The strong influence of internal stresses on the nucleation of a nanosized, deeply undercooled melt at a solid-solid interface
Kasra Momeni, Valery I. Levitas, James A. Warren
The effect of elastic energy on nucleation and disappearance of a nanometer size intermediate melt (IM) region at a solid-solid (S1S2) interface at temperatures 120K below the melting temperature is studied using a phase- field approach. Results are obtained for broad range of the ratios of S1S2 to solid-melt interface energies, kE, and widths, k. It is found that internal stresses only slightly promote barrierless IM but qualitatively alter the system behavior, allowing for the appearance of the IM when kE < 2 (thermodynamically impossible without mechanics) and elimination of what we termed the IM-free gap. Remarkably, when mechanics is included within this framework, there is a drastic (16 times for HMX energetic crystals) reduction in the activation energy of IM critical nucleus. Under these conditions, a kinetic nucleation criterion is met, and thermally activated melting occurs under conditions consistent with experiments for HMX, elucidating what had been, to-date, mysterious behavior.
Intermediate melt, phase field approach, solid-melt-solid interface, nucleation, internal stresses
, Levitas, V.
and Warren, J.
The strong influence of internal stresses on the nucleation of a nanosized, deeply undercooled melt at a solid-solid interface, Nano Letters
(Accessed March 2, 2024)