The Correlation of Machinability and Microstrutural Characteristics of Different Extruded Aluminum Alloys

This work correlates metallurgical characteristics (chemical composition, microstructure and morphology of second phase particles) of different extruded aluminum alloys with their machinability as determined by the measurement of axial forces and shear momentum involved in drilling operations. Three different aluminum alloys were evaluated. The alloy AA6061 with low and high P content was tested in the recrystallized condition while alloys AA6351 and AA2117 were tested in the cold-worked condition. Specimen characterization also included tensile and hardness tests, chemical and microstructural evaluation. The results have shown that Pb and Cu have a positive effect on the machinability of these alloys and that the microstructure control may decrease forces in machining, resulting in great improvement of production in cutting procedures.