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Effects of orientation on the fatigue crack growth behaviors of the ZK60 magnesium alloy in air and PBS
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作者 Jiaqi Hu Zheng Liu +1 位作者 Zuoliang Ning Hong Gao 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第1期281-294,共14页
Strong anisotropic corrosion and mechanical properties caused by specimen orientations greatly limit the applications of wrought magnesium alloys.To investigate the influences of specimen orientation,the corrosion tes... Strong anisotropic corrosion and mechanical properties caused by specimen orientations greatly limit the applications of wrought magnesium alloys.To investigate the influences of specimen orientation,the corrosion tests and(corrosion)fatigue crack growth tests were conducted.The rolled and transverse surfaces of the materials show distinct corrosion rate differences in the stable corrosion stage,but the truth is the opposite for the initial stage of corrosion.In air,specimen orientations have a significant influence on the plastic deformation mechanisms near the crack tip,which results in different fatigue fracture surfaces and cracking paths.Compared with R-T specimens,N-T specimens show a slower fatigue crack growth(FCG)rate in air,which can be attributed to crack closure effects and deformation twinning near the crack tip.The corrosion environment will not significantly change the main plastic deformation mechanisms for the same type of specimen.However,the FCG rate in phosphate buffer saline(PBS)is one order of magnitude higher than that in air,which is caused by the combined effects of hydrogen-induced cracking and anodic dissolution.Owing to the similar corrosion rates at crack tips,the specimens with different orientations display close FCG rates in PBS. 展开更多
关键词 Magnesium alloy ORIENTATION CORROSION fatigue crack growth
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Vision-based fatigue crack detection using global motion compensation and video feature tracking
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作者 Rushil Mojidra Jian Li +3 位作者 Ali Mohammadkhorasani Fernando Moreu Caroline Bennett William Collins 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2023年第1期19-39,共21页
Fatigue cracks that develop in civil infrastructure such as steel bridges due to repetitive loads pose a major threat to structural integrity.Despite being the most common practice for fatigue crack detection,human vi... Fatigue cracks that develop in civil infrastructure such as steel bridges due to repetitive loads pose a major threat to structural integrity.Despite being the most common practice for fatigue crack detection,human visual inspection is known to be labor intensive,time-consuming,and prone to error.In this study,a computer vision-based fatigue crack detection approach using a short video recorded under live loads by a moving consumer-grade camera is presented.The method detects fatigue crack by tracking surface motion and identifies the differential motion pattern caused by opening and closing of the fatigue crack.However,the global motion introduced by a moving camera in the recorded video is typically far greater than the actual motion associated with fatigue crack opening/closing,leading to false detection results.To overcome the challenge,global motion compensation(GMC)techniques are introduced to compensate for camera-induced movement.In particular,hierarchical model-based motion estimation is adopted for 2D videos with simple geometry and a new method is developed by extending the bundled camera paths approach for 3D videos with complex geometry.The proposed methodology is validated using two laboratory test setups for both in-plane and out-of-plane fatigue cracks.The results confirm the importance of motion compensation for both 2D and 3D videos and demonstrate the effectiveness of the proposed GMC methods as well as the subsequent crack detection algorithm. 展开更多
关键词 global motion compensation fatigue crack detection computer vision parallax effect distortion induced fatigue crack video stabilization camera motion in-plane fatigue crack out-of-plane fatigue crackanalysis
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Fatigue crack propagation of 7050 aluminum alloy FSW joints after surface peening 被引量:1
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作者 金玉花 陈永昇 +2 位作者 马悦铭 王希靖 郭廷彪 《China Welding》 CAS 2023年第1期18-26,共9页
The surface composite modification of the 7050 aluminum alloy friction stir-welded joints was performed by shot peening(SP)/multiple rotation rolling(MRR)and MRR/SP,and the fatigue performance of the nugget zone(NZ)wa... The surface composite modification of the 7050 aluminum alloy friction stir-welded joints was performed by shot peening(SP)/multiple rotation rolling(MRR)and MRR/SP,and the fatigue performance of the nugget zone(NZ)was investigated.The results demonstrated that the fatigue life of SP/MRR samples is longer than that of MRR/SP.On the plane 150μm below the surface.The grains with high angle grain boundary account for 71.5%and 34.3%for MRR/SP and SP/MRR samples,respectively.The crack propagation path of the MRR/SP is transgranular and intergranular,and it is intergranular for the MRR/SP.Multitudinous fatigue striations and some voids appeared at the fracture during the stable crack propagation stage.However,fatigue striations for SP/MRR are with smaller spacing,fewer holes,and smaller size under SP/MRR compared with fatigue fracture of MRR/SP.The differences in fatigue properties and fracture characteristics of the NZ are related to the microstructure after the two combined surface modifications. 展开更多
关键词 7050 aluminum alloy surface compound modification fatigue crack propagation weld nugget zone
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Statistical learning prediction of fatigue crack growth via path slicing and re-weighting
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作者 Yingjie Zhao Yong Liu Zhiping Xu 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2023年第6期415-423,共9页
Predicting potential risks associated with the fatigue of key structural components is crucial in engineering design.However,fatigue often involves entangled complexities of material microstructures and service condit... Predicting potential risks associated with the fatigue of key structural components is crucial in engineering design.However,fatigue often involves entangled complexities of material microstructures and service conditions,making diagnosis and prognosis of fatigue damage challenging.We report a statistical learning framework to predict the growth of fatigue cracks and the life-to-failure of the components under loading conditions with uncertainties.Digital libraries of fatigue crack patterns and the remaining life are constructed by high-fidelity physical simulations.Dimensionality reduction and neural network architectures are then used to learn the history dependence and nonlinearity of fatigue crack growth.Path-slicing and re-weighting techniques are introduced to handle the statistical noises and rare events.The predicted fatigue crack patterns are self-updated and self-corrected by the evolving crack patterns.The end-to-end approach is validated by representative examples with fatigue cracks in plates,which showcase the digital-twin scenario in real-time structural health monitoring and fatigue life prediction for maintenance management decision-making. 展开更多
关键词 fatigue crack growth Structural health monitoring Statistical noises Rare events Digital libraries
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Fatigue crack initiation and early propagation behavior of 2A97 Al-Li alloy 被引量:6
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作者 钟警 钟申 +2 位作者 郑子樵 张海锋 罗先甫 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第2期303-309,共7页
The fatigue crack initiation and early propagation behavior of 2A97 Al-Li alloy was studied. The smooth specimens were fatigued at room temperature under constant maximum stress control when stress ratio (R) is 0.1 ... The fatigue crack initiation and early propagation behavior of 2A97 Al-Li alloy was studied. The smooth specimens were fatigued at room temperature under constant maximum stress control when stress ratio (R) is 0.1 and frequency (f) is 40 Hz. Microstructure observations were examined by optical microscopy, transmission electron microscopy, scanning electron microscopy and electron back scattered diffusion, in order to investigate the relationship between microstructure and fatigue crack initiation and early propagation behavior of 2A97 alloy. The results show that the fatigue cracks are predominantly initiated at inclusions and coarsen secondary phases on the surface of 2A97 alloy. The fatigue crack early propagation behavior of 2A97 alloy is predominantly influenced by the interactions between grain structure and dislocations or persistent slip bands (PSBs). When the misorientation of two neighbouring grains is close to the orientations of the favorable slip plane within these two grains, high-angle grain boundary severely hinders the PSBs passing through, and thus leads to crack bifurcation and deflection. 展开更多
关键词 2A97 Al-Li alloy fatigue crack initiation fatigue crack early propagation
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BLOCK SPECTRUM CHARACTERISTICS AND FATIGUE CRACK RANDOM GROWTH 被引量:1
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作者 杨晓华 姚卫星 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 1995年第2期206-211,共6页
Two parameters,block spectrum intensity Seq and spectrum shape factor a,which describe the characteristics of the loading block spectrum are defined,and the relationship between the parameters and fatigue crack propag... Two parameters,block spectrum intensity Seq and spectrum shape factor a,which describe the characteristics of the loading block spectrum are defined,and the relationship between the parameters and fatigue crack propagation behaviours is investigated.It is shown that the spectrum intensity is an 'average drive force' of fatigue crack propagation,and the variance of fatigue crack size at a given fatigue life is closely related to the spectrum shape factor α. 展开更多
关键词 fatigue crack loading distribution random distribution material scatter block spectrum intensity shape factor
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Effect of annealing treatment on microstructure and fatigue crack growth behavior of Al–Zn–Mg–Sc–Zr alloy 被引量:9
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作者 陈婧 潘清林 +5 位作者 虞学红 李梦佳 邹浩 向浩 黄志其 胡权 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第5期961-975,共15页
Al-Zn-Mg-Sc-Zr alloy samples were annealed to four different states (under-aging, peak-aging, over-aging and double-aging) and then thoroughly investigated by means of electron backscatter diffraction (EBSD), tran... Al-Zn-Mg-Sc-Zr alloy samples were annealed to four different states (under-aging, peak-aging, over-aging and double-aging) and then thoroughly investigated by means of electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), tensile and fatigue crack growth rate tests to explore the influence of annealing treatment on microstmcture and fatigue crack growth behavior. The results indicate that Al3(Sc,Zr) particles can effectively refine grains and enhance tensile properties and fatigue properties. After annealing treatment, the under-aged sample and double-aged sample obtained average grain sizes of 4.9473 and 4.1257 μm, and the maximum value of yield/tensile strength (561 MPa/581 MPa) was obtained in peak-aged state. In the Paris region, fatigue crack growth rate, crack deflection and bifurcation, crack blunting and inter/trans-granular propagation were discussed based on data fitting and Laird model and Griffith theory. And the results show that the under-aged sample possesses the best resistance to fatigue crack propagation and the most tortuous and bifurcated crack path. For all samples, the fatigue crack growth rate in the rupture region was inversely proportional to yield strength. 展开更多
关键词 Al-Zn-Mg-Sc-Zr alloy annealing treatment MICROSTRUCTURES fatigue crack growth rate fatigue crack path
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Influence of chemical liquids on the fatigue crack growth of the AZ31 magnesium alloy 被引量:2
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作者 Zhang-zhong Wang Xian-cong He +3 位作者 Yun-qiang Bai Zhi-xin Ba Yu-ming Dai Heng-zhi Zhou 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2012年第3期225-230,共6页
The fatigue crack growth behavior of an AZ31 magnesium alloy was investigated by comparing the effect of zirconate and phos-phate chemical liquids. The morphology, components, and phase compositions of the chemical de... The fatigue crack growth behavior of an AZ31 magnesium alloy was investigated by comparing the effect of zirconate and phos-phate chemical liquids. The morphology, components, and phase compositions of the chemical depositions at the fatigue crack tip were analyzed by employing scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD), respectively. For samples with and without the chemical liquids, their stress-intensity factor values at the fatigue crack tip were compared by using a stress-strain gauge. The results demonstrated that a zirconate film (ZrxOy-ZnxOy) and a phosphate film (Zn3(PO4)2·4H2O and MgZnP2O7) could be formed on the fatigue crack-surface at the fatigue crack tip. The stress distribution was changed because of the chemical depositions and the causticity of the chemical liquids. This could decrease the stress-intensity factor value and thus effectively cause fatigue crack closure, which reduces the fatigue crack growth rate. Moreover, it was found that the fatigue crack closure effect of zirconates was more positive than that of phosphates. 展开更多
关键词 magnesium alloys fatigue cracks crack closure DEPOSITION fatigue crack propagation
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STOCHASTIC MODELLING OF FATIGUE CRACK GROWTH UNDER CONSTANT AMPLITUDE LOADING
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作者 Jiang Mingxiao Zhu Weiqiu, Zhejiang University, Hangzhou 310027, P. R. China 《Acta Mechanica Solida Sinica》 SCIE EI 1996年第2期169-178,共10页
Two stochastic models of fatigue crack growth under constant amplitude cyclic loading are proposed and studied by using the stochastic averaging method and total probability theorem to account for high frequency compo... Two stochastic models of fatigue crack growth under constant amplitude cyclic loading are proposed and studied by using the stochastic averaging method and total probability theorem to account for high frequency component and low frequency component, respectively, of the irregular nature of fatigue crack growth observed in Virkler's experiment. Particular attention is paid to the prediction performance of the models under a change in the initial crack length. It is shown that the models proposed in the present paper yields better agreement with experimental data than other models available in literature. 展开更多
关键词 stochastic averaging random fatigue crack growth fatigue crack growth cycles
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In-situ quantitative monitoring of fatigue crack using fastest time of flight diffraction method 被引量:2
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作者 杜朝亮 王奕首 +2 位作者 高东岳 刘科海 卿新林 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第11期2679-2684,共6页
Due to the cyclic loading and longtime exposure under extreme environment conditions, fatigue cracks often generate in the aircraft metal structures, i.e. wing skin, fuselage skin, strigners, pylons. These cracks coul... Due to the cyclic loading and longtime exposure under extreme environment conditions, fatigue cracks often generate in the aircraft metal structures, i.e. wing skin, fuselage skin, strigners, pylons. These cracks could cause severe damages to the aircraft structures. Thus the position and size monitoring of fatigue cracks in the metal structures is very important to manufacturers as well as maintenance personnel for significantly improving the safety and reliability of aircraft. Much progress has been made for crack position monitoring in the past few years. However, the crack size monitoring is still very challenging. Fastest time of flight diffraction (FTOFD) method was developed to monitor both the position and size of a crack. FTOFD method uses an integrated sensor network to activate and receive ultrasonic waves in a structure. Diffraction waves will be generated when the ultrasonic waves pass a crack. These diffraction waves are received and analyzed to get the position and size of the crack. The experiment results show that the monitored size of the simulated crack is very close to the real size of the crack, and for frequencies of 350 and 400 kHz, the monitoring errors are both smaller than 5%. 展开更多
关键词 structure health monitoring fatigue crack diffraction waves crack size quantification
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The Role of Particles in Fatigue Crack Propagation of Aluminum Matrix Composites and Casting Aluminum Alloys 被引量:17
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作者 Zhenzhong CHEN Ping HE Liqing CHEN 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2007年第2期213-216,共4页
Fatigue crack propagation (FCP) behaviors were studied to understand the role of SiC particles in 10 wt pct SiCp/A2024 composites and Si particles in casting aluminum alloy A356. The results show that a few particle... Fatigue crack propagation (FCP) behaviors were studied to understand the role of SiC particles in 10 wt pct SiCp/A2024 composites and Si particles in casting aluminum alloy A356. The results show that a few particles appeared on the fracture surfaces in SiCp/Al composites even at high △K region, which indicates that cracks propagated predominantly within the matrix avoiding SiC particles due to the high strength of the particles and the strong particle/matrix interface. In casting aluminum alloy, Si particle debonding was more prominent.Compared with SiCp/Al composite, the casting aluminum alloy exhibited lower FCP rates, but had a slight steeper slope in the Paris region. Crack deflection and branching were found to be more remarkable in the casting aluminum alloy than that in the SiCp/Al composites, which may be contributed to higher FCP resistance in casting aluminum alloy. 展开更多
关键词 Aluminum-matrix composites Casting alloy fatigue crack propagation PARTICLE
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Effects of precipitates on fatigue crack growth rate of AA 7055 aluminum alloy 被引量:8
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作者 陈军洲 甄良 +1 位作者 杨守杰 戴圣龙 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第12期2209-2214,共6页
The effects of precipitates on the fatigue crack growth rate of AA 7055 Al alloy subjected to different ageing treatments were investigated using transmission electron microscope and fatigue crack growth testing.The r... The effects of precipitates on the fatigue crack growth rate of AA 7055 Al alloy subjected to different ageing treatments were investigated using transmission electron microscope and fatigue crack growth testing.The results show that the T77 treated samples exhibit the lowest crack growth rate,while the crack growth rate of over-aged samples is the highest.In terms of the model based on the reversibility of dislocation motion within the plastic zone close to the crack tip,the improved crack growth resistance is attributed to many precipitates that are coherent with Al matrix in the under-aged and T77 treated samples.When the precipitate is coherent with the Al matrix,the larger the precipitate is,the slower the fatigue crack grows.The effects of grain boundary precipitates and precipitate free zone on the fatigue crack growth resistance are less significant than those of precipitates within grains of the alloy. 展开更多
关键词 7055 aluminum alloy ageing fatigue crack growth rate PRECIPITATE
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Effect of Hot Deformation on Formation and Growth of Thermal Fatigue Crackin Chromium Wear Resistant Cast Iron 被引量:11
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作者 CHANG Li-min LIU Jian-hua 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2006年第1期36-39,共4页
The formation and growth of thermal fatigue crack in chromium wear resistant cast iron was investigated, and the effect of hot deformation on the crack was analyzed by means of optical microscope and scanning electron... The formation and growth of thermal fatigue crack in chromium wear resistant cast iron was investigated, and the effect of hot deformation on the crack was analyzed by means of optical microscope and scanning electron microscope and high frequency induction thermal fatigue tester. The results show that eutectic carbide is the main location and passage for initiation and extension of thermal fatigue cracks, hot deformation can improve the eutectic carbiders morphology and distribution, inhibit the generation and propagation of thermal fatigue cracks. In the experiment, the propagation rate of thermal fatigue crack reduces with the quantity of hot deformation increasing, which was analyzed in the point view of the activation energy of crack propagation. 展开更多
关键词 hot deformation chromium wear resistant cast iron thermal fatigue crack
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Fatigue Crack Growth Rate of Ti-6Al-4V Considering the Effects of Fracture Toughness and Crack Closure 被引量:6
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作者 ZHANG Junhong YANG Shuo LIN Jiewei 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2015年第2期409-415,共7页
Fatigue fracture is one of the main failure modes of Ti-6A1-4V alloy,fracture toughness and crack closure have strong effects on the fatigue crack growth(FCG)rate of Ti-6A1-4V alloy.The FCG rate of Ti-6A1-4V is inve... Fatigue fracture is one of the main failure modes of Ti-6A1-4V alloy,fracture toughness and crack closure have strong effects on the fatigue crack growth(FCG)rate of Ti-6A1-4V alloy.The FCG rate of Ti-6A1-4V is investigated by using experimental and analytical methods.The effects of stress ratio,crack closure and fracture toughness on the FCG rate are studied and discussed.A modified prediction model of the FCG rate is proposed,and the relationship between the fracture toughness and the stress intensity factor(SIF)range is redefined by introducing a correcting coefficient.Notched plate fatigue tests(including the fracture toughness test and the FCG rate test)are conducted to investigate the influence of affecting factors on the FCG rate.Comparisons between the predicted results of the proposed model,the Paris model,the Walker model,the Sadananda model,and the experimental data show that the proposed model gives the best agreement with the test data particularly in the near-threshold region and the Paris region,and the corresponding calculated fatigue life is also accurate in the same regions.By considering the effects of fracture toughness and crack closure,the novel FCG rate prediction model not only improves the estimating accuracy,but also extends the adaptability of the FCG rate prediction model in engineering. 展开更多
关键词 TI-6AL-4V fatigue crack growth stress ratio crack closure fracture toughness life prediction
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Effect ofαphase morphology on fatigue crack growth behavior of Ti−5Al−5Mo−5V−1Cr−1Fe alloy 被引量:10
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作者 Kui-wai CHEN Su-ping PAN +1 位作者 Hui-qun LIU Yong JIANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第9期2459-2471,共13页
Taking a Ti−5Al−5Mo−5V−1Cr−1Fe alloy as exemplary case,the fatigue crack growth sensitivity and fracture features with various tailoredαphase morphologies were thoroughly investigated using fatigue crack growth rate(... Taking a Ti−5Al−5Mo−5V−1Cr−1Fe alloy as exemplary case,the fatigue crack growth sensitivity and fracture features with various tailoredαphase morphologies were thoroughly investigated using fatigue crack growth rate(FCGR)test,optical microscopy(OM)and scanning electron microscopy(SEM).The tailored microstructures by heat treatments include the fine and coarse secondaryαphase,as well as the widmanstatten and basket weave features.The sample with coarse secondaryαphase exhibits better comprehensive properties of good crack propagation resistance(with long Paris regime ranging from 15 to 60 MPa·m1/2),high yield strength(1113 MPa)and ultimate strength(1150 MPa),and good elongation(11.6%).The good crack propagation resistance can be attributed to crack deflection,long secondary crack,and tortuous crack path induced by coarse secondaryαphase. 展开更多
关键词 Ti−5Al−5Mo−5V−1Cr−1Fe alloy αphase fatigue crack growth fracture feature
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PROBABILISTIC MODELS FOR LONG FATIGUE CRACK GROWTH RATES OF LZ50 AXLE STEEL 被引量:5
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作者 ZHAO Yong-xiang(赵永翔) +9 位作者 HE Chao-ming(何朝明) YANG Bing(杨冰) HUANG Yu-zhong(黄郁仲) GAO Qing(高庆) WU Ping-bo(邬平波) 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2005年第8期1093-1099,共7页
Experimental study is performed on the probabilistic models for the long fatigue crack growth rates (da/dN) of LZ50 axle steel. An equation for crack growth rate was derived to consider the trend of stress intensity... Experimental study is performed on the probabilistic models for the long fatigue crack growth rates (da/dN) of LZ50 axle steel. An equation for crack growth rate was derived to consider the trend of stress intensity factor range going down to the threshold and the average stress effect. The probabilistic models were presented on the equation. They consist of the probabilistic da/dN-△K relations, the confidence-based da/dN-△K relations, and the probabilistic- and confidence-based da/dN-△K relations. Efforts were made respectively to characterize the effects of probabilistic assessments due to the scattering regularity of test data, the number of sampling, and both of them. These relations can provide wide selections for practice. Analysis on the test data of LZ50 steel indicates that the present models are available and feasible. 展开更多
关键词 LZ50 steel long fatigue crack growth rate average stress THRESHOLD probabilistic model
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EFFECTS OF MICROSTRVCTURE ON FATIGUE CRACK GROWTH BEHMIOR IN Ni-BASE SUPERALLOY GH586 被引量:5
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作者 S.S. Xie X.F. Pan +2 位作者 T.L. Wang Z.X. Wang H.C. Yang and Q. Wang ( School of Materials and Metallurgy, Northeastern Universityl Shenyang 110006, China)( School of Materials and Metallurgy, Northeastern Universityl Shenyang 110006, China)( School of Materia 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1999年第3期267-272,共6页
Threshold stress values, muging from ~8 to 16MPa·m1/2 can be obtained in a Ni-base alloy GH586 by varying the microstructure through heat treatments. The threshold and low crack growth rate behaviors at room tem... Threshold stress values, muging from ~8 to 16MPa·m1/2 can be obtained in a Ni-base alloy GH586 by varying the microstructure through heat treatments. The threshold and low crack growth rate behaviors at room temperature, with varying groin size and γ'-distribution, have been investigated. The results indicate that grain size is an important microstructurol parameter that affects fatigue crack growth threshold and propagation behaviors, as the values of △Kth increase with increasing grain size, but the γ' -distribution also has important effect. Analyses show that the effects of groin size on threshold and low crack-growth rate behavior result from heterogeneous deformation and roughness-induced crack closure due to crystallographic slipping and cracking in coarse microstructure. The higher △Kth and lower fatigue crack growth rate with increasing amounts of fine γ' phases are closely related to less damage accumulation level in deformation zone of crack-tip resulted from heterogeneous deformation due to dislocations' shearing γ' precipitates. 展开更多
关键词 superalloy GH586 fatigue crack growth THRESHOLD grain size γ'-distribution
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Effects of pre-rolling on mechanical properties and fatigue crack growth rate of 2195 Al-Li alloy 被引量:5
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作者 CHEN Meng-xi LI Yi-bo +4 位作者 XIA Lin-yan HUANG Ming-hui WU Zhen-yu YANG Yi QU Zi-jing 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第3期836-847,共12页
While pre-deformation is often conducted before aging treatment to increase the strength and microhardness of 2195 Al-Li alloy, it often increases the fatigue crack growth(FCG) rate and thus reduces the fatigue life o... While pre-deformation is often conducted before aging treatment to increase the strength and microhardness of 2195 Al-Li alloy, it often increases the fatigue crack growth(FCG) rate and thus reduces the fatigue life of the alloy.To determine the effects and causes of pre-deformation and heat treatment on the mechanical properties and FCG rate of2195 Al-Li alloy, and to provide a suitable calculation model for the FCG rate under different pre-deformation conditions, 2195 Al-Li alloy specimens with different degrees of pre-rolling(0, 3%, 6%, and 9%) were investigated. The experimental results indicate that with the increase of pre-rolling, the density of the T1phase and the uniformity of the S′distribution and the microhardness, tensile strength, and yield strength of the alloy increase and at the same time the FCG rate increases, and thus the fatigue life is reduced. It was also found that the normalized stress intensity factor of elastic modulus(E) can be applied to correlate the FCG rate of pre-rolled 2195 Al-Li alloy with constant C and K parameters. 展开更多
关键词 2195 Al-Li alloy pre-rolling OVER-AGING fatigue crack growth mechanical properties
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Fatigue crack growth behaviour of friction stir welded AA7075-T651 aluminium alloy joints 被引量:5
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作者 P.SIVARAJ D.KANAGARAJAN V.BALASUBRAMANIAN 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第8期2459-2467,共9页
The aim of the present work is to evaluate the fatigue crack growth behaviour of 12 mm thick AA 7075-T651 aluminium alloy plates joined by FSW. Fatigue crack growth test was carried out on center cracked tensile (CCT)... The aim of the present work is to evaluate the fatigue crack growth behaviour of 12 mm thick AA 7075-T651 aluminium alloy plates joined by FSW. Fatigue crack growth test was carried out on center cracked tensile (CCT) specimens extracted from the FSW joints and unwelded parent metal. Transverse tensile properties of the unwelded parent metal and welded joints were evaluated. Microstructures of the welded joints were analyzed using optical microscopy and transmission electron microscopy. The scanning electron microscope was used to characterize the fracture surfaces. It was found that the ΔKcr of the welded joint is reduced by 10×10-3 MPa·m1/2 in comparison with the unwelded parent metal. Hence, the fatigue life of the friction stir welded AA 7075-T651aluminium alloy joints is appreciably lower than that of the unwelded parent metal, which is attributed to the dissolution of precipitates in the weld region during friction stir welding. 展开更多
关键词 AA 7075 aluminium alloy friction stir welding fatigue crack growth microstructure
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Simple Predicting Method for Fatigue Crack Growth Rate Based on Tensile Strength of Carbon Steel 被引量:4
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作者 LI Bo HU Ji-fan +3 位作者 QIN Hong-wei MA Nuo AN Kang WANG Xin-lin 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2003年第2期58-62,共5页
Three types of fatigue tests for an annealed carbon steel containing carbon of 0.42%were carried out on smooth specimens and specimens with a small blind hole in order to investigate the fatigue crack growth law.A sim... Three types of fatigue tests for an annealed carbon steel containing carbon of 0.42%were carried out on smooth specimens and specimens with a small blind hole in order to investigate the fatigue crack growth law.A simple predicting method for crack growth rates has been proposed involving strengthσband the relation between cyclic stress and strain.The validity of proposed method has been confirmed by experiments on several carbon steels with different loadings. 展开更多
关键词 fatigue crack growth rate PREDICTION stress gradient carbon steel
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