Kalakhan O. Regularities and mechanism of corrosion and corrosion-mechanical fracture of titanium alloys in the environments of different protogenity

Object: corrosion and corrosion-mechanical fracture of titanium alloys , including those with gas-thermal coatings. Aim: improvement of corrosion -fatigue durability of alloys, including by the restoring gas-thermal coatings in environments with different protogenity. Methods: voltammetry, optical, electron-microscope metallography, X-ray diffraction and point micro X-ray spectral analyses, fretting fatigue, fracture mechanics approaches. Results: new approaches to the solution of the problem of improving corrosion-fatigue durability of alloys in technological environments and at the presence of the protective coatings on them have been proposed; the inversion of the effect of aqueous ammonia solutions on the resistance of fatigue crack initiation from a stress notch and crack growth kinetics has been established. Novelty: a different- stage anode oxidation of alloys in aproton and protogene environments has been revealed; quantitative characteristics of the effect of cyclic deformation on alloy repassivation have been obtained; a different mechanism of the corrosion-fatigue cracks propagation , depending on loading amplitude has been established; limiting stages of coating corrosion have been determined and the mechanism of their local corrosion development has been clarified. Introduction: prevention of fretting-fatigue fracture of turbine titanium blades at NPP. Application: power generating industry, chemical industry, engineering centers.