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Acta Metallurgica Sinica(English Letters) 2022年第12期35卷 2007-2013页

作者： Y.N.Zan X.Lei J.F.Zhang D.Wang Q.Z.Wang B.L.Xiao Z.Y.Ma Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Nuclear Equipment Division Beijing Institute of Nuclear EngineeringChina Nuclear Power Engineering Co.LtdBejing 100840China

B4C reinforced Al composites are widely used as neutron absorbing materials(NAMs)due to excellent neutron absorbing efficiency,however,such NAMs exhibit poor high-temperature *** meet the requirement for structure-function integration,NAMs with enhanced high-temperature mechanical properties are *** this work,a novel(B4 C+Al_(2)O_(3))/Al NAM with netlike distribution of Al_(2)O_(3)was fabricated by powder metallurgy method and subjected to high-temperature tensile creep *** was shown that the creep resistance was enhanced by several orders of magnitude via the addition of only2.1 vol.%netlike-distributed Al_(2)O_(3).(B_(4)C+Al_(2)O_(3))/Al exhibited high apparent stress exponents ranging from 16 to 25 and high apparent activation energy of 364 kJ/*** creep behaviour could be rationalized using the substructure-invariant model and its rupture behaviour could be described by the Dobes-Milicka equation.

关键词： Neutron absorber material Al matrix composite tensile creep B_(4)C/Al

Mechanical Analysis of Concrete Specimen under Restrained Condition

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Journal of Wuhan University of Technology(Materials Science) 2005年第3期20卷 91-94页

作者：马新伟 School of Materials Science and Engineering Harbin Institute of Technology

In order to quantify the development of the tensile stresses and obtain a reliable estimation of the cracking risk, the concrete was subjected to restrained conditions. The fully restrained condition was achieved by keeping the length constant of a concrete specimen. Comparing the free shrinkage with the restrained shrinkage, tensile creep could be discriminated from shrinkage. The testing method was introduced in details, and the mechanical behoviors under tensile lond were analyzed. Results show that conerete exhibits a pronounced viscoelasticity. Under restroined condition, the self-induced tensile stress increases with time. The lower the water to cement ratio, the larger the tensile stress at the same age. The tensile creep of hardening concrete is much larger than that of hardened concrete. The relationships among autogenous shrinkage unter free condition, elastic strain and creep under restrained condition are described, and the mathematical model for the calculation of elastic strain and creep is propased.

关键词： free shrinkage restrained shrinkage tensile creep viscoelasticity

COMPARISON OF FATIGUE AND creep BEHAVIOR BETWEEN 2D AND 3D-C/SiC COMPOSITES

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Acta Metallurgica Sinica(English Letters) 2004年第4期17卷 569-574页

作者： D.Han S.R.Qiao M.Li J.T.Hou X.J.Wu Ultra-high-temperature Thermostructural Composites Laboratory Northwestern Polytechnical UniversityXi'an 710072 China

The differences of tension-tension fatigue and tensile creep characters of 2D-C/SiC and 3D-C/SiC composites have been scrutinized to meet the engineering needs. Experiments of tension-tension fatigue and tensile creep are carried out under vacuum high temperature condition. All of the high temperature fatigue curves are flat; the fatigue curves of the 2D-C/SiC are flatter and even parallel to the horizontal axis. While the tension-tension fatigue limit of the 3D-C/SiC is higher than that of the 2D-C/SiC, the fiber pullout length of the fatigue fracture surface of the 3D-C/SiC is longer than that of the 2D-C/SiC, and fracture morphology of the 3D-C/SiC is rougher, and pullout length of the fiber tows is longer. At the same time the 3D-C/SiC has higher tensile creep resistance. The tensile curve and the tensile creep curve of both materials consist of a series of flat step. These phenomena can be explained by the non-continuity of the damage.

关键词： 2D-C/SiC 3D-C/SiC vacuum high-temperature tensile creep fatigue

Time-dependent Early-age Behaviors of Concrete under Restrained Condition

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Journal of Wuhan University of Technology(Materials Science) 2007年第2期22卷 350-353页

作者：马新伟 R D Hooton H Lam School of Materials Science and Engineering Harbin Institute of Technology Department of Civil Engineering University of Toronto

To investigate the early-age behaviors of concrete under a restrained condition, a set of apparatus was developed. In this way, the tensile creep and other early-age properties can be investigated in depth. By measuring the modulus of elasticity of concrete, synchronous shrinkage of concrete and steel rings and free shrinkage of concrete, the deformations of concrete ring can be quantified respectively. The experimental results show the tensile stress in concrete is time-dependent, and the stress at cracking is much lower than the tensile strength at that age; the tensile creep plays an important role in relaxing the tensile stress and postponing the cracking of concrete.

关键词： shrinkage restrained shrinkage elastic strain tensile creep time-dependent behaviors

Cracking Tendency of Restrained Concrete at Early Ages

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Journal of Wuhan University of Technology(Materials Science) 2008年第2期23卷 263-267页

作者： BA Hengjing SU Anshuang GAO Xiaojian TAO Qi School of Civil Engineering Harbin Institute of Technology Harbin 150006 China

A modified testing system characterized by full automation, steady operation and high accuracy of strain and stress measurements was developed to determine the cracking tendency of high strength concrete （HSC） in restrained condition at early ages. The shrinkage stress and the tensile creep behavior of HSC at early ages were investigated. The influence of W/C ratio and curing conditions on the early-age shrinkage stress and tensile creep was evaluated. It was found that the lower W/C ratio and drying curing condition resulted in higher shrinkage stress, stress induced tensile creep and greater cracking tendency.

关键词： cracking tendency shrinkage stress tensile creep concrete early ages

A Research on the Air Permeability of High Polymer Materials Used to Produce Sports Clothing Fabrics

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Fluid Dynamics & Materials Processing 2023年第5期19卷 1173-1187页

作者： Jike Gao Fawei Li Shangjun Liu National Sports Culture Institute of Gansu Normal College for Nationalities Hezuo747000China Lanzhou University of Finance and Economics Lanzhou747000China

Composite fabrics based on Polytetrafluoroethylene(PTFE)polymer displays several notable *** are waterproof,windproof,permeable to moisture and thermally insulating at the same *** the present study,PTFE fibers are used as raw material to make fiber *** film is formed by crisscrossing interconnected fiber filaments and the related air permeability:tensile creep characteristics and other properties are *** results show that the pore size,thickness,and porosity of the film itself can affect the moisture permeability of the *** water pressure resistance of the selected fabric is 8.5 kPa,and the moisture permeability is 7038 g/(m^(2)·24 h).

关键词： Polytetrafluoroethylene polymer material fiber membrane sports games apparel fabrics air permeability tensile creep

Microstructure Evolution of a Single Crystal Nickel-Base Superalloy During Heat Treatment and creep

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Microstructure Evolution of a Single Crystal Nickel-Base Sup...