The effect of Nb on the hydrogen embrittlement susceptibility of Q&P steel under static and dynamic loading

In the present study, the effect of Niobium (Nb) on the hydrogen embrittlement resistance of Quenched and Partitioning (Q&P) steel is investigated. For this purpose, the hydrogen uptake level and its impact on the mechanical properties of a Nb-free and a 0.024 wt% Nb Q&P steel are thoroughly analysed. The hydrogen trapping capacity is...

Effect of the anisotropy of martensitic transformation on ferrite deformation in Dual-Phase steels

The volume increase and shape change during austenite to martensite transformation in dual-phase (DP) steels are largely accommodated in the microstructure by the deformation of the surrounding ferrite matrix. Accurate estimation of transformation-induced deformation of ferrite via experiments and modeling is essential for predicting the...

Atomistic Simulations of Nickel-Titanium Shape-Memory Alloys

Shape-memory Alloys (SMAs) exhibit tremendous mechanical properties owing to their reversible phase transformation between the austenitic and the martensitic phase. Out of these, equi-atomic nickel-titanium (NiTi) alloys are the most widely used SMAs for various applications since the transformation occurs close to room temperature. Advances in...

Effect of C on the martensitic transformation in Fe-C alloys in the presence of pre-existing defects: A molecular dynamics study

Molecular dynamics simulations are used to investigate the atomic effects of carbon (C) addition in Fe on the martensitic phase transformation in the presence of pre-existing defects such as stacking faults and twin boundaries. The pre-existing defect structures in Fe-C alloys have the same effect on the atomistic mechanisms of martensitic...

Effect of pre-existing defects in the parent fcc phase on atomistic mechanisms during the martensitic transformation in pure Fe: A molecular dynamics study

Molecular dynamics (MD) simulations are used to study the effect of different defect configurations and their arrangements in the parent fcc phase on atomistic mechanisms during the martensitic transformation mechanisms in pure Fe. The defect configurations considered are stacking faults (SF) and twin boundaries (TB) in single crystal fcc. Three...

Molecular dynamics simulations of fcc-to-bcc transformation in pure iron: a review

Molecular dynamics (MD) simulation has been used to study the martensitic transformation in iron at the atomic scale. The paper reviews the available interatomic interaction potentials for iron, which describe the properties of different phases present in that system. Cases on the fcc-to-bcc transformation in iron by MD simulations were...

Metastable Beta Titanium Alloys: Tuning the Beta Phase Stability and Low-Temperature Martensitic Transformation of Metastable Beta Titanium Alloys

This research focuses on the stability of three metastable ? titanium alloys – Ti-10V-1Fe-3Al (Ti-1013), Ti-10V-2Cr-3Al (Ti-102Cr3) and Ti-10V-2Fe-3Al-B (Ti-1023B). In the first stage of the work, new ?+(?+?) heat treatment schemes were designed on the basis of Thermo-Calc® simulations and previous research work and carried out to such an extent...

Orientation dependence of the martensite transformation in a quenched and partitioned steel subjected to uniaxial tension

The orientation dependence of the austenite-to-martensite transformation during uniaxial tensile testing was modelled using the phenomenological theory of martensite crystallography and the mechanical driving force. It was validated experimentally by means of electron backscatter diffraction measurements on a pre-defined zone of a quenched and...

High-resolution X-ray diffraction investigation on the evolution of the substructure of individual austenite grains in TRIP steels during tensile deformation

The martensitic transformation behaviour of the metastable austenite phase in low-alloyed transformation-induced plasticity (TRIP) steels has been studied in situ using high-energy X-ray diffraction during deformation. The austenite stability during tensile deformation has been evaluated at different length scales. A powder diffraction analysis...

Position-dependent shear-induced austenite– martensite transformation in double-notched TRIP and dual-phase steel samples

While earlier studies on transformation-induced-plasticity (TRIP) steels focused on the determination of the austenite-to-martensite decomposition in uniform deformation or thermal fields, the current research focuses on the determination of the local retained austenite-to-martensite transformation behaviour in an inhomogeneous yet carefully...

Unravelling the structural and chemical features influencing deformation-induced martensitic transformations in steels

A combination of Electron Back-Scattered Diffraction (EBSD) and high-sensitivity Electron Probe Micro-Analysis (EPMA) was used to correlate the changes in microstructural features upon deformation with local chemical composition in Transformation-Induced Plasticity steels. A novel cleaning procedure was developed that allows complete monitoring...

Tailoring the Mechanical Properties of Titanium Alloys via Plasticity Induced Transformations

Titanium alloys possess good corrosion properties, high temperature stability and high strength-to-weight ratio. However, they fall short in providing the optimum strength-ductility relation in the most demanding structural applications, including the aerospace sector. Inspired by the possibility of enhancing the strength-ductility relation in...

Tailoring the mechanical properties of titanium alloys via plasticity induced transformations

Titanium alloys possess good corrosion properties, high temperature stability and high strength-to-weight ratio. However, they fall short in providing the optimum strength-ductility relation in the most demanding structural applications, including the aerospace sector. Inspired by the possibility of enhancing the strength-ductility relation in...

Discrete Modelling of Plasticity and Martensitic Transformations

Micromechanical modeling and simulations of transformation-induced plasticity in multiphase carbon steels