Modeling of friction behaviour during in temperature compression tests on aluminium alloys

摘要

In the context of the in temperature deformation of aluminium alloys, the information related to the friction acting at the tool-workpiece contact interface is very useful. This produces an increase in the energy required for deformation. In practice, the friction levels can affect the loads required to get given deformations. But, the friction acts sometimes also as a guide of the flow material inside the workpiece and then of the deformation itself. The present investigation aims at studying in depth and at modeling the effect of the friction during in temperature deformations on the flow behaviour of a composite aluminium alloy previously deformed at room temperature. In detail, cylindrical specimens were pre-deformed under two different conditions in order to get two different hardening situations. The specimens under such conditions were subsequently deformed in the temperature interval of 200 - 300°C by compression tests. Different constant deformation velocities varying in the interval 0.001 - 0.01 1/s were used. The comparison between the flow curve shapes obtained considering the friction and those without friction, got supposing an uniform deformation of the specimens during the tests, was made. It was observed a decrease in the friction contribution with increasing the temperature and with increasing the pre-deformation levels. The modeling of the flow curves and of their friction behaviour is reported.