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tensile behavior of Strain Hardening Cementitious Composites (SHCC) Containing Reactive Recycled Powder from Various C&D Waste

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Journal of Renewable Materials 2021年第4期9卷 743-765页

作者： Ruixue Wu Tiejun Zhao Peng Zhang Dingyi Yang Miao Liu Zhiming Ma College of Civil Engineering Qingdao University of TechnologyQingdao266033China College of Civil Science and Engineering Yangzhou UniversityYangzhou225127China

This work investigates the feasibility of utilizing reactive recycled powder(RP)from construction and demolition(C&D)waste as supplementary cementitious material(SCM)to achieve a ductile strain hardening cementitious composites(SHCC).The recycled mortar powder(RMP)from mortar waste,recycled concrete powder(RCP)from concrete waste and recycled brick powder(RBP)from clay brick waste were first prepared,and the micro-properties and tensile behavior of SHCC containing various types and replacement ratios of RPs were *** incorporated RP promotes pozzolanic and filler effects,while the hydration products in cementitious materials decrease with RP incorporation;therefore,the incorporated RP decreases the compressive strength of *** to the reduction in the matrix strength,the incorporated RP increases the crack-bridging extent and ductility of SHCC;the irregular micro-structure and high reactivity of RP also help the strain-hardening performance of the prepared *** addition,the strainhardening performance of SHCC containing RMP and RBP is surperior to that of SHCC with RCP and is slightly lower than that of SHCC with fly ash(FA);for instance,the ultimate strain of SHCC containing 54%FA,RMP,RCP and RBP is 3.67%,3.61%,2.52%and 3.53%,*** addition,the strain-hardening behavior of an SHCC doubled mix with FA and RMP or RBP has a similar ultimate strain and a higher ultimate stress than SHCC containing only FA.

关键词： Construction and demolition waste recycled powder strain hardening cementitious composites tensile behavior

tensile behavior of the Second Generation Single Crystal Superalloy DD6

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Journal of Iron and Steel Research International 2015年第8期22卷 738-742页

作者： Zhen-xue SHI Shi-zhong LIU Jian YU Jia-rong LI Science and Technology on Advanced High Temperature Structural Materials Laboratory Beijing Institute of Aeronautical Materials

tensile properties of the second generation single crystal superalloy DD6 were investigated from 20 ℃ to 1 100 ℃. Microstructure evolution and fracture mechanism were examined by scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The results show that the tensile strength decreases slightly with increasing temperature from 20 ℃ to 400 ℃. The tensile strength of the alloy increases with the increase of temperature from 400 ℃ to 800 ℃. Above 800 ℃, the yield strength of the alloy decreases greatly with increasing temperature. The elongation and contraction of area almost present opposite tendency in contrast to changes of the tensile strength. At lower and intermediate temperature （from 20 ℃ to 850 ℃）, the tensile fracture mechanism shows quasi-cleavage mode, while at high temperature （980 ℃ and 1 100 ℃）, it is dimple mode. The γ＇ precipitate morphology still maintains cubic after tensile fracture at lower and intermediate temperature. The γ＇ phase changes into rectangular solid at high temperature. The γ＇ phase is sheared by anti-phase boundary （APB） or stacking faults at lower and intermediate temperature. At high temperature, dislocations overcome γ＇ through by-passing mechanism.

关键词： single crystal superalloy DD6 tensile behavior microstructure evolution

Experimental,analytical and numerical investigation on tensile behavior of twisted fiber yarns

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Chinese Journal of Aeronautics 2021年第5期34卷 278-288页

作者： Xuefeng TENG Duoqi SHI Xin JING Shuangqi LYU Xiaoguang YANG School of Energy and Power Engineering Beihang UniversityBeijing 100083China School of Power and Energy Northwestern Poly technical UniversityXi'an 710072China Aviation Engineering Institute Civil Aviation Flight University of ChinaGuanghan 618307China

Stitched composite materials are emerging as a promising material due to their high interlaminar strength,combined performance and light *** mechanical properties of stitch yarns are very essential for stitched composite *** this study,the tensile behaviors of the twisted fiber yarn in stitched composites were investigated experimentally,analytically and *** kinds of cross-sectional area of twisted yarn are proposed and *** paper presents an intersecting circle model to describe the cross-section of twisted fiber yarns,and a physics-based theoretical model to predict the effective tensile *** numerical models take into account the cross-sectional characteristic and the twist *** investigation shows that:the sum of each fiber area should be used for experimental analysis;and the crosssectional area surrounded by the yarn profile should be used for theoretical predictions and finite element(FE)*** relative errors of the prediction method and the FE simulation are less than 2%and 1%,*** friction between the fibers is derived,and the effect of friction on mechanical properties is *** investigation method will serve as a fundamental component of twisted fiber bundle/yarn analysis.

关键词： Friction Stitched composite tensile behavior Twist Yarn architecture

Effect of Ta on tensile behavior and Deformation Mechanism of a Nickel-Based Single Crystal Superalloy

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Acta Metallurgica Sinica(English Letters) 2024年第11期37卷 1921-1934页

作者： Mingtao Ge Xinguang Wang Yongmei Li Zihao Tan Xipeng Tao Yanhong Yang Liang Wang Chunhua Zhang Song Zhang Yizhou Zhou Xiaofeng Sun Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang110016China School of Materials Science and Engineering Shenyang University of TechnologyShenyang110870China

The effects of Ta on the tensile behavior and deformation mechanisms of a Ni-based single crystal superalloy were investigated in this study from room temperature to elevated *** findings demonstrated that the higher content of Ta could improve the tensile properties of the alloy at different *** to the different deformation mechanisms at various temperatures,the influence of Ta on tensile deformation *** room temperature,the higher content of Ta enhanced the solid solution strengthening,which would enhance the tensile strength of 6.5Ta *** standard heat treatment of 6.5Ta alloy,precipitation of the secondaryγʹphase would hinder the movement of *** the temperature was elevated to 760℃,the higher content of Ta not only promoted the interaction of stacking faults to form Lomer-Cottrell(L-C)locks that impeded dislocation motion,but also reduced the occurrence of dislocation pile-up groups,thus enhancing the yield *** 1120℃,due to the narrowerγchannels and higher APB energy inγʹphase of the alloy with higher Ta addition,the processes of bypassing and shearing of dislocations were hindered,***,the denser and more regular dislocation networks were formed in 6.5Ta alloy;and thus,the tensile strength of 6.5Ta alloy was *** study systematically investigated the effect of Ta on the tensile behavior at three different temperatures,which provided an important theoretical basis for the design of nickel-based single crystal superalloys in the future.

关键词： Ta Single crystal superalloy tensile behavior Stacking fault Deformation mechanism

Quasi-static tensile behavior of large-diameter thin-walled Ti–6Al–4V tubes at elevated temperature

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Chinese Journal of Aeronautics 2016年第2期29卷 542-553页

作者： Tao Zhijun Yang He Li Heng Fan Xiaoguang State Key Laboratory of Solidification Processing School of Materials Science and Engineering Northwestern Polytechnical University Xi'an 710072 China

As promising light-weight and high-performance structure components, large-diameter thin-walled （LDTW） Ti 6Al^4V titanium alloy （TC4） bent tubes are needed most urgently in many industries such as aviation and aerospace. Warm bending may be a feasible way for manufacturing these components. Understanding their temperature and strain rate dependent tensile behavior is the foundation for formability improvement and warm bending design. In this paper, uniaxial ten- sile tests were conducted at elevated temperatures ranging from 298 K to 873 K at tensile velocities of 2, 10, 15 mm/min. The main results show that the tensile behavior of LDTW TC4 tubes is dif- ferent from that of TC4 sheets. The typical elongation of TC4 tubes at room temperature is 10% lower than that of TC4 sheets. The flow stress of TC4 tubes decreases greatly by about 50% with the temperature rising to 873 K. At temperatures of 573-673 K, the hardening exponent is at its highest value, which means the deformation mechanism changes from twining to more dislocation movement by slipping. The fracture elongation of TC4 tubes fluctuates with increasing temperature, which is associated with changes in the deformation mechanism and with the blue brittleness. The fractography of TC4 tubes at various temperatures, especially at 673 K, shows that second phases and impurities significantly influence fracture elongation. By considering the characteristics of the tensile behavior and by properly choosing the die material, the warm bending for TC4 tubes can be achieved at temperatures of 723-823 K.

关键词： Fractography LDTW TC4 tube Strain rate tensile behavior Warm bending

An artificial neural network model on tensile behavior of hybrid steel-PVA fiber reinforced concrete containing fly ash and slag power

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Frontiers of Structural and Civil Engineering 2020年第6期14卷 1299-1315页

作者： Fangvu LIU Wenqi DING Yafei QIAO Linbing WANG Department of Civil and Environmental Engineering Virginia Polytechnic Institute and State UniversityBlacksburgVA 24061USA Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China Key Laboratory of Geotechnical and Underground Engineering(Tongji University) Ministry of EducationShanghai 200092China

The tensile behavior of hybrid fiber reinforced concrete(HFRC)is important to the design of HFRC and HFRC *** study used an artificial neural network(ANN)model to describe the tensile behavior of *** ANN model can describe well the tensile stress-strain curve of HFRC with the consideration of 23 features of *** the model,three methods to process output features(no-processed,mid-processed,and processed)are discussed and the mid-processed method is recommended to achieve a better reproduction of the experimental *** means the strain should be normalized while the stress doesn’t need *** prepare the database of the model,both many direct tensile test results and the relevant literature data are ***,a traditional equation-based model is also established and compared with the ANN *** results show that the ANN model has a better prediction than the equation-based model in terms of the tensile stress-strain curve,tensile strength,and strain corresponding to tensile strength of ***,the sensitivity analysis of the ANN model is also performed to analyze the contribution of each input feature to the tensile strength and strain corresponding to tensile *** mechanical properties of plain concrete make the main contribution to the tensile strength and strain corresponding to tensile strength,while steel fibers tend to make more contributions to these two items than PVA fibers.

关键词： artificial neural network hybrid fiber reinforced concrete tensile behavior sensitivity analysis stress-strain

Grain size and temperature effect on the tensile behavior and deformation mechanisms of non-equiatomic Fe(41)Mn(25)Ni(24)Co8Cr2high entropy alloy

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Journal of Materials Science & Technology 2020年第7期42卷 190-202页

作者： H.T.Jeong W.J.Kim Department of Materials Science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul121-791Republic of Korea

The effect of the grain size on the tensile properties and deformation mechanisms of a nonequiatomic Fe(41)Mn(25)Ni(24)Co8 Cr2 high-entropy alloy was studied in the temperature range between 298 and 1173 K by preparing the samples with three different grain sizes through severe plastic deformation and subsequent annealing:ultrafine(sub)grain size(≤0.5μm),8.1μm and 590.2μ*** the temperature between 298 and773 K,the material with the large grain size of 590.2μm exhibited the largest tensile ductility(57%-82%)due to its high strain hardening associated with mechanical twinning,but it exhibited the lowest strength due to its large grain *** material with the ultrafine(sub)grain size exhibited the lowest tensile ductility(3%-7%)due to a greatly reduced strain hardening ability after severe plastic deformation,but it exhibited the highest strength due to the dislocation strengthening and grain refinement *** tensile testing at temperatures above 973 K,recrystallization occurred in the material with the ultrafine(sub)grains during the sample heating and holding stage,leading to the formation of fine and equiaxed grains with the sizes of 6.8-13.5μ*** deformation behavior of the Fe(41)Mn(25)Ni(24)Co8 Cr2 with different grain sizes in the high temperature range between 973 and 1173 K,where pseudosteady-state flow was attained in the stress-strain curves,could be explained by considering the simultaneous contribution of grain boundary sliding and dislocation-climb creep to total plastic *** activation energies for plastic flow for the materials with different grain sizes were similar as^199 kJ/*** predicting the deformation mechanism,it was important to consider the change in grain size by rapid grain growth or recrystallization during the sample heating and holding stage because grain boundary sliding is a grain-size-dependent deformation *** sample with the ultrafine(sub)grains exhibited the large tensile elongations of 30%-85%due to it

关键词： High entropy alloys Grain size High temperature deformation mechanism tensile behavior Grain boundary sliding

Evaluation of high-temperature tensile behavior for metal foils by a novel resistance heating assisted tensile testing system using samples with optimized structures

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Journal of Materials Science & Technology 2021年第35期94卷 216-229页

作者： Qiu Zheng Tsuyoshi Furushima Department of Mechanical and Biofunctional Systems Institute of Industrial ScienceThe University of Tokyo4-6-1 KomabaMeguro 153-8505TokyoJapan

To evaluate the tensile behavior of metal foils by resistance heating(RH)assisted tensile testing system accurately,this study proposed to embed a digital image correlation(DIC)system with laser speckles for the measurement of full-field strain ***,the sample structures were optimized to achieve uniform temperature and strain *** infrared camera was used to monitor the temperature *** samples instead of dog-bone shaped samples were proposed.A model for calculating the temperature distribution was established to optimize the sample *** parameters that influence the temperature distribution and tensile behavior were *** results,compared to the strain measured by a non-contact extensometer,the maximum deviation of the strain measured by DIC was less than 6%when the nominal strain was larger than *** is confirmed that the proposed tensile testing system is reliable for measuring the temperature and full-field strain *** shape influenced temperature distributions of smaller samples while it almost had no influence on the temperature distributions of larger *** temperature difference was not affected by the material type but by the sample *** proposed rectangular shape was validated to be feasible for RH assisted tensile *** sample length was successfully optimized for a more uniform temperature distribution by the established *** the tensile deformation was not influenced by the sample shape,the temperature distribution resulted in a non-uniform strain distribution before achieving ultimate tensile *** effective sample length between two clamping jigs contributed to a more uniform temperature distribution and material deformation.A more accurate evaluation of high-temperature tensile behavior for metal foils can be achieved by the proposed RH assisted tensile testing system using rectangular samples with an optimized structure.

关键词： High temperature Metal foil Resistance heating Sample structure tensile behavior

Monotonic tensile behavior analysis of three-dimensional needle-punched woven C/SiC composites by acoustic emission

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Journal of University of Science and Technology Beijing 2008年第3期15卷 302-306页

作者： Peng Fang Laifei Cheng Litong Zhang Jingjiang Nie National Key Laboratory of Thcrmostrucmre Composite Materials Northwestern Polytechnical University Xi＇an Shaanxi 710072 China

High toughness and reliable three-dimensional needled C/SiC composites were fabricated by chemical vapor infiltration （CVI）. An approach to analyze the tensile behaviors at room temperature and the damage accumulation of the composites by means of acoustic emission was researched. Also the fracture morphology was examined by S-4700 SEM after tensile tests to prove the damage mechanism. The results indicate that the cumulative energy of acoustic emission （AE） signals can be used to monitor and evaluate the damage evolution in ceramic-matrix composites. The initiation of room-temperature tensile damage in C/SiC composites occurred with the growth of micro-cracks in the matrix at the stress level about 40% of the ultimate fracture stress. The level 70% of the fracture stress could be defined as the critical damage strength.

关键词： C/SiC composites tensile behavior damage damage mechanism acoustic emission