Analysing Micromechanisms of Initiation and Propagation of Short Fatigue Cracks from Rivet Holes in the Aluminums Sheets

Researched initiation and propagation of short surfaces fatigue cracks out of open in double-sided botch laminated sheet of aviation aluminum alloy 2024-T3 at stable amplitude one-sided bend (R=0.1). Research of the initial stage of development of cracks is realized by use of a SEM microscope, and it allowed to set the place of origin of crack and mikromechanisms of fracture of aluminum sheets, and also type of front of crack. Established a large enough scatter of velocity of propagation in the area of development of short cracks, which for a sheet from this alloy, with a thickness of 3 mm, reaches 0.5 mm. On the basis of fractografy researches modified model of analytical description of propagation of short fatigue crack is proposed.