The stress corrosion crack(SCC) susceptibility of ultra-high strength steel AerMet 100 was investigated by slow strain rate technique(SSRT),tensile with polarization and surface analysis technique.The curves of t fC l/tfW-strain rate are divided into three regions:stress-dominated region,SCC-dominated region,and corrosion-dominated region,so as the curves of tfCl/tfW-strain rate and tm/tf-strain rate.The results of tensile tests with polarization show that the main SCC mechanism of AerMet 100 is anodic dissolution,which controls the corrosion process.The three regions have been discussed according to the relationship between the rate of slip-step formation and the rate of dissolution.Fracture appearances in different environments were analyzed by scanning electron microscopy(SEM).SCC fracture appears as a mixture of intergranular and dimples,while it is totally dimples in the inert environment.The εf becomes the parameter to predict tf because the relationship between tfCl/tfW and tfC l/tfW is a straight line for AerMet 100.
Anodic oxide films of titanium alloy Ti-10V-2Fe-3Al were sealed in calcium acetate solution. The morphology and composition of the sealed films were investigated using scanning electron microscopy (SEM), atomic force microscope (AFM) and energy dispersive spectroscopy (EDS). The results show that the sealing process makes the anodic oxide films more uniform. Elemental calcium is presented through the whole depth of the anodic oxide films. The roughness of the anodic oxide films is reduced after the sealing process. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization were used to study the corrosion behavior of the anodic oxide films. It is revealed that the sealing process improves the corrosion resistance of the anodic oxide film of titanium alloy Ti-10V-2Fe-3Al.
Anodizing is always used as an effective surface modification method to improve the corrosion resistance and wear resistance of titanium alloy.The sodium tartrate anodizing is a new kind of environmental anodizing method.In this work, the effects of sodium tartrate anodizing on mechanical property were studied.The oxide film was performed on the TA15 titanium alloy using sodium tartrate as the film former.The effects of this anodizing and the traditional acid anodizing on the fatigue life of TA15 alloy were compared.The results show that the sodium tartrate anodizing just caused a slight increase of hydrogen content in the alloy, and had a slight effect on the fatigue life.While, the traditional acid anodizing caused a significant increase of hydrogen content in the substrate and reduced the fatigue life of the alloy significantly.
