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A 2-D mesoscopic model for the evaluation of creep damage induced by void growth in polycrystalline metals

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Acta Metallurgica Sinica(English Letters) 2011年第3期24卷 213-219页

作者： Tao YU Kimiaki YOSHIDA Huiji SHI Key Laboratory of Applied Mechanics Department of Engineering Mechanics Tsinghua University Beijing 100084 China v Research Laboratory Ishikawajima-Harima Heary Industries Co. Ltd. Tokyo Japan

At elevated temperature, creep failures of polycrystalline metals after long-term constant loading are often caused by the nucleation, growth and coalescence of creep voids on the grain boundaries. Void h＇action is an important parameter for the evaluation of creep damage level of structural materials operating at high temperature. In this paper, a 2-D numerical simulation method was developed for analyzing the void fraction evolution during the process of creep, based on some hypothesis from experiments. The model was implemented and then was used to predict the evolution of void fraction in the 2.25Cr-1Mo steel of uniaxial creep experiment at 570 ℃, in which the simulation results showed good agreement with the experimental results.

关键词： creep damage Grain boundary Void fraction Voronoi tessellation

Coupling phase field with creep damage to study γ’evolution and creep deformation of single crystal superalloys

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Journal of Materials Science & Technology 2021年第12期71卷 129-137页

作者： Min Yang Jun Zhang Weimin Gui Songsong Hu Zhuoran Li Min Guo Haijun Su Lin Liu State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an710072China Shaanxi Fast Gear Co. Ltd.129 West AvenueXi’an710077China

A phase-field model coupling with elastoplastic de fo rmation and creep damage has been built to study the micro structural evolution and deformation behavior for Ni-Al single crystal alloy during the whole creep *** relevant experiments were conducted to verify the model *** simulation re sults show that under the tensile creep at 1223 K/100 MPa,cubic γ’phases coarsen along the direction parallel to the axis of tensile stress during the first two creep stages;and spindle-shaped and wavy γ’phases are fo rmed during tertiary creep,similar to the experimental *** evolution mechanism of γ’phases is analyzed from the perspective of changes of stress and strain ***"is land-like"γ phase is observed and its formation mechanism is *** the increase of creep stress,the directional coarsening of γ’phase is accelerated,the steady-state creep rate is increased and the creep life is *** comparison between simulated and experimental creep curves shows that this phase-field model can effectively simulate the performance changes during the first two creep stages and predict the influence of creep stresses on creep *** work provides a potential approach to synchronously simulate the creep microstructure and property of superalloys strengthened by γ’precipitates.

关键词： Phase-field model Single crystal superalloy γ’phase creep behavior creep damage

COMPUTER SIMULATION OF creep damage AT CRACK TIP IN SHORT FIBRE COMPOSITES

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Acta Mechanica Sinica 1994年第3期10卷 282-288页

作者：张双寅蔡良武 Institute of Mechanics Chinese Academy of SciencesBeijing 100080China

creep damage at crack tip in short fibre composites has been sim- ulated by using the finite element method(FEM).The well-known Schapery non- linear viscoelastic constitutive relationship was used to characterize time-dependent behaviour of the material.A modified recurrence equation was adopted to accelerate the ***-Rabotnov's damage evolution law was *** growth of the damage zone with time around the crack tip was calculated and the results were shown with the so-called 'digit photo',which was produced by the printer.

关键词： creep damage visco-elasticity finite element method short fibre composite computer simulation

Influence of creep Strength of Weld on Interfacial creep damage of Dissimilar Welded Joint between Martensitic and Bainitic Heat-Resistant Steel

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Journal of Wuhan University of Technology(Materials Science) 2013年第1期28卷 178-183页

作者：张建强 ZHANG Guodong LUO Chuanhong ZHANG Yinglin State Key Laboratory of Advanced Welding and Joint Harbin Institute of Technology School of Power and Mechanical Engineering Wuhan University

The mechanical properties, creep rupture strength, creep damage and failure characteristics of dissimilar metal welded joint （DMWJ） between martensitic （SA213T91） and bainitic heat-resistant steel （12Cr2MoWVTiB（G102）） have been investigated by means of pulsed argon arc welding, high temperature accelerated simulation, mechanical and creep rupture test, and scanning electronic microscope （SEM）. The results show that there is a marked drop of mechanical properties of undermatching joint, and low ductility cracking along weld/G102 interface is induced due to creep damage. creep rupture strength of overmatching joint is the least. The mechanical properties of medium matching joint are superior to those of overmatching and undermatching joint, and creep damage and failure tendency along the interface of weld/G102 are lower than those of overmatching and undermatching joint after accelerated simulation for 500 h, 1 000 h, 1 500 h, and the creep rupture strength of medium matching joint is the same as that of undermatching joint. Therefore, it is reasonable that the medium matching material is used for dissimilar welded joint between martensitic and bainitic steel.

关键词： martensitic heat-resistant steel bainitic heat-resistant steel dissimilar metal welding joint creep damage interracial failure

Research on the creep damage and interfacial failure of dissimilar metal welded joint between 10Cr9Mo1VNbN and 12Cr1MoV steel

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China Welding 2004年第1期13卷 65-70页

作者：张建强赵海燕吴甦鹿安理王煜章应霖 Tsinghua University Wuhan University

The mechanical properties, creep damage, creep rupture strength and features of interfacial failures of welded joints between martensite (SA213T91) and pearlite steel (12Cr1MoV) have been investigated by means of argon tungsten pulsed arc welding, high temperature accelerated simulation, creep rupture, mechanical property tests and scanning electronic microscope (SEM). The research results indicate that the mechanical properties of overmatched and medium matched joint deteriorate obviously, and they are susceptible to creep damage and failure after accelerated simulation operation 500 h, in the condition of preheat 250℃, and post welding heat treatment 750℃×1 h. However, the mechanical properties of undermatched joint are the best, the interfacial failure tendency of undermatched welded joint is less than those of medium and overmatched welded joint. Therefore, it is reasonable that low alloy material TR31 is used as the filler metal of weld between SA213T91and 12Cr1MoV steel.

关键词： dissimilar metal welded joint creep damage interfacial failure creep rupture strength

Nonlinear creep damage model for soft rock under uniaxial compression

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Journal of Coal Science & Engineering(China) 2006年第2期12卷 37-39页

作者：付志亮 Department of Resource and Environmental College Shandong University of Science and TechnologyTai'an 271019China

A nonlinear creep-damage model for soft rock under uniaxial compression waspresented,which takes into account both nonlinear creep and damage growth with *** model is based on the hardening theory,The model is validat... 详细信息

关键词： creep damage nonlinear analysis uniaxial compression mudstone hardening

Study on creep-fatigue damage evaluation for advanced 9%–12% chromium steels under stress controlled cycling

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Acta Metallurgica Sinica(English Letters) 2011年第2期24卷 148-154页

作者： Peng ZHA O Fuzhen XUAN Key Laboratory of Safety Science of Pressurized System Ministry of Education School of Mechanical andPower Engineering East China University of Science and Technology Shanghai 200237 China

creep-fatigue interaction is one of the main damage mechanisms in high temperature plants and their components. Assessment of creep-fatigue properties is of practical importance for design and operation of high temperature components. However, the standard evaluation techniques, i.e. time fraction rule and ductility exhaustion one have limitations in accounting for the effects of control mode on the cyclic deformations. It was found that conventional linear cumulative damage rule failed in accurately evaluating the creep-fatigue life under stress controlled condition. The calculated creep damages by time fraction rule were excessively high, which led to overly conservative prediction of failure lives. In the present study, it was suggested that such over estimation of creep damage was mainly caused by anelastic strain upon stress loading. For precise assessment under conditions of stress control, a modified creep damage model accounting for the effect of anelastic creep was proposed. The assessments of creep fatigue data under stress controlled condition were performed with the new approach developed in this paper for a rotor material and a boiler material used in ultra supercritical power plants. It was shown that a more moderate amount of creep damage was obtained by the new model, which gave better predictions of failure life.

关键词： creep-fatigue creep damage 9%–12%Cr steels Stress control Time fraction rule

A Multiaxial creep damage Hypothesis and Its Application to Predict Life of 2.25%Cr-1%Mo （Bridgeman） Notched Bars

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A Multiaxial Creep Damage Hypothesis and Its Application to ...

MICRO-MACRO damage SIMULATION OF LOW-ALLOY STEEL WELDS SUBJECT TO TYPE IV creep FAILURE

2007国际机械工程与力学会议

作者： NG K Y LAWRENCE Khosrow ZARRABI School of Mechanical and Manufacturing University of New South Wales

A new creep damage model is described. To demonstrate its validity, the mode is applied to 2.25%Cr-1%Mo （Bridgeman） notched bars operating within the creep range. The purpose of the notch in the bar is to generate a triaxial stress/strain field in the notched region. Based on exhaustion of internal energy, the model describes damage as a measure of total deformation due to internal loading in the component and therefore it should be the most appropriate for characterizing gross creep damage on macroscopic level. The paper shows that the model is able to overcome some of the major shortcomings of existing techniques such as those of: Robinson time/strain fraction method, reference stress method, Kachanov-Rabotnov continuum damage mechanics, etc. The results given in the paper show that the new model is capable of predicting creep lives with an accuracy of 1%. Another advantage of the new model is that it is simple and can be readily used in conjunction with any commercial finite element code with creep analysis capabilities.

关键词： creep damage Internal energy Reference Stress Method

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Acta Metallurgica Sinica(English Letters) 2004年第4期17卷 393-399页

作者： T.Igari F.Kawashima T.Tokiyoshi N.Tada Nagasaki R&D Center Mitsubishi Heavy Industries Ltd. Nagasaki 851-0392 JapanNagasaki R&D Center Mitsubishi Heavy Industries Ltd. Nagasaki 851-0392 JapanNagasaki R&D Center Mitsubishi Heavy Industries Ltd. Nagasaki 851-0392 JapanFaculty of Engineering Okayama University Okayama 700-8530 Japan

A simulation method for microscopic creep damage at grain boundaries in the fine-grain heat-affected zone of low-alloy steel welds involving high energy piping was proposed on the basis of the combination of elastic-creep FEM (finite element method) analysis and random fracture resistance modeling of the materials. The procedure to determine the initiation and growth-driving forces of small defects were briefly described. Then, a simulation procedure combining the stress distribution from elastic-creep FEM and the random fracture resistance model was proposed, and Ms procedure was applied to the simulation of the microscopic damage progress in a welded joint model test and in actual power piping. The results in terms of the simulated number density of small defects throughout the wall thickness were in good agreement with the observed results.

关键词： Type IV creep damage welding 2.25Cr-lMo steel high-energy piping numerical simulation small defect