Vynar V. 3. The regularity of corrosion fatigue fracture of surface hardened aluminum alloys

The aim of this work is the study of surface plastic deformation by different methods and electroplating on features of corrosion and corrosive-fatigue fracture of aluminium alloys; the methods are the modern methods of electrochemical, microelectrochemical and corrosive-mechanical tests; The efficiency the solution (0,045% H2SO4 + 0,14% H2O2 + 0,00001% K2Cr2O7) for microelectrochemical investigation of aluminium alloys has been shown. It has been studied how corrosion and fatigue properties of the D16T and AK9M2 aluminium alloys are affected by surface plastic deformation by shot peening and roller burnishing, as well by roughness and electrochemical heterogeneity of surface, formed after the treatment. Mechanism and character of alloys fracture under conditions of fatigue and corrosion fatigue are analysed. Influence of nickel and zinc electroplating (applied for surface preparation before soldering and welding) on corrosion, fatigue and corrosion-fatigue properties of the D16T aluminium alloy are investigated. Nickel and zinc electroplating has been shown to increase corrosion resistance of the alloy, although lower the limit of fatigue when applied to the grinded surface. Previous surface plastic deformation removes the negative impact of electroplating and increase fatigue and corrosion strength. Practical recommendations on preparation of surface before causing of elecrtoplatingm on aluminum alloys are developed.