Mechanical damping in leaded and in lead-free alpha brass

Abstract

Using the piezoelectric composite oscillator at 40kHz and strain amplitude of 2.7 × 10 −7−5.5 × 10 −6 we have measured the mechanical damping of leaded and lead free alpha brass at 25–400°C. We observed in the leaded brass on heating a decrease in mechanical damping starting at 319°C followed by a sharp peak at 327°C and on cooling an increase in damping starting at 305°C and reaching the original damping values for heating at 280°C. We attribute these effects to the melting and redistribution of lead since no such effects were observed in the lead-free brass.