  One of the most important scaling laws of time dependent fracture is
Basquin's law of fatigue, namely, that the lifetime of the system increases as
a power law with decreasing external load amplitude, $t_f\sim
\sigma_0^{-\alpha}$, where the exponent $\alpha$ has a strong material
dependence. We show that in spite of the broad scatter of the Basquin exponent
$\alpha$, the fatigue fracture of heterogeneous materials exhibits intriguing
universal features. Based on stochastic fracture models we propose a generic
scaling form for the macroscopic deformation and show that at the fatigue limit
the system undergoes a continuous phase transition when changing the external
load. On the microlevel, the fatigue fracture proceeds in bursts characterized
by universal power law distributions. We demonstrate that in a range of
systems, including deformation of asphalt, a realistic model of deformation,
and a fiber bundle model, the system dependent details are contained in
Basquin's exponent for time to failure, and once this is taken into account,
remaining features of failure are universal.
