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Besides permitting an accurate determination of the ferromagnetic-to-paramagnetic phase transition temperature and the characteristic temperatures for the beginning and end of the growth of martensite (austenite) phase at the expense of…
Ferromagnetic shape memory alloys Ni$_{2+x}$Mn$_{1-x}$Ga were studied in the range of compositions $0.16 \le x \le 0.36$. Experimental phase diagram, constructed from differential scanning calorimetry, transport and magnetic measurements,…
A three-dimensional phase-field model is proposed for simulating the magnetic martensitic phase transformation. The model considers a paramagnetic cubic austenite to ferromagnetic tetragonal martensite transition, as it occurs in magnetic…
When a crystalline solid such as iron is cooled across a structural transition, its final microstructure depends sensitively on the cooling rate. For instance, an adiabatic cooling across the transition results in an equilibrium `ferrite',…
The irreversibility of the martensite transition in magnetic shape memory alloys (MSMAs) with respect to external magnetic field is one of the biggest challenges that limits their application as giant caloric materials. This transition is a…
To understand how martensitic transformation (MT) in polycrystalline NiTi shape memory alloy (SMA) proceeds under external stress, we evaluated recoverable transformation strains and plastic strains generated by the forward MT in…
The main purpose of this study is to determine, via a three dimensions Finite Element analysis (FE), the stress and strain fields at the inner surface of a tubular specimen submitted to thermo-mechanical fatigue. To investigate the surface…
We describe magneto-, baro- and elastocaloric effects (MCEs, BCEs and eCEs) in materials which possess both discontinuous (first-order) and continuous (second-order) magnetic phase transitions. Our ab initio theory of the interacting…
Functional behavior of NiTi shape memory alloys is restricted to temperatures below 150 {\deg}C. To shed light on the origin of the loss of functional properties of NiTi with increasing temperature, we have investigated stress induced…
Ferroic materials enable a multitude of emerging applications, and optimum functional properties are achieved when ferromagnetic and ferroelectric properties are coupled to a first-order ferroelastic transition. In bulk materials, this…
Superelastic NiTi 1 shape memory alloy (SMA) wire was subjected to thermomechanical loading tests in tension to evaluate stress and temperature conditions under which the wire deforms plastically. Although the alloy demonstrated a very high…
Purpose: The purpose of this work is to apply a recently proposed constitutive model for mechanically induced martensitic transformations to the prediction of transformation loci. Additionally, this study aims to elucidate if a…
Phase transition is a fundamental phenomenon in condensed matter physics, in which states of matter transform to each other with various critical behaviors under different conditions. The magnetic martensitic transformation features…
Diffusionless phase transitions are at the core of the multifunctionality of (magnetic) shape memory alloys, ferroelectrics and multiferroics. Giant strain effects under external fields are obtained in low symmetric modulated martensitic…
Shape memory alloys are a class of ferroic materials which undergo a structural (martensitic) transition where the associated ferroic property is a lattice distortion (strain). The sensitiveness of the transition to the conjugated external…
We use the phase-field method to study the martensitic transformation at the nanoscale. For nanosystems such as nanowires and nanograins embedded in a stiff matrix, the geometric constraints and boundary conditions have an impact on…
We report magnetization and differential thermal analysis measurements as a function of pressure accross the martensitic transition in magnetically superelastic Ni-Mn-In alloys. It is found that the properties of the martensitic…
While most phase transformations, e.g. ferroelectric or ferromagnetic, can be first or second order depending on external applied fields, martensitic transformations in metallic alloys are nearly universally first order. We demonstrate that…
Multiferroic materials have undergone extensive research in the past two decades in an effort to produce a sizable room-temperature magneto-electric (ME) effect in either exclusive or composite materials for use in a variety of electronic…
The degenerate Blume-Emery-Griffiths model for martensitic transformations is extended by including both structural and magnetic degrees of freedom in order to elucidate premartensitic effects. Special attention is paied to the effect of…