We present a microscopic model that explains quenching of the magnetization of ferromagnetic transition metals such as nickel within a picosecond after laser excitation. Our model describes the interactions between a Fermi sea of (spinless) electrons, an ensemble of two level oscillators representing the phonon system, and a magnetic degree of freedom described by the Weiss model. An Elliot–Yafet type of spin-flip probability αEY is included for each electron–phonon (e–p) scattering event. We show that even though the demagnetization in our model is mediated by phonon scattering, it is possible to obtain a demagnetization time that is shorter than the e–p equilibration (and even thermalization) time.