeastern University School of Materials Science and Engineering Xi'an University of Technology

Ag-sheathed Fe1.05Se superconducting wires were fabricated with ex-situ powder in tube （PIT） process. Fe and Se powders with molar ratio of 1.05 were firstly mixed and sintered under 600 ℃ for 12 h to form precursor powders. Owing to the complex Fe-Se binary phase diagram, both superconducting tetragonal FeSe and nonsuperconducting hexagonal FeSe could be formed simultaneously during sintering. Aiming at the reduction of hexagonal FeSe phase content and higher superconducting phase volume, the influences of key parameters, including sintering time, cooling rate and heating rate, on the phase composition of sintered wires were systematically studied. Optimal sintering parameters are obtained, and the maximum tetragonal FeSe phase content of ~ 97% is achieved. Meanwhile, the effects of packing density of precursor powders on the phase composition of final wires were also discussed. Owing to the shorter length of diffusion path, more tetragonal FeSe was formed with higher packing density. The superconducting transition signal with critical temperature of ~ 7.5 K was obtained, which proved the effectiveness of our optimal sintering process.

关键词： Superconductors FeSe Powder in tube Phase composition Superconducting transition

Oxidative Esterification of Methacrolein to Methyl Methacrylate over Supported Palladium Catalyst

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Chinese Chemical Letters 2006年第6期17卷 739-742页

作者： Wei ZHAO Wei Guo CHENG Zeng Xi LI Lei WANG xiang ping zhang Suo Jiang zhang Institute of Process Engineering Chinese Academy of Sciences Beijing 100080 Graduate University of Chinese Academy of Sciences Beijing 100049

Supported palladium catalysts, which were used in the oxidative esterification of methacrolein to methyl methacrylate, have been prepared with different carriers and Pd precursors. Experimental results revealed that Pd catalysts with r-Al2O3 support and Na2PdC14 precursor showed good performance. Pd catalyst modified with Pb and Mg indicated that Pd-Mg bimetallic catalyst exhibited considerably higher activity and Pd-Pb exhibited both higher activity and selectivity. 92.27% methacrolein conversion and 90.57% methyl methacrylate selectivity were obtained on Pd-Pb-Mg catalyst.

关键词： Oxidative esterification methacrolein methyl methylcralate palladium alumina.

Effect of groove rolling on the microstructure and properties of Cu–Nb microcomposite wires

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International Journal of Minerals,Metallurgy and Materials 2021年第2期28卷 279-284页

作者： Peng-fei Wang Ming Liang Xiao-yan Xu Jian-qing Feng Cheng-shan Li ping-xiang zhang Jin-shan Li School of Materials Northwestern Polytechnical UniversityXi’an 710072China Northwest Institute for Nonferrous Metal Research Xi’an 710016China

Cu–Nb microcomposite wire was successfully prepared by a groove rolling *** effects of groove rolling on the diffraction peaks,microstructure,and properties of the Cu–Nb microcomposite were investigated and the microstructure evolutions and strengthening mechanism were *** tensile strength of the Cu–Nb microcomposite wire with a diameter of 2.02 mm was greater than 1 GPa,and its conductivity reached 68%of the International Annealed Copper Standard,demonstrating the Cu–Nb microcomposite wire with high tensile strength and high conductivity after groove *** results show that an appropriate groove rolling method can improve the performance of the Cu–Nb microcomposite wire.

关键词： groove rolling microstructure strengthening mechanism copper-niobium microcomposites

Effect of high magnetic field on solidification microstructure evolution of a Cu-Fe immiscible alloy

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China Foundry 2022年第4期19卷 335-341页

作者： Yu-jie Yan Chen Wei Yi-xuan He Chao Li ping-xiang zhang Jin-shan Li Jun Wang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an 710072China Xi'an Superconducting Magnet Technology Co. Ltd.Xi'an 710018China Northwest Institute for Nonferrous Metal Research Xi'an 710016China

The liquid phase separation behavior and the evolution of the solidification microstructure of a binary Cu_(50)Fe_(50) alloy were investigated under the conditions of without and with a 10 T magnetic field,with different undercooling during the solidification *** show that the combined effect of Stokes motion and Marangoni convection leads to the formation of the core-shell structure under the condition without the magnetic *** addition,specific gravity segregation is reinforced by increasing the undercooling,resulting in Fe-rich phase drifts towards the sample *** the 10 T magnetic field,the Fe-rich phase is elongated in the parallel direction of the magnetic field under the action of demagnetization energy due to the difference of static magnetic energy and surface *** the vertical direction,through the action of Lorentz force,the convection in the melt is inhibited and Fe-rich phase becomes more ***,the diffusion of the two phases and the coagulation of the Fe-rich phases are also restrained under the magnetic field,therefore,the phase volume fraction of the Fe-rich phase decreases at the same undercooling in the 10 T magnetic *** magnetic field inhibits the segregation behavior in the vertical direction of the magnetic field,and at the same time,improves the gravitational segregation to a certain extent,which has a very important impact on microstructure regulation.

关键词： high magnetic field Cu-Fe immiscible alloy undercooling solidification

Preparation and Magnetic Property of La_(0.7)Sr_(0.3)MnO_3 Nanorod by Combination Sol-Gel with Molten Salt

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Chemical Research in Chinese Universities 2008年第6期24卷 672-674页

作者： QI Shu-yan FENG Jing XU Xiao-dong WANG Jing-ping HOU xiang-yu zhang Mi-lin Key Laboratory of Superlight Materials ＆ Surface Technology of Ministry of Education Harbin Engineering University Harbin 150001 P. R. China

La0.7Sr0.3MnO3（LSMO） nanorods were synthesized by a method combining sol-gel with molten salts at 950 ℃ for 10 h, which employed KCl＋NaCl（mass ratio 4：1） as eutectic molten salts. The morphologies and magnetic properties of the resulting LSMO nanorods were investigated by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, and vibrating sample magnetometer（VSM） measurements. It was found that the obtained perovskite manganite LSMO was a uniform nanorod with a diameter of about 50 nm and a length of longer than 500 rim. The Curie temperature（To） of the LSMO nanorod used here was 262 K, much lower than that of bulky single crystal LSMO（360 K）. The low Curie temperature might be a result of the great disorder near the grain boundary, which could be observed clearly from the TEM picture.

关键词： Molten salt synthesis Sol-gel processes Perovskite Nanostructured materials