The composition dependence of the effective vacancy formation enthalpy in copper-rich brass as deduced from the threshold temperature for positron trapping in vacancies

The temperature dependence of the Doppler-broadened positron annihilation lineshape has been measured for 13 brass specimens with compositions varying from 0 to 48% by weight of Zn. The vacancy formation enthalpy deduced from these measurements shows a linear decrease of 22% with increasing Zn concentration through the α phase and a further 31% decrease on changing from fcc to bcc structure.