应力腐蚀破裂裂尖微观力学场的数值模拟与分析
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摘要
应力腐蚀破裂(SCC)问题是影响核电设备长期安全运行的关键问题之一,也是核电安全研究领域的热点问题之一。由于应力腐蚀破裂是发生在裂纹尖端(断裂过程区)力学作用下的一种电化学行为,受到裂尖区域腐蚀环境、材料和力学的共同影响和作用,是多学科多尺度相交叉的复杂问题,单从某一尺度或单个学科进行研究是无法完全展示出其破坏过程的。针对目前相关研究多是直接基于宏观尺度或纳观尺度,而对微观尺度上的应力腐蚀开裂研究不足。为此,本论文将重点放在微观尺度上应力腐蚀开裂裂尖的力学特性分析上。
本论文通过将数值模拟与理论计算结果对比,验证了利用ABAQUS计算紧凑拉伸试样(1T-CT试样)相关断裂参量的有效性,建立了宏观尺度下裂纹扩展的全局模型和裂尖区域的子模型。全局模型的计算结果为子模型提供边界条件,而子模型的计算为详细了解应力腐蚀破裂裂尖微观力学场提供了保证。本论文在基于应力腐蚀破裂裂尖存在沟形裂纹这一基本观点的基础上,建立了微观尺度下沟形裂纹模型和裂尖分叉裂纹模型,并利用子模型技术建立了微观尺度下沟形裂纹有限元模型和裂尖分叉裂纹有限元模型,分析了微观尺度下应力腐蚀破裂裂尖沟形裂纹长度和分叉裂纹对裂尖氧化膜和基体金属应力应变场的影响。
论文研究结果表明,SCC裂尖氧化膜前端沟形裂纹和裂尖分叉裂纹的存在,会造成氧化膜和基体金属中应力应变的变化,且随着沟形裂纹的长度增加,这种变化越发明显。另一方面,与应力相比,等效塑性应变对裂尖长度变化更加敏感,从一个侧面说明,裂尖等效塑性应变是研究SCC裂尖氧化膜和基体金属比较理想的力学参量。
Stress Corrosion Cracking (SCC) is one of the key factors affecting the long-term safety operation ofnuclear power equipments, which is a hot field in the nuclear safety operation research field. SCC is anelectrochemical behavior which occurred in fracture process zone at the crack tip. Which is interactivelyaffected and acted by the corrosion environment, materials and mechanics at the crack tip and is involvedmultidisciplinary and multi-scale researches. It is almost impossible to reveal the SCC process by usingsingle subject or single scale. Current researches in SCC are based on the macro-scale or directly on thenano-scale, which is skipped micro-scale. Because it is important to understand SCC process in the grainscale, the tasks will focus on the mechanical properties at the SCC tip in micro-scale in this dissertation.
By comparing numerical simulation calculation with theoretical analysis of compact tension specimen(1T-CT specimen) the effectiveness of calculating fracture parameters by using ABAQUS software isverified in the dissertation. A global model involved 1T-CT specimen and a sub-model involved SCC tipregion are constructed, and the calculation of the global model provide the boundary condition forsub-model and the calculation of sub-model provide a detailed investigation on the micro-mechanical fieldat the SCC tip. Based on a basic consideration of a narrow grove-type crack existing at the SCC tip, FEmodels with a grove-type crack and FE model with branch cracks in micro scale are constructed by usingthe sub-model technology in ABAQUS. The effects of the grove-type crack length and branch crack on thestress and strain at the SCC tips are analyzed this dissertation.
The results of investigation indicate that the grove-type crack and branch crack ahead of SCC tip willinduce a great change on the stress and strain in the oxidation film and base metal at the SCC tips, and thechange is more obvious as the grove-type crack length increase. Comparing with the stress, the plasticstrain is more sensitive to the length at the SCC tip. Therefore, the equivalent plastic strain should be anappropriate mechanical parameter to understand the mechanical properties in the oxide film and base metalat the SCC tip.
本论文通过将数值模拟与理论计算结果对比,验证了利用ABAQUS计算紧凑拉伸试样(1T-CT试样)相关断裂参量的有效性,建立了宏观尺度下裂纹扩展的全局模型和裂尖区域的子模型。全局模型的计算结果为子模型提供边界条件,而子模型的计算为详细了解应力腐蚀破裂裂尖微观力学场提供了保证。本论文在基于应力腐蚀破裂裂尖存在沟形裂纹这一基本观点的基础上,建立了微观尺度下沟形裂纹模型和裂尖分叉裂纹模型,并利用子模型技术建立了微观尺度下沟形裂纹有限元模型和裂尖分叉裂纹有限元模型,分析了微观尺度下应力腐蚀破裂裂尖沟形裂纹长度和分叉裂纹对裂尖氧化膜和基体金属应力应变场的影响。
论文研究结果表明,SCC裂尖氧化膜前端沟形裂纹和裂尖分叉裂纹的存在,会造成氧化膜和基体金属中应力应变的变化,且随着沟形裂纹的长度增加,这种变化越发明显。另一方面,与应力相比,等效塑性应变对裂尖长度变化更加敏感,从一个侧面说明,裂尖等效塑性应变是研究SCC裂尖氧化膜和基体金属比较理想的力学参量。
Stress Corrosion Cracking (SCC) is one of the key factors affecting the long-term safety operation ofnuclear power equipments, which is a hot field in the nuclear safety operation research field. SCC is anelectrochemical behavior which occurred in fracture process zone at the crack tip. Which is interactivelyaffected and acted by the corrosion environment, materials and mechanics at the crack tip and is involvedmultidisciplinary and multi-scale researches. It is almost impossible to reveal the SCC process by usingsingle subject or single scale. Current researches in SCC are based on the macro-scale or directly on thenano-scale, which is skipped micro-scale. Because it is important to understand SCC process in the grainscale, the tasks will focus on the mechanical properties at the SCC tip in micro-scale in this dissertation.
By comparing numerical simulation calculation with theoretical analysis of compact tension specimen(1T-CT specimen) the effectiveness of calculating fracture parameters by using ABAQUS software isverified in the dissertation. A global model involved 1T-CT specimen and a sub-model involved SCC tipregion are constructed, and the calculation of the global model provide the boundary condition forsub-model and the calculation of sub-model provide a detailed investigation on the micro-mechanical fieldat the SCC tip. Based on a basic consideration of a narrow grove-type crack existing at the SCC tip, FEmodels with a grove-type crack and FE model with branch cracks in micro scale are constructed by usingthe sub-model technology in ABAQUS. The effects of the grove-type crack length and branch crack on thestress and strain at the SCC tips are analyzed this dissertation.
The results of investigation indicate that the grove-type crack and branch crack ahead of SCC tip willinduce a great change on the stress and strain in the oxidation film and base metal at the SCC tips, and thechange is more obvious as the grove-type crack length increase. Comparing with the stress, the plasticstrain is more sensitive to the length at the SCC tip. Therefore, the equivalent plastic strain should be anappropriate mechanical parameter to understand the mechanical properties in the oxide film and base metalat the SCC tip.
引文
[1]卢建树,王保峰,张九渊.高温水中不锈钢和镍基合金应力腐蚀破裂研究进展,核动力工程[J],2001,22(3):259-263
[2]李学锋,杨中元,秦颢等.新型高铬镍基合金涂层在H2S气氛中抗高温腐蚀性能的研究,稀有金属材料与工程[J],2001,25(6):441
[3]陈长风,姜瑞景,张国安等.镍基合金管材高温高压H2S/CO2环境中局部腐蚀研究,稀有金属材料与工程[J],2010,39(3):427
[4] Y.Sato, H.Xue, Y.Takeda and T.Shoji. Development of a stress corrosion crack testmethodology using tube-shaped specimen, ASTM International-Journal of Testing andEvaluation, 2007, 35(3):254-258
[5]杨武.核电工程材料的应力腐蚀破裂研究,腐蚀科学与防护技术,1995,7(2):87-92
[6] P.Scott and M.L.Calvar. Some possible mechanism of intergranular stress, corrosioncracking of alloy 600 in PWR primary water, in: Proceedings. Sixth InternationalConference of Environmental Degradation of Materials Nuclear Power Systems-WaterReactors, TMS, 1993:657–665
[7] P.L.Andresen, K.Gott and J.L.Nelson. Stress corrosion cracking of sensitized type 304stainless steel in 288°C water: a five laboratory round bobbin, Proceedings of the 9thInternational Symposium on Environmental Degradation of Material in Nuclear PowerSystems-Water Reactors, S. Bruemmer, et al eds, Newport Beach, California,1999:423-433
[8] H.Xue and T.Shoji. Quantitative Prediction of EAC Crack Growth Rate of SensitizedType 304 Stainless Steel in Boiling Water Reactor Environments Based onEPFEM,ASME Transactions-Journal of Pressure Vessel and Technology[J],2007,129(3):460-467
[9]杨卫.宏微观断裂力学,北京:国防工业出版社,1995
[10]李庆芬.断裂力学及其工程应用,哈尔滨:哈尔滨工程大学出版社,2004
[11]赵建生.断裂力学及断裂物理,武汉:华中科技大学出版社,2003
[12]伍义生,陈一坚,曾春华.微观断裂力学,西安:西北工业大学出版社,1987
[13] S.Saxena and N.Ramakrishnan. A comparison of micro, meso and macro scale FEManalysis of ductile fracture in a CT specimen (mode I), Computational Materials Science,2007,39:1-7
[14] S.P.Xiao and T.Belytschko. A bridging domain method for coupling continua withmolecular dynamics. Computer Methods in Applied Mechanics and Engineering,2004,193:1645-1669
[15]钱才富,李慧芳,崔文勇.Ⅰ型裂纹尖端塑性区和无位错区及其对裂纹扩展的影响，材料研究学报，2007,21(6):599-603
[16]褚武扬,谷飚.应力腐蚀机理研究的新进展,腐蚀科学与防护技术, 1995,7(2):97-101
[17]陆永浩,褚武扬,高克玮,乔利杰,T.Shoji.304L不锈钢在高温水中的应力腐蚀裂纹扩展,金属学报, 2004, 40(7):763-767
[18]束国刚,陆念文.压水堆核电厂关键金属部件的老化和寿命评估,中国电力,2006,39(5):53-58
[19]韩恩厚.核电关键材料及焊接部位在微纳米尺度下的环境行为与失效机理,中科院金属研究所,2010,9
[20] J.Hou, T.Shoji, Z.P.Lu, Q.J.Peng, J.Q.Wang, E.H.Han and W.Ke. Residual. strainmeasurement and grain boundary characterization in the heat-affected zone of a weldjoint between Alloy 690TT and Alloy 52, Journal of Nuclear Materials, 2010,397(1-3):109-115
[21] T.Hashimoto and M.Koshishi. Modification of the FRI crack growth model formulationfrom a mathematical viewpoint, Journal of Nuclear Science and Technology, 2009,46:295-302
[22] M.Vankeerberghen, G.Weyns, S.Gavrilov, B.Martens and J.Deconinck. Crackpropagation rate modelling for 316SS exposed to PWR-relevant conditions, Journal ofNuclear Materials, 2009,384(3):274-285
[23] M.M. Hall .An alternative to the Shoji crack tip strain rate equation, Corrosion Science,2008,50:2902–2905
[24] T.Shoji, Z.P.Lu, H.Xue.K.Yoshimoto, M.Itow, J.Kuniya and K.Watanabe, Quantificationof the effects of crack tip plasticity on environmentally-assisted crack growth rates inLWR environments, Environment-Induced Cracking of Materials, 2008:107-122
[25] Q.J.Peng, J.Kwon and T.Shoji. Development of a fundamental crack tip strain rateequation and its application to quantitative prediction of stress corrosion cracking ofstainless steels in high temperature oxygenated water, Journal of Nuclear Materials,2004, 324(1):52-61
[26] H.Xue, Y.Sato and T.Shoji. Quantitative estimation of the growth of environmentallyassisted cracks at flaws in light water reactor components, Transactions of the ASMEJournalof Pressure Vessel and Technology, 2009, 131(1):61-70
[27] A.Thomas, A.Peter and F.Peter. Applying Slip-Oxidation to the SCC of AusteniticMaterials in BWR/PWR Environments, Proceedings of Corrosion'98 conference, NACEInternational, 1998, 262
[28] D.C.Lagoudas, P.Entchev and R.Triharjanto. Modeling of oxidation and its effect oncrack growth in titanium alloys, Computer Methods in Applied Mechanics andEngineering, 2000, 183(1-2): 35-50
[29] T.Shoji, S.Suzuki and R.G.Ballinger. Theoretical Prediction of SCC GrowthBehavior-Threshold and Plateau Growth Rate, Proceedings of Seventh InternationalSymposium on Environmental Degradation of Materials in Nuclear PowerSystems-Water Reactors, Breckenridge, Colorado, 1995:881-889
[30] T.N.Euclydes and R.Claudio. Micromechanics characterization of constraint and ductiletearing effects in small scale yielding fracture, International Journal of Solids andStructures, 2001,38:2171-2187
[31] Y.C.Gao. Exponential stress and strain singularity at tip of mode I growing crack inpower hardening plastic material, Theoretical and Applied Fracture Mechanics, 1996,25(2):103-111
[32] T.Shoji, Z.P.Lu and H.Murakami. Formulating stress corrosion cracking growth rates bycombination of crack tip mechanics and crack tip oxidation kinetics, CorrosionScience,2010,52(3):769-779
[33] X.S.Gao, G.H.Zhang and T.S.Srivasan. A probabilistic model for prediction of cleavagefracture in the ductile-to-brittle transition region and the effect of temperature on modelparameters. Materials Science and Engineering A, 2006,415:264-272
[34]龚敏,余祖孝,陈琳.金属腐蚀理论及腐蚀控制,北京:化学工业出版社，2009
[35]孙戬.多尺度下裂纹断裂过程区细观力学特性分析[D],西安:西安科技大学,2008
[36] P.P.Jason and H.D.Robert. Ductile tearing and discrete void effects on cleavage fractureunder small-scale yielding conditions. International Journal of Solids and Structures,2005,42:3655-3676
[37] R.Claudio, X.S.Gao and H.D.Robert. Transferability of elastic-plastic fracture toughnessusing the Weibull stress approach: significance of parameter calibration, EngineeringFracture Mechanics, 2000,67,101-117
[2]李学锋,杨中元,秦颢等.新型高铬镍基合金涂层在H2S气氛中抗高温腐蚀性能的研究,稀有金属材料与工程[J],2001,25(6):441
[3]陈长风,姜瑞景,张国安等.镍基合金管材高温高压H2S/CO2环境中局部腐蚀研究,稀有金属材料与工程[J],2010,39(3):427
[4] Y.Sato, H.Xue, Y.Takeda and T.Shoji. Development of a stress corrosion crack testmethodology using tube-shaped specimen, ASTM International-Journal of Testing andEvaluation, 2007, 35(3):254-258
[5]杨武.核电工程材料的应力腐蚀破裂研究,腐蚀科学与防护技术,1995,7(2):87-92
[6] P.Scott and M.L.Calvar. Some possible mechanism of intergranular stress, corrosioncracking of alloy 600 in PWR primary water, in: Proceedings. Sixth InternationalConference of Environmental Degradation of Materials Nuclear Power Systems-WaterReactors, TMS, 1993:657–665
[7] P.L.Andresen, K.Gott and J.L.Nelson. Stress corrosion cracking of sensitized type 304stainless steel in 288°C water: a five laboratory round bobbin, Proceedings of the 9thInternational Symposium on Environmental Degradation of Material in Nuclear PowerSystems-Water Reactors, S. Bruemmer, et al eds, Newport Beach, California,1999:423-433
[8] H.Xue and T.Shoji. Quantitative Prediction of EAC Crack Growth Rate of SensitizedType 304 Stainless Steel in Boiling Water Reactor Environments Based onEPFEM,ASME Transactions-Journal of Pressure Vessel and Technology[J],2007,129(3):460-467
[9]杨卫.宏微观断裂力学,北京:国防工业出版社,1995
[10]李庆芬.断裂力学及其工程应用,哈尔滨:哈尔滨工程大学出版社,2004
[11]赵建生.断裂力学及断裂物理,武汉:华中科技大学出版社,2003
[12]伍义生,陈一坚,曾春华.微观断裂力学,西安:西北工业大学出版社,1987
[13] S.Saxena and N.Ramakrishnan. A comparison of micro, meso and macro scale FEManalysis of ductile fracture in a CT specimen (mode I), Computational Materials Science,2007,39:1-7
[14] S.P.Xiao and T.Belytschko. A bridging domain method for coupling continua withmolecular dynamics. Computer Methods in Applied Mechanics and Engineering,2004,193:1645-1669
[15]钱才富,李慧芳,崔文勇.Ⅰ型裂纹尖端塑性区和无位错区及其对裂纹扩展的影响，材料研究学报，2007,21(6):599-603
[16]褚武扬,谷飚.应力腐蚀机理研究的新进展,腐蚀科学与防护技术, 1995,7(2):97-101
[17]陆永浩,褚武扬,高克玮,乔利杰,T.Shoji.304L不锈钢在高温水中的应力腐蚀裂纹扩展,金属学报, 2004, 40(7):763-767
[18]束国刚,陆念文.压水堆核电厂关键金属部件的老化和寿命评估,中国电力,2006,39(5):53-58
[19]韩恩厚.核电关键材料及焊接部位在微纳米尺度下的环境行为与失效机理,中科院金属研究所,2010,9
[20] J.Hou, T.Shoji, Z.P.Lu, Q.J.Peng, J.Q.Wang, E.H.Han and W.Ke. Residual. strainmeasurement and grain boundary characterization in the heat-affected zone of a weldjoint between Alloy 690TT and Alloy 52, Journal of Nuclear Materials, 2010,397(1-3):109-115
[21] T.Hashimoto and M.Koshishi. Modification of the FRI crack growth model formulationfrom a mathematical viewpoint, Journal of Nuclear Science and Technology, 2009,46:295-302
[22] M.Vankeerberghen, G.Weyns, S.Gavrilov, B.Martens and J.Deconinck. Crackpropagation rate modelling for 316SS exposed to PWR-relevant conditions, Journal ofNuclear Materials, 2009,384(3):274-285
[23] M.M. Hall .An alternative to the Shoji crack tip strain rate equation, Corrosion Science,2008,50:2902–2905
[24] T.Shoji, Z.P.Lu, H.Xue.K.Yoshimoto, M.Itow, J.Kuniya and K.Watanabe, Quantificationof the effects of crack tip plasticity on environmentally-assisted crack growth rates inLWR environments, Environment-Induced Cracking of Materials, 2008:107-122
[25] Q.J.Peng, J.Kwon and T.Shoji. Development of a fundamental crack tip strain rateequation and its application to quantitative prediction of stress corrosion cracking ofstainless steels in high temperature oxygenated water, Journal of Nuclear Materials,2004, 324(1):52-61
[26] H.Xue, Y.Sato and T.Shoji. Quantitative estimation of the growth of environmentallyassisted cracks at flaws in light water reactor components, Transactions of the ASMEJournalof Pressure Vessel and Technology, 2009, 131(1):61-70
[27] A.Thomas, A.Peter and F.Peter. Applying Slip-Oxidation to the SCC of AusteniticMaterials in BWR/PWR Environments, Proceedings of Corrosion'98 conference, NACEInternational, 1998, 262
[28] D.C.Lagoudas, P.Entchev and R.Triharjanto. Modeling of oxidation and its effect oncrack growth in titanium alloys, Computer Methods in Applied Mechanics andEngineering, 2000, 183(1-2): 35-50
[29] T.Shoji, S.Suzuki and R.G.Ballinger. Theoretical Prediction of SCC GrowthBehavior-Threshold and Plateau Growth Rate, Proceedings of Seventh InternationalSymposium on Environmental Degradation of Materials in Nuclear PowerSystems-Water Reactors, Breckenridge, Colorado, 1995:881-889
[30] T.N.Euclydes and R.Claudio. Micromechanics characterization of constraint and ductiletearing effects in small scale yielding fracture, International Journal of Solids andStructures, 2001,38:2171-2187
[31] Y.C.Gao. Exponential stress and strain singularity at tip of mode I growing crack inpower hardening plastic material, Theoretical and Applied Fracture Mechanics, 1996,25(2):103-111
[32] T.Shoji, Z.P.Lu and H.Murakami. Formulating stress corrosion cracking growth rates bycombination of crack tip mechanics and crack tip oxidation kinetics, CorrosionScience,2010,52(3):769-779
[33] X.S.Gao, G.H.Zhang and T.S.Srivasan. A probabilistic model for prediction of cleavagefracture in the ductile-to-brittle transition region and the effect of temperature on modelparameters. Materials Science and Engineering A, 2006,415:264-272
[34]龚敏,余祖孝,陈琳.金属腐蚀理论及腐蚀控制,北京:化学工业出版社，2009
[35]孙戬.多尺度下裂纹断裂过程区细观力学特性分析[D],西安:西安科技大学,2008
[36] P.P.Jason and H.D.Robert. Ductile tearing and discrete void effects on cleavage fractureunder small-scale yielding conditions. International Journal of Solids and Structures,2005,42:3655-3676
[37] R.Claudio, X.S.Gao and H.D.Robert. Transferability of elastic-plastic fracture toughnessusing the Weibull stress approach: significance of parameter calibration, EngineeringFracture Mechanics, 2000,67,101-117