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Corrosion fatigue behavior of a steel with sprayed coatings 总被引:1,自引:0,他引:1
K. Tokaji T. Ogawa J. U. Hwang Y. Kobayashi Y. Harada 《Journal of Thermal Spray Technology》1996,5(3):269-276
This paper describes the corrosion fatigue behavior and fracture mechanisms of a steel with different sprayed coatings. Rotating
bending fatigue tests were conducted in 3% NaCl solution using specimens of a medium carbon steel with sprayed coatings of
a ceramic (Cr2O3), a cermet (WC-12%Co) and two metals (Ni-11 % P and Al-2% Zn). The corrosion fatigue process was basically the same for ceramic, cermet, and Ni-11 % P sprayed specimens. That is,
the corrosive media could be supplied from the specimen surface to the substrate through cracks initiated during fatigue cycling
and/or pores in the coatings, and thus corrosion pits were generated followed by subsequent crack initiation and growth in
the substrate. The corrosion fatigue strength of ceramic sprayed specimens was slightly improved compared to that of the substrate
steel because the under-coating (Ni-5%A1) could impede the penetration of the corrosive media although the ceramic coating
had a poor resistance to cracking under cyclic loading. Cermet sprayed specimens also exhibited improved corrosion fatigue
strength because of the high resistance to cracking and the low volume fraction of pores of the coating. In Ni-11 % Psprayed
specimens, cracks were initiated in the coating even at low stress levels; thus the corrosion fatigue strength was the same
as that of the substrate. Anodic dissolution took place in Al-2 % Zn coating because the coating was electrochemically poor,
and thus the substrate was cathodically protected. Therefore, the corrosion fatigue strength of Al-2 % Zn sprayed specimens
was enhanced to as high as the fatigue strength of the substrate in room air. Based on the experimental results, a dual-layer
coating consisting of WC-12%Co and Al-2%Zn was fatigue tested. The coating was effective at low stress levels and exhibited
long life under conditions where corrosion fatigue strength was critical. 相似文献
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利用SEM对实际使用时断裂的髋关节的断口和表面进行了分析,认为此关节的断裂为以弯曲应力为主的腐蚀疲劳断裂。疲劳裂纹首先在表面的腐蚀点孕育产生,应力和腐蚀的共同作用使得裂纹得以扩展断裂。 相似文献
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Fatigue behavior has been studied on gas-nitrided smooth specimens of commercial pure titanium, an alpha/beta Ti-6Al-4V alloy,
and a beta Ti-15Mo-5Zr-3Al alloy under rotating bending, and the obtained results were compared with the fatigue behavior
of annealed or untreated specimens. It was found that the role of the nitrided layer on fatigue behavior depended on the strength
of the materials. Fatigue strength was increased by nitriding in pure titanium, while it was decreased in the Ti-6Al-4V and
Ti-15Mo-5Zr-3Al alloys. Based on detailed observations of fatigue crack initiation, growth, and fracture surfaces, the improvement
and the reduction in fatigue strength by nitriding in pure titanium and both alloys were primarily attributed to enhanced
crack initiation resistance and to premature crack initiation of the nitrided layer, respectively. 相似文献
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Yu. S. Zhukova Yu. A. Pustov A. S. Konopatsky M. R. Filonov S. D. Prokoshkin 《Journal of Materials Engineering and Performance》2014,23(7):2677-2681
The aim of the present work was to study corrosion and electrochemical behavior of Ti-22Nb-6Ta and Ti-22Nb-6Zr (at.%) superelastic alloys under conditions which imitate the performance mode of target devices (bone implants), i.e., under cyclic load in simulated physiological solutions. Open circuit potential (OCP) measurements were carried out on wire specimens in Hank’s solution and artificial saliva at 37 °C with various strain values up to 1.5%. It is shown that at clinically relevant strain values (about 0.2%) the alloys exhibit OCP growth indicating their high stability and resistance to corrosion fatigue under these cycling conditions. At much higher strains (about 1%), fatigue crack initiation and propagation take place, however, the corresponding OCP variation indicates that the fracture process is significantly restrained by reversible martensitic transformation during cycling. 相似文献
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S135钻杆钢预腐蚀后的弯曲疲劳性能 总被引:1,自引:1,他引:0
目的:考察有机盐钻井液对S135钻杆材料腐蚀及疲劳性能的影响。方法首先利用高温高压釜模拟有机盐钻井液井筒的工况环境,对疲劳试样进行预腐蚀,通过点蚀仪测定试样表面的腐蚀状况;然后利用旋转弯曲疲劳试验机在不同弯曲应力条件下对预腐蚀试样和未腐蚀试样的疲劳性能进行测试,算得不同存活率下的疲劳强度,并绘制不同存活率下的S-N曲线。用体视显微镜和扫描电镜观察预腐蚀试样和未腐蚀试样的疲劳断口形貌,进而得出S135钻杆材料表面腐蚀对其疲劳寿命的影响程度和影响机制。结果经过腐蚀的试样表面有较多腐蚀坑,腐蚀坑深度在0.4~0.7 mm之间。未腐蚀试样的疲劳强度为553 MPa,其疲劳断口只观察到单个疲劳裂纹源;腐蚀试样的疲劳强度为409 MPa,其疲劳断口观察到多个疲劳裂纹源。 S135钻杆材料腐蚀疲劳开裂敏感性指数为26%。结论经过高温高压有机盐钻井液环境腐蚀后,试样表面点蚀严重,腐蚀坑底部存在应力集中并导致裂纹源的形成,多个裂纹源的同时生长加快了裂纹的扩展,最终降低S135钻杆钢的疲劳强度。 相似文献
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FENG Tao CHEN Liangshi KE Wei Corrosion Science Laboratory Institute of Corrosion Protection of Metals Academia Sinica Shenyang China 《金属学报(英文版)》1991,4(9):168-173
The environment-sensitive fracture behaviour of 0Cr18Ni9Ti austenitic stainless steel inboiling 42% MgCl_2 under the specific load of low frequency and high mean stress was inves-tigated from the relations and differences of crack growth rates and fractographs betweenstress corrosion fatigue and stress corrosion cracking.The interaction between stress corro-sion cracking and corrosion fatigue was also studied from fracture characteristics with empha-sis on the effects of applied potential on the interaction. 相似文献
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Jürgen Vollmar Rainer Eckrich Stefan Lotz Kurt Marchetti Hans-Joachim Mayer Manfred Rammo Ronald Ritter Guntram Wagner Wolfgang Guth 《工业材料与腐蚀》1992,43(10):475-482
Corrosion fatigue behaviour of steel Ck 45 in aqueous solutions containing chloride ions The fatigue behaviour of carbon steel Ck 45 (comparable to AISI 1045x) is investigated for cyclic tension and rotating bending load with a frequency of 25 Hz. The fatigue limits under cyclic tension load in air are 410 N/mm2 for smooth specimens and 290 N/mm2 for notched specimens. For rotating bending load a value of 200 N/mm2 is found for smooth specimen. The fatigue limits for N = 107 in two different environments (0.3% and 3% NaCl-solution) reach only 37–57% of the according values in air. Cathodic protection of smooth specimens causes an improvement to 95% of the air fatigue limit. The evaluation of the free corrosion potential for all corrosion fatigue tests and the appearence of fracture show typical attributes of corrosion fatigue in the active state. 相似文献
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Improvement of the corrosion fatigue behavior of steels by paint-coating Paint-coatings have been used extensively to prevent corrosion of steel. In order to investigate the influence of an anticorrosive paint on the corrosion fatigue strength of steel, specimens of SAE 4135 in a quenched and tempered state, and in salt bath nitrocarburized state, on the one hand, and specimens of the steel SAE 5115 in a salt bath carburized state, on the other hand, were subjected to comparative rotating bending fatigue tests in inert media and in aqueous 5 pct NaCl. The results demonstrate that the 5 pct NaCl environment is reducing fatigue life drastically, but the painting treatment, however, was found to improve significantly the corrosion fatigue life. Regarding the beneficial effect of the painting treatment on the corrosion fatigue behavior, a superiority of the nitrocarburized variant in contrast to the other variants was ascertained. 相似文献