Parallel edge cracks due to a phase transformation

We study the nucleation and propagation of parallel cracks in the wake of a solid–solid phase boundary. Our results are also applicable to situations where one has a sharp change of concentration or temperature. We identify conditions on the transformation strain when we expect parallel edge cracks. We show that cracks have little affect on the overall evolution of the phase boundary. We also show that cracks nucleate when the phase boundary has propagated a certain distance from the free edge. The cracks have uniform spacing and their tips reach slightly beyond the phase boundary. Subsequently all cracks propagate with the propagating phase boundary in such a manner that the spacing remains uniform and the tips reach just beyond the phase boundary. Importantly, we show that there is no period-doubling or other instabilities common to thermal cracking when the gradient is small.