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constitutive behavior and processing maps of a new wrought magnesium alloy ZE20 (Mg-2Zn-0.2Ce)

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Journal of Magnesium and Alloys 2020年第1期8卷 111-126页

作者： Scott C.Sutton Alan A.Luo Department of Materials Science and Engineering The Ohio State UniversityColumbusOH 43210United States Department of Integrated Systems Engineering The Ohio State UniversityColumbusOH 43210United States Mag Specialties Inc. DenverCO 80210USA

ZE20(Mg-2Zn-0.2Ce)^2 is a new wrought magnesium alloy with improved extrudability and mechanical properties[1].To understand the constitutive behavior and workability of this new alloy,Gleeble thermomechanical testing has been carried out in this *** flow stress behavior of ZE20 was investigated between 250℃–450℃ and 10^–3 s^–1–1.0 s^–1 in isothermal *** descriptions of the flow stress are provided.A new general approach at application of the extended Ludwik equation is demonstrated and was found to be more accurate than the hyperbolic sine Arrhenius model while having a similar number of model *** maps were developed based on the experimental results and are verified with microstructural investigation.A region of safe processing with non-basal texture and high activity of dynamic recrystallization(DRX)was found between 375℃ and 450℃,from 10^–1 s^–1 to 10^–2.5 s^–1.A region of potentially safe processing with annealing that is associated with shear band nucleation of non-basal grains was identified for temperatures as low as 300℃ and rates as high as 10^–1 s^–1.

关键词： Magnesium alloys Thermomechanical processing constitutive behavior Processing map Deformation mechanisms

constitutive behavior, microstructural evolution and processing map of extruded Al-1.1Mn-0.3Mg-0.25RE alloy during hot compression

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Transactions of Nonferrous Metals Society of China 2014年第5期24卷 1337-1345页

作者：张添陶友瑞王学印湖南工程学院机械工程学院湘潭411101 金龙精密铜管集团股份有限公司新乡453000

Hot compression tests of an extruded Al-1.1Mn-0.3Mg-0.25RE alloy were performed on Gleeble-1500 system in the temperature range of 300-500 ℃ and strain rate range of 0.01-10 s-l. The associated microstructural evolutions were studied by observation of optical and transmission electron microscopes. The results show that the peak stress level decreases with increasing deformation temperature and decreasing strain rate, which can be represented by a Zener-Hollomon parameter in the hyperbolic-sine equation with the hot deformation activation energy of 186.48 kJ/mol. The steady flow behavior results from dynamic recovery whereas flow softening is associated with dynamic recrystallization and dynamic transformation of constituent particles. The main constituent particles are enriched rare earth phases. Positive purifying effects on impurity elements of Fe and Si are shown in the ***-0.3Mg-0.25RE alloy, which increases the workability at high temperature. Processing map was calculated and an optimum processing was determined with deformation temperature of 440-450 ℃ and strain rate of 0.01 s-1.

关键词： Al-1.1Mn-0.3Mg-0.25RE alloy flow stress constitutive behavior microstructural characterization processing map

Determination of local constitutive behavior and simulation on tensile test of 2219-T87 aluminum alloy GTAW joints

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Transactions of Nonferrous Metals Society of China 2015年第9期25卷 3072-3079页

作者：李艳军李权吴爱萍麻宁绪王国庆 Hidekazu MURAKAWA 鄢东洋吴会强清华大学机械工程系北京100084 清华大学摩擦学国家重点实验室北京100084 清华大学先进成形制造教育部重点实验室北京100084 Joining and Welding Research Institute Osaka University 中国运载火箭技术研究院北京100076

The local and global mechanical responses of gas tungsten arc welds（GTAW） of a 2219-T87 aluminum alloy were investigated with experiment and numerical *** image correlation（DIC） was used to access the local strain fields in transversely loaded welds and to determine the local stress-strain curves of various regions in the *** results show that the DIC method is efficient to acquire the local stress-strain curves but the curves of harder regions are incomplete because the stress and strain ranges are limited by the weakest *** appropriate extrapolation,the complete local stress-strain curves were acquired and proved to be effective to predict the tensile behavior of the welded *** the tensile process,the fracture initiates from the weld toes owing to their plastic strain concentrations and then propagates along the fusion line,finally propagates into the partially melted zone（PMZ）.

关键词： aluminum alloy tensile behavior digital image correlation constitutive behavior welded joint

Probing the constitutive behavior of microcrystals by analyzing the dynamics of the micromechanical testing system

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Acta Mechanica Sinica 2022年第3期38卷 26-37,I0001页

作者： Peng Wang Zhanli Liu Degang Xie Shaoxing Qu Zhuo Zhuang Danli Zhang Applied Mechanics Laboratory School of Aerospace EngineeringTsinghua UniversityBeijing 100084China Center for Advancing Materials Performance from the Nanoscale(CAMP-Nano) State Key Laboratory for Mechanical Behavior of MaterialsXi'an Jiaotong UniversityXi'an 710049China State Key Laboratory of Fluid Power&Mechatronic System Key Laboratory of Soft Machines and Smart Devices of Zhejiang ProvinceDepartment of Engineering MechanicsZhejiang UniversityHangzhou 310027China

The constitutive behavior of microcrystals remains mysterious since very little,or no information regarding plastic deformation in the measured stress-strain curve is available due to plastic ***,the measured stress-strain curves vary greatly under different control modes,while constitutive behavior should remain unaffected by test *** these reasons,probing the real constitutive behavior of microcrystals has long been a challenge because the nonlinear dynamical behaviors of micromechanical testing systems are ***,we perform and carefully analyze the experiments on singlecrystal aluminum micropillars under displacement control and load *** interpret these experimental results,a lumpedparameter physical model based on the principle of micromechanical testing is developed,which can directly relate nonlinear dynamics of the micromechanical testing system to the constitutive behavior of *** reveals that some stages of the measured stress-strain curve attributed to the control algorithm are not related to constitutive *** solving the nonlinear dynamics of the micromechanical testing system,intense plastic instability(large strain burst)starting from the equilibrium state is attributed to the strain-softening stage of *** studies are also performed to reduce the influence of plastic instability on the measured *** study provides critical insights for developing various constitutive models and designing a reliable micromechanical testing system.

关键词： Plastic instability Micromechanical testing Physical model Nonlinear dynamics constitutive behavior

Global and local constitutive behaviors of friction stir welded AA2024 joints

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Journal of Materials Science & Technology 2017年第9期33卷 987-990页

作者： Pengliang Niu Wenya Li Zhihan Zhang Xiawei Yang State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of Friction Welding TechnologiesNorthwestern Polytechnical University

In this study, the global and local tensile properties of friction stir welded AA2024 joints were measured with the aid of digital image correlation(DIC) method. A novel model was proposed to describe the global and local constitutive behavior of the joints based on DIC data. Different from conventional division of the zones across the joints, a new reasonable division was proposed, i.e. four zones including central low hardness zone(CLHZ), first heat affected zone(HAZ-I) close to TMAZ, second heat affected zone(HAZ-II)close to base metal(BM) and BM in term of the characteristic distribution of hardness. Results reveal that local true stress-true strain curves are different in each zone of interest. Plastic deformation of the joints is concentrated in CLHZ, where the lowest yield stress and the largest strain appear. Therefore, strain localization and necking occur here in a sequence. In addition, the global true stress-true strain curves and yield stresses at various ratios of the width of CLHZ zone to the gauge length are accurately predicted using the proposed constitutive model of the joints.

关键词： Friction stir welding Aluminium alloy Tensile property constitutive behavior

Time- and temperature-dependence of compressive and tensile behaviors of polypropylene fiber-reinforced cemented paste backfill

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Frontiers of Structural and Civil Engineering 2021年第4期15卷 1025-1037页

作者： Iarley Loan Sampaio LIBOS Liang CUI Department of Civil Engineering Lakehead UniversityOntarioP7B 5E1Canada

The understanding of compressive and tensile behaviors of polypropylene fiber-reinforced cemented paste backfill(FR-CPB)play crucial roles in the successful implementation of reinforcement technique in underground mine backfilling ***,very limited studies have been performed to gain insight into the evolution of compressive and tensile behaviors and associated mechanical properties of FR-CPB under various curing temperatures from early to advanced ***,this study aims to investigate the time(7,28,and 90 d)-and temperature(20°C,35°C,and 45°C)-dependence of constitutive behavior and mechanical properties of *** obtained results show that pre-and post-failure behaviors of FR-CPB demonstrate strongly curing temperature-dependence from early to advanced ***,the pseudo-hardening behavior is sensitive to curing temperature,especially at early ***,the mechanical properties including elastic modulus,material stiffness,strengths,brittleness,cohesion,and internal friction angle of FR-CPB show increasing trends with curing temperature as curing time ***,a predictive model is developed to capture the strong correlation between compressive and tensile strength of *** findings of this study will contribute to the successful implementation of FR-CPB technology.

关键词： cemented paste backfill fiber reinforcement constitutive behavior temperature tailings

A temperature/strain-rate-dependent finite deformation constitutive and failure model for solid propellants

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Science China(Physics,Mechanics & Astronomy) 2023年第9期66卷 63-78页

作者： Ming Lei Erhao Chen Zeang Zhao Lihua Wen Jinyou Xiao Xiao Hou School of Astronautics Northwestern Polytechnical UniversityXi’an 710072China Institute of Advanced Structure Technology Beijing Institute of TechnologyBeijing 100081China China Aerospace Science and Technology Corporation Beijing 100048China

The stress-strain response under progressive damage and the ultimate failure of solid propellants are two key issues affecting the integrity of solid rocket *** research primarily focused on the progressive damage in solid propellants during production and ***,they failed to take the temperature/strain-rate-dependent ultimate failures into *** failure strains of solid propellants are experimentally observed to show strong temperature/strain-rate dependence and exhibit an abnormal evolution at low and high temperatures,*** increasing loading strain rate,the failure strains decrease at low temperatures near the glass transition temperature(T_g)but increase at high temperatures far above T_(g).In this study,we introduce the glassy and rubbery failure criteria based on strain energy densities at ultralow and ultrahigh temperatures,respectively,into a viscoelastic constitutive model and build a unified model for the progressive damage and the ultimate failure of solid *** the introduction of these two additional criterion parameters,the developed model can effectively predict the yield-type stress-strain responses,microscopic damage-induced volume dilatations,and temperature/strain-ratedependent ultimate failures of the solid propellants by comparing the model predictions with the experimental *** competition between the glassy failure and the rubbery failure results in the propellants exhibiting a maximum break strain near the glass transition ***,when the strain rate is increased,the propellants exhibit a predominantly glassy response,which shifts the failure envelope toward a higher *** induces an abnormal evolution of failure strains by making the propellants stretchable at high temperatures and brittle at low temperatures.

关键词： viscoelastic material polymeric material constitutive behavior fracture toughness failure envelope

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ON PLASTIC ANISOTROPY OF constitutive MODELFOR RATE-DEPENDENT SINGLE CRYSTAL

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Applied Mathematics and Mechanics(English Edition) 2005年第1期26卷 121-130页

作者：张光张克实冯露 Department of Applied Mechanics Northwestern Polytechnical University (Xi'an) 710072 P.R.China Department of Mechanics School of Civil Engineering and MechanicsShanghai Jiaotong University Shanghai 200240 P.R.China

An algorithm for single crystals was developed and implemented to simulate plastic anisotropy using a rate-dependent slip model. The proposed procedure was a slightly modified form of single crystal constitutive model of Sarma and Zacharia. Modified Euler method, together with Newton-Raphson method was used to integrate this equation which was stable and efficient. The model together with the developed algorithm was used to study three problems. First, plastic anisotropy was examined by simulating the crystal deformation in tension and plane strain compression, respectively. Secondly, the orientation effect of some material parameters in the model and applied strain rate on plastic anisotropy for single crystal also is investigated. Thirdly, the influence of loading direction on the active slip system was discussed.

关键词： constitutive behavior crystal plasticity anisotropy

A unified plasticity methodology for rate-and temperature-sensitive alloys exhibiting a non-linear kinematic hardening behavior

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Acta Mechanica Solida Sinica 2017年第1期30卷 27-37页

作者： Jacques Luk-Cyr Daniel Paquet Jacques Lanteigne Henri Champliaud Aurelian Vadean Department of Mechanical Engineering Ecole Polyechnique de Montreal 2900 Blvd Edouard-Montpetit MontrealQC H3T 1J4 Institut de recherche d'Hydro-Quebec 1800 Blvd Lionel-Boulet Varennes QC J3X 1S1 Department of Mechanical Engineering Ecole de technologie superieure 1100 Rue Notre-Dame O Montreal QCH3C 1K3

In this paper, a novel unified plasticity methodology is proposed to allow the coupling of rate-and temperature-sensitivity of engineering alloys as well as the non-linear kinematic hardening behavior often observed during cyclic loading. The proposed methodology is general in the sense that an arbitrary constitutive model may be chosen for the viscoplastic part, as well as the cyclic part. We adapt our model with a physically-motivated viscoplasticity flow rule and a nonlinear kinematic hardening model. In contrast with other unified plasticity models, the simplified theory involves few material parameters that can be readily calibrated from standard mechanical tests. The capabilities of the proposed theory are demonstrated for a hot rolled annealed 304 L stainless steel supplied by Vimetal Peckover. The model is tested with stress–strain curves obtained from standard tensile and cyclic uniaxial tests at various strain amplitudes and strain-rates, and good accuracy of the response is obtained for strains up to 15%, within a temperature range of 293–673 K. We note that the cyclic plasticity model in our adapted theory can be readily enhanced with ratchetting, mean stress relaxation, strain amplitude history, Masing effects or other complex capabilities.

关键词： Unified plasticity constitutive behavior Viscoplasticity Non-linear kinematic hardening Stainless steels