Creep crack propagation in gold submicron films at room temperature

We conducted creep crack propagation experiments on Au freestanding films of 400 nm thickness at room temperature to determine the dominant fracture mechanics parameter. In the experiments, a crack stably propagated accompanied by creep deformation, and it was found that the crack propagation rate $$\hbox {d}a/\hbox {d}t$$ was neither uniquely characterized by the stress intensity factor nor the net stress. Furthermore, the steady-state creep J-integral $$J_s^*$$ was estimated by an approximate equation using the experimental crack center opening displacement, and the $$\hbox {d}a/\hbox {d}t-J_s^*$$ relations were observed within a narrow band irrespective of the specimen width and applied stress. The results indicated that the creep J-integral is the dominant mechanical parameter that characterizes the creep crack propagation rate in Au films.