Energy and morphology of martensite-twinned martensite interface in CuAlNi shape memory alloy: a phase-field study

TL;DR

This study uses a phase-field model to analyze the microstructure and energy of the martensite-twinned martensite interface in CuAlNi shape memory alloys, focusing on size effects and twin branching phenomena.

Contribution

It introduces a phase-field approach to simulate and analyze the morphology and energy of the interface in shape memory alloys, highlighting size-dependent effects and twin branching mechanisms.

Findings

Twin branching occurs at certain twin volume fractions to minimize energy.

Twin spacing significantly influences the morphology of the transition layer.

The phase-field model effectively captures size-dependent microstructural features.

Abstract

Needle-like twins are observed experimentally within the transition layer at the martensite-twinned martensite interface. We utilize a phase-field approach to investigate this microstructure. Our goal is to simulate the morphology of the transition layer and to perform a detailed analysis to characterize its interfacial and elastic micro-strain energy. To illustrate the micromechanical framework developed for that purpose, sample computations are carried out for a CuAlNi shape memory alloy undergoing the cubic-to-orthorhombic martensitic transformation. A particular focus of the study is on size-dependent morphology through examining the impact of twin spacing. Additionally, our results reveal that certain twin volume fractions lead to the emergence of twin branching, as a way to minimize the total free energy stored in the microstructure.