共查询到20条相似文献,搜索用时 10 毫秒
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应力比和频率对GC-4钢CF裂纹扩展特性的影响 总被引:4,自引:0,他引:4
研究了五种应力比和四种频率对GC-4(40CrMnSiMoVA)钢在35%NaCl中性溶溶液中腐蚀疲劳裂纹扩展(CFCG)特性的影响.结果表明,在高应力比时,CFCG的dα/dt-Kmax曲线存在两个平台区PⅠ和PⅡ,且(da/dt)PⅡ<(da/dt)PⅠ.CFCG的da/dN-△K曲线的平台区起始值面△Kp随频率升高呈幂函数关系而降低.从表面电化学反应动力学、裂尖表面形变动力学以及裂尖材料内部氢的扩散动力学三个方面综合考虑,导出了△KP-f的理论函数关系.该函数关系与CFCG试验数据所显示的函数关系十分一致. 相似文献
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应力比和频率对GC-4钢CF裂纹扩展特性的影响 总被引:1,自引:0,他引:1
研究了五种应力比和四种频率对GC-4(40CrMnSiMoVA)钢在35%NaCl中性溶溶液中腐蚀疲劳裂纹扩展(CFCG)特性的影响.结果表明,在高应力比时,CFCG的dα/dt-Kmax曲线存在两个平台区PⅠ和PⅡ,且(da/dt)PⅡ<(da/dt)PⅠ.CFCG的da/dN-△K曲线的平台区起始值面△Kp随频率升高呈幂函数关系而降低.从表面电化学反应动力学、裂尖表面形变动力学以及裂尖材料内部氢的扩散动力学三个方面综合考虑,导出了△KP-f的理论函数关系.该函数关系与CFCG试验数据所显示的函数关系十分一致. 相似文献
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HAN Enhou HAN KYumei ZHENG Yuli KE Wei Corrosion Science Laboratory Institute of Corrosion Protection of Metals Academia Sinica Shenyang China postdoctoral Institute of Corrosion Protection of Metals Academia Sinica Shenyang China 《金属学报(英文版)》1993,6(6):373-378
Based on theoretical analysis about local strain,strain rate and dissolving rate at crack tip,the corrosion fatigue crack growth rate of steels ZG20SiMn and SM50B-Zc in fresh waterand 3.5% NaCl solution were measured experimentally,and the PH and electrode potentialwithin crack were also measured continuously along with crack propagating.It showed thatthe increase of crack growth rate,caused by both decreasing frequency and raising stressratio,was mainly accelerated by hydrogen embrittlement. 相似文献
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EFFECT OF SUBSTRUCTURE AND RESIDUAL STRESS IN STRENGTHENED LAYER ON FATIGUE STRENGTH OF STAINLESS OR LOW CARBON STEEL 总被引:2,自引:0,他引:2
TAN Yuxu REN Liping LI Gang Xi''''an Jiaotong University Xi''''an China TAN Yuxu Associate Professor Institute of Metallic Materials Strength Xi''''an Jiaotong University Xi''''an China 《金属学报(英文版)》1990,3(2):132-137
In the strengthened layer of stainless steel after shot peening,there are a great amount ofdeformation microtwins which may act as structural strengthening factor and prevent thegradual relaxation of surface residual stress during fatigue,so as to keep its rather high levelof bending fatigue strength.However,in the strengthened surface layer of low carbon steel,dislocation cell structure is so unstalbe during fatigue that its surface residual stress relaxationcannot be retarded.Therefore,the bending fatigue strength of the low carbon steel can not beimprored by shot peening. 相似文献
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KANG Zengqiao GAI Xiuying LI Jiabao WANG Zhongguang State Key Laboratory for Fatigue Fracture of Materials Institute of Metal Research Academia Sinica Shenyang China Research Assistant Institute of Metal Research Academia Sinica Shenyang China 《金属学报(英文版)》1992,5(6):477-483
Influence of residual stress and surface morphology induced by shot-peening on fatigue behav-ior of a medium temperature tempered spring steel 60 Mn has been studied.The compressiveresidual stress induced in the near-surface region may improve fatigue limit from 930 to 1010MPa,and the very high tensile residual stress in the interior may reduce it from 1010 to 940MPa,whereas the severe surface damage may cause a drop-off of it from 1010 down to 800MPa.Fatigue cracks initiated in such position where the equivalent Mises stress,includingresidual stress,exceeded the local strength of the material.The compressive residual stress,induced by shot-peening,may intensify the effect of crack closure,so as to decrease the crackgrowth rate. 相似文献
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STUDYONFATIGUEDAMAGEBELOWTHEFATIGUELIMITANDTHECOAXINGEFFECTSWUZhixue;LUWengeandXUHao1)(FushunPetroleuminstitute,Fushun113001,... 相似文献
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Z.X. Wu X. C. Wu Engineering College Yangzhou University Yangzhou China 《金属学报(英文版)》2001,14(4):235-240
1. Introduction The initiation and propagation behavior of short cracks occupies a significant fraction of the fatigue life of unflawed material[13]. For this reason an understanding of the basic characteristics of short cracks in a smooth specimen is very important. There have been some studies concerned with the multiplication of cracks during fatigue in carbon steels[3~1 and a stainless steel1~J. In particular Goto reported that there is a continuous formation of microcracks during the en… 相似文献
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SHORT FATIGUE CRACK BEHAVIOUR IN ISO-STRESS SPECIMENS 总被引:1,自引:0,他引:1
HOGN Youshi LU Yonghua ZHENG Zhemin Institute of Mechanics Academia Sinica Beijing China Institute of Mechanics Academia Sinica Beijing China 《金属学报(英文版)》1990,3(4):276-281
Fatigue tests were made on a vibration machine using specially designed specimens to investi-gate the initiation and propagation features of short fatigue cracks in a weld metal.The spec-imens were triangular in shape so that when loaded as a cantilever beam the surface tensilestress is constant.Test results show that short fatigue cracks mainly originate from slip bandswithin ferrite grains.The development of short fatigue cracks is marked by a gradual increasein crack density with fatigue cycles.Coalescence of short cracks leads to crack propagationand the crack path is predominantly transgranular. 相似文献
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LU Minxu LIU Xiaokun WANG Jianjun FU Xiangjiong ZHENG Xiulin Northwestern Polytechnical University Xi''''an China Lecturer Department No..Northwestern Polytechnical University Xi''''an China 《金属学报(英文版)》1992,5(9):183-189
Comparative investigations were carried out of the effect of heat treatment regimes Jor steelGC-4(40CrMnSiMoVA)on its crack propagating rates,from corrosion fatigue,(da/dN)_(CF),or stress corrosion cracking,(da/dt)_(SCC),in media with various constituentsand pH values.Both(da/dN)_(CF) and(da/dt)_(SCC) accelerate with the increase of yield stressof the steel,yet the former is far less than the later.In comparison with media,the(da/dt)_(SCC) in distilled water is slightly greater than that in 3.5% NaCl solution,and the(da/dN)_(CF) in distilled water is far less than that in 3.5% NaCl solution.With the pH valueincreasing in 3.5% NaCl solution,the(da/dN)_(CF) lowers down and the(da/dt)_(SCC) speedsup.An explanation was also proposed with concept of the cyclic hardening and softening atcrack tip,as well as the crack closure and occluded cell effect. 相似文献
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PEI Hongxun Institute of Corrosion Protection of Metals Academia Sinica Shenyang China Institute of Corrosion Protection of Metals Academia Sinica Shenyang China 《金属学报(英文版)》1989,2(4):284-292
Based on the experimental study of complex biaxial mode Ⅰ fatigue crack growth and thediscussion on Von Mises'theory,a new approach is proposed for correlating crack propaga-tion rate under both in-phase and out-of-phase biaxial stress cycling.The results emphasizethe contribution of plasticity to fatigue crack growth. 相似文献
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在双轴加载条件下对Ⅰ型疲劳裂纹扩展进行了研究。载荷范围从0.08σ_s到0.71σ_3,包括比例加载和非比例加载。基于对Von Mises理论的讨论,提出一个新的力学参数。双轴加载条件下的弹塑性参数P成功地描述了双轴比例加载和非比例加载下的疲劳裂纹扩展。 相似文献