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163 results on '"Zhu, Li'an"'

2. Preparation and properties of HfO2 coatings by chemical vapor deposition

Author

HE Ruipeng, ZHU Li'an, WANG Zhen, YE Yicong, LI Shun, TANG Yu, and BAI Shuxin

Subjects
cvd, hafnium oxide coating, thermodynamic calculation, emissivity, thermal shock resistance, Materials of engineering and construction. Mechanics of materials, TA401-492
Abstract

HfO2 coatings with a thickness of approximately 8 μm were prepared on the refractory metals Mo surface by using chemical vapor deposition(CVD), and the reaction process of CVD HfO2 was thermodynamically analyzed by HSC Chemistry.The microscopic morphology, self-oriented growth and nanomechanical properties of HfO2 coatings were analyzed, and the bonding force of the coatings with the substrate and thermal shock resistance were tested. The results show that the HfO2 coating is well bonded to the substrate, and no macroscopic flaking occurs on the surface of the coating after 100 cycles of thermal shock from 25 ℃ to 2000 ℃; the adhesion of the coating is about 23 N as determined by the scratch test; the average emissivity of the surface of the coating is 0.48 in the band of 2.5-5 μm, which improves the average emissivity of Mo in the band by nearly 5 times.

Published
2024
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9. Machine learning guided phase and hardness controlled AlCoCrCuFeNi high-entropy alloy design

Author

LI Yahao, YE Yicong, ZHAO Fengyuan, TANG Yu, ZHU Li'an, and BAI Shuxin

Subjects
machine learning, high entropy alloy, phase prediction, hardness prediction, composition design, Materials of engineering and construction. Mechanics of materials, TA401-492
Abstract

Machine learning(ML) assisted high-entropy alloys(HEA) design is dedicated to solving the problem of long period and high cost of designing by traditional trial and error experimental methods. The classic AlCoCrCuFeNi HEA was taken as the research object. The phase structure prediction model and hardness prediction model were established respectively. The support vector machine(SVM) models have the best training performance in both tasks. The best phase classification accuracy is 0.944, and the root mean square error(RMSE) of the hardness regression model is 56.065HV. The two ML models are further connected in series. Based on the upper and lower limits of the data set, the high-throughput prediction and selection of phases and hardness of AlCoCrCuFeNi HEA are carried out simultaneously, thus realizing the efficient composition design of the new alloy. The experimental results show that the five new alloys are in accord with the predicted results, and the RMSE is 12.58HV. It shows that the ML models can predict the phase and hardness of HEA efficiently and accurately.

Published
2024
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15. Research progress in high thermal conductivity of silicon carbide matrix composites reinforced with fibers

Author

CHEN Qiang, LI Shun, ZHU Li'an, BAI Shuxin, and YE Yicong

Subjects
carbon fiber, silicon carbide, high thermal conductivity, composite, Materials of engineering and construction. Mechanics of materials, TA401-492
Abstract

As one kind of advanced high temperature structural and functional materials, it is necessary for fiber reinforced silicon carbide matrix composites (SiC CMCs) in the field of thermal management (TM) to combine the efficient heat transfer and high temperature heat resistance. Common fibers reinforced SiC CMCs, such as carbon fibers reinforced SiC CMCs (Cf/SiC or Cf/C-SiC), silicon carbide based fiber reinforced SiC CMCs (SiCf/SiC), etc., have a low degree of graphitization of the reinforcing fiber and are difficult to form an effective heat transport network. The latest research progress on the preparation and properties of fiber reinforced SiC CMCs with highly thermal conductivity was reviewed in this paper. The heat transport ability of fiber reinforced SiC CMCs can be improved by introducing highly thermal conductive phase, optimizing interfacial structure, making silicon carbide crystal coarse-grained, and designing preform structure. Moreover, the development of the fiber reinforced SiC CMCs with highly thermal conductivities was prospected, that is, comprehensively considering the factors that affect the performance of SiC CMCs, flexibly using the structure-activity relationship between the microstructure and properties of the composites, in order to prepare fiber reinforced SiC CMCs with stable size, excellent properties.

Published
2023
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48. Research of the Shifting Characteristic of Planetary Transmission with using Tooth Brake

Author

Li Yaxi, Ma Biao, Li Heyan, and Zhu Li’an

Subjects
Tooth brake, Joint speed differential, Shifting time, Maximum torque impact, Mechanical engineering and machinery, TJ1-1570
Abstract

The dynamics model of a two-speed planetary transmission is established by using the virtual displacement principle,the dynamic shifting processes comparison and simulation analysis between the planetary transmission using tooth brake and friction brake are carried out. The different joint speed effects on the transmission characteristics are also analyzed through the simulation. The simulation results show that the maximum torque impact of the planetary transmission using tooth brake is lower than using friction brake in the same shifting time. The larger the joint speed difference of the planetary transmission using tooth brake is and the smaller the shifting time is,the greater the maximum torque impact is still lower than the planetary transmission using friction brake.

Published
2017
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