Fig. 1: Maps of the deviatoric strain of the B2 austenite along the vertical y axis (εyy) from x-ray diffraction analysis. The global displacements for these maps are shown in the upper left corner of each image. The dark lines illustrate the approximate location of the edges of the diamond strut. The red color indicates tensile strain whereas blue indicates compressive strain; note also the pr...

A method based on the kinetics of crystal growth has been developed and applied to the computation of three-dimensional microstrucuture in austenite-matensite steels. The detailed crystallography of the transformation is used to model a realistic martensitic microstrucuture during the transformation without an external system of stresses. The interaction energy based on the plastic work model i...

The objective of this work was to study materials subjected to external loading where alternative deformation mechanisms are available to generate strains. In the case of shapememory and superelastic NiTi, these mechanisms are twinning and stress-induced phase transformation, respectively. Superelastic NiTi (51.0 at.% Ni) reinforced with 0, 10 and 20 vol.% TiC particles was fabricated by Hot Is...

The effects of a high-velocity impact on the microstructure, phase transformation and mechanical property of aged Ti49Ni51 alloy are investigated. The transformation behavior and microstructure along the impact direction after impact emerge with regionalization characteristics, including a deformed region near the crater (0-4 mm) and an un-deformed region of the distal crater (5-6 mm). Stress-i...

Two stage austenite ??-martensite ??-martensite phase transformation, phase-specific lattice strain evolution and load sharing during tensile deformation of a 13%Mn hot-rolled austenitic steel are revealed by in-situ neutron diffraction. Direct evidence is provided that serrated behavior attributed to discontinuous martensitic transformation.

Titanium-based shape memory alloys undergo a cubic to orthorhombic martensitic transformation (β to α’’ martensite). A new easy way operating as a reconstruction of the parent microstructure is used from electron backscattered diffraction. It is shown that the electron backscattered patterns of the martensitic microstructure can be directly indexed as the parent phase in order to obtain the cor...

Thermodynamically consistent, three-dimensional (3D) phase field approach (PFA) for coupled multivariant martensitic transformations (PTs), including cyclic PTs, variant– variant transformations (i.e., twinning), and dislocation evolution is developed at large strains. One of our key points is in the justification of the multiplicative decomposition of the deformation gradient into elastic, tra...