Dataset of a thermal model for the prediction of temperature fields during the creation of austenite/martensite mesostructured materials by localized laser treatments in a Fe-Ni-C alloy

This work presents constitutive equations and a dataset of a thermal model for the prediction of temperature fields and heating rates during the application of localized laser treatments to a Fe-C-Ni alloy. The model considers transient material properties and the coupling between temperature and microstructure, with emphasis on the phase...

Engineering austenite/martensite mesostructured materials by controlled localised laser treatments in a Fe–Ni–C alloy

Localised laser treatments enable the creation of sophisticated austenite/martensite mesostructures in Fe–Ni–C steel with the potential of achieving enhanced mechanical performance. The control of phase topology is essential to modify the properties of these structures on demand and requires a profound understanding of the effect of the...

A Data-Driven Approach for Studying the Influence of Carbides on Work Hardening of Steel

This study proposes a new approach to determine phenomenological or physical relations between microstructure features and the mechanical behavior of metals bridging advanced statistics and materials science in a study of the effect of hard precipitates on the hardening of metal alloys. Synthetic microstructures were created using multi-level...

Role of planar faults in martensite formation in nano-polycrystalline iron by molecular dynamics simulation

The martensitic transformation in pure Fe and its alloys has been studied over many decades. Several theoretical models have been proposed to describe the atomic motion that leads to the fcc-to-bcc martensitic transformation. However, such models do not account for the effect of pre-existing planar defects such as twin boundaries and stacking...

Hierarchically patterned multiphase steels created by localised laser treatments

The realisation of sophisticated hierarchically patterned multiphase steels has the potential to enable unprecedented properties in engineering components. The present work explores the controlled creation of patterned multiphase steels in which the patterns are defined by two different crystal structures: face centre cubic or fcc (austenite)...

The role of plastic strains on variant selection in ausformed bainitic microstructures studied by finite elements and crystal plasticity simulations

The mechanisms driving variant selection phenomena in ausformed bainitic microstructures are not fully controlled yet. Previous results are not congruent among them, as they cannot be explained by the same rule. In this work, we aimed to understand the mechanisms governing variant selection in a medium carbon-high silicon steel subjected to...

Isotonic regression for metallic microstructure data: Estimation and testing under order restrictions

Investigating the main determinants of the mechanical performance of metals is not a simple task. Already known physically inspired qualitative relations between 2D microstructure characteristics and 3D mechanical properties can act as the starting point of the investigation. Isotonic regression allows to take into account ordering relations...

Assessing the scale contributing factors of three carbide-free bainitic steels: A complementary theoretical and experimental approach

The bainitic ferrite plate thickness is the main parameter that controls the strength of this type of microstructures. Such thickness has been proved to mainly depend on the austenite yield strength, the driving force for the transformation and the transformation temperature. However, no research has focused on how these parameters evolve...

Unravelling the mechanical behaviour of advanced multiphase steels isothermally obtained below M_s

The initial formation of athermal martensite was proven to accelerate the subsequent bainite formation kinetics during isothermal holdings below the martensite-start temperature (M_s). The presence of prior athermal martensite (PAM) within the phase mixture is expected to modify the overall mechanical response of these newly...

Influence of M₂₃C₆ carbides on the heterogeneous strain development in annealed 420 stainless steel

Understanding the local strain enhancement and lattice distortion resulting from different microstructure features in metal alloys is crucial in many engineering processes. The development of heterogeneous strain not only plays an important role in the work hardening of the material but also in other processes such as recrystallization and...

Use of the Correlation between Grain Size and Crystallographic Orientation in Crystal Plasticity Simulations: Application to AISI 420 Stainless Steel

Crystal plasticity models attempt to reproduce the complex deformation processes of polycrystalline metals based on a virtual representation of the real microstructure. When choosing this representation, a compromise must be made between level of detail at the local level and statistical significance of the aggregate properties, also taking into...

Interplay between metastable phases controls strength and ductility in steels

By means of high-energy synchrotron X-ray diffraction, the interplay between martensite and retained austenite phases in steel during the application of stress has been analyzed. Martensite properties were varied through controlled reheating heat treatments in a low carbon Quenched and Partitioned (Q&P) steel consisting of retained...

Fracture mechanisms and microstructure in a medium Mn quenching and partitioning steel exhibiting macrosegregation

A medium-Mn steel, exhibiting manganese macrosegregation, was investigated. In order to study how the microstructure development influences the fracture mechanisms, the steel was quenching and partitioning processed using two different partitioning temperatures. At 400 °C partitioning temperature, the microstructure exhibits intergranular...

Influence of the prior athermal martensite on the mechanical response of advanced bainitic steel

The accelerated formation of bainite in presence of martensite is opening a new processing window for the steel industry. However, for a feasible industrial implementation, it is necessary to determine the mechanical behaviour of the steels developed under such conditions. This study focuses on analysing the effects of the formation of...

Thermal and mechanical stability of retained austenite surrounded by martensite with different degrees of tempering

The mechanical and thermal stability of austenite in multiphase advanced high strength steels are influenced by the surrounding microstructure. The mechanisms underlying and the relations between thermal and mechanical stability are still dubious due to the difficulty of isolating other factors influencing austenite stability. In this work,...

Controlling the work hardening of martensite to increase the strength/ductility balance in quenched and partitioned steels

The role of retained austenite on tensile behavior in quenched and partitioned (Q&P) steels has been studied extensively, but the deformation behavior of martensite, which comprises the majority of Q&P microstructures, has received less attention. In this investigation, martensite properties were varied through heat treatment in a low...

Characterization of bainitic/martensitic structures formed in isothermal treatments below the M_s temperature

Advanced Multiphase High Strength Steels are generally obtained by applying isothermal treatments around the martensite start temperature (M_s). Previous investigations have shown that bainitic ferrite can form from austenite in isothermal treatments below M_s, where its formation kinetics is accelerated by the presence of...

Effect of prior austenite grain size refinement by thermal cycling on the microstructural features of as-quenched lath martensite

Current trends in steels are focusing on refined martensitic microstructures to obtain high strength and toughness. An interesting manner to reduce the size of martensitic substructure is by reducing the size of the prior austenite grain (PAG). This work analyzes the effect of PAGS refinement by thermal cycling on different microstructural...