Abstract: Wear and fracture mechanisms are revealed in high- speed milling aluminium alloy 7050-T7451 based on experimental and theoretical research. A new method is presented to reveal crack initiation of cutting tool by impulse laser simulation. The different roles of milling forces and thermal stress in tool failure are studied. The results prove that crack initiation is caused by thermal stress while is expanded by thermal and mechanical stresses in high speed milling aluminium alloy 7050-T7451. Failure mechanisms are investigated and adhesive and diffusion are main wear mechanisms. To decrease the impact of mechanical stress on milling tools, measures are presented that stability of machining system should be tested and cutting parameters should be optimized, which have been employed in workshop and the fact prove that tool breakage decrease remarkably.

Key words: Aluminum alloy, Failure mechanism, High-speed milling, Tool wear