Comparison between frictional behavior of the soft and brittle materials at different contact pressures.

Abstract

Coefficient of friction changed significantly by the change in contact pressure. Experimental measurement of the coefficient of friction in different contact pressures can be useful in numerical and analytical analysis of many engineering problems, such as metal forming process. This study dedicated to investigate the sensitivity of the friction coefficient to changes in contact pressures. To aim this goal the special tribometer device has been fabricated and the coefficient of friction of the soft and brittle metals when sliding with a low speed on a rigid body are measured for different contact pressures. The friction sensitivity of the soft (copper and aluminum) and brittle (steel) samples to changes in contact pressure are compared and discussed. The results showed that both brittle and soft metals are highly sensitive for change in contact pressure but their behaviour is slightly different. While the coefficient of friction of the steel sample when sliding on a steel substrate is reduced sharply by a little increase in contact pressure; the coefficient of friction of the soft material when sliding on a steel substrate is reduced slowly depending on the magnetude of the applied normal load.