Abstract
Initiation and growth of short cracks was studied in 1441 aluminium-lithium alloy produced in Russia in cycling with constant stress amplitudes. Natural cracks nucleated in specimens made from an extruded bar whose axis was parallel with the extrusion direction. Due to anisotropy of the extruded bar the nucleation rate and the initial crack growth rate on two sides of the specimen differ substantially. Natural cracks initiate frequently on the non-metallic inclusions. The texture has a substantial effect on the initiation and early crack growth. The cracks grow along the slip bands in which cyclic plastic strain is localised. The kinetics of short crack growth was measured and determined in relation with the structural anisotropy of the material. The kinetics of short crack growth follows the exponential law.

Key words
aluminum-lithium alloy, fatigue crack initiation, short crack growth, anisotropy

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