Dynamic Model for Formation of Twinned Martensite Crystals

TL;DR

This paper proposes a dynamic model for the formation of twinned martensite crystals, emphasizing the role of both long and short waves in controlling twin structure growth during rapid crystal transformation.

Contribution

It introduces a novel dynamic model incorporating wave interactions to explain the formation and growth of twinned martensite crystals at high growth rates.

Findings

Model aligns with experimental morphological data

Identifies optimal twin structure ratios for minimal transformation time

Explains transition to large final deformations

Abstract

Based on original investigations into the stages of nucleation and growth of martensite, a consideration has been given to dynamic models of formation of martensite plates with a fine structure of transformation twins, which are compatible with the supersonic growth rate of martensite crystals. Along with relatively long quasi-longitudinal waves, which determine the orientation of the habit plane, the control wave process includes relatively short longitudinal waves, which act in synchronism and control the growth of the main component of a regular twin structure. Preference is given to a model containing, at the initial moment of time, the only active dynamic cell capable of periodic reproduction in the interphase region at the stage of the martensite crystal growth. Conditions providing the ratio between the components of the twin structure, which would be optimal for minimization of the transformation time, have been discussed. A transition to final deformations, which are two to three orders of magnitude larger than the threshold deformations, have been made. The calculated macroscopic morphological attributes, which were deduced from dynamic considerations, have been compared with the experimental data and crystallogeometrical calculation.