Łukasz Madej

• Professor
• Professor (Full) at AGH University of Krakow

We summarize a data analysis approach for electron backscatter diffraction (EBSD) which uses high-resolution Kikuchi pattern simulations to measure isochoric relative deformation gradient tensors from experimentally measured Kikuchi patterns of relatively low resolution. Simulation-based supersampling of the theoretical test diffraction patterns en...

Explosive welding (EXW) is a high-speed process used to join dissimilar materials and produce large surface sheet products. While traditionally reliant on experimental observations of welded interfaces, this approach offers limited insight into the dynamic phenomena during flyer and base plate collisions, hindering the development of closed-loop co...

Dynamic recrystallisation (DRX) is one of the fundamental phenomena in materials science, significantly impacting the microstructure and mechanical properties of components subjected to large plastic deformations. Experimental research on that topic carried out for a wide range of new metallic materials is often supported by computational materials...

The process of explosive welding offers very attractive capabilities of joining dissimilar materials, but at the same time, it is a highly intricate and advanced technology involving a multitude of phenomena occurring in the colliding plates in a matter of microseconds. In this case, numerical modeling can greatly support understanding local materi...

The mechanical properties of materials can be analysed under deformation conditions by various laboratory tests. However, such experimental investigations become extremely complicated and often even impossible at the lower length scales where the arrangement of the atomic planes is considered. In this case, computational materials science is a robu...

Full-field simulations used to enhance the predictive capability of classical finite element models require the preparation of high-quality initial digital material representation (DMR) data. Depending on the selected method, such a procedure can be time-consuming and, in subsequent model runs, result in a significant increase in computational time...

A multi-scale numerical investigation of local heterogeneities in the strain and stress fields occurring during forming of explosively welded layered metallic sheets is the main goal of the research. Explosive welding is a complex process involving various phenomena occurring in materials during an impact at high velocities and pressures, especiall...

The evolution of metallic material microstructures under thermo‐mechanical treatment is a critical element that influences the in‐use properties of the final product. In the last four decades, many researchers around the world focused on reliable numerical recreation of phenomena that occur during metal processing. Particular attention was put on t...

The aim of this work is to develop an automated procedure based on machine learning capabilities for the identification of the pearlite islands within the two-phase pearlitic-ferritic steel. The input parameters for the custom implementation of a braided neural network are provided as a data set of scanning electron microscopy images of metallograp...

The extraordinary combination of strength and ductility of multilayered materials makes them attractive in the various applications and industries (military, aerospace, energy industry etc.). In the present work, the investigated materials were joined into multilayered sheet using the explosive welding method. The three-layer material was made of t...

Determination of the influence of grain boundary curvature model type on the cellular automata (CA) static recrystallization (SRX) simulation predictions is the primary goal of the research. The developed CA model is a full-field approach that captures local heterogeneities in grain morphology, crystallographic orientation, and distribution of stor...

The simulation of manufacturing processes has significant importance. The research and development of metal forming simulation started in the 1960s from the elastoplastic analysis of a simple plastic deformation, and it now covers a wide range of forming processes. The accuracy and applicability of metal forming simulation have significantly progre...

The computer-aided development of the leveling technology for high-strength steel flat sheet products is the primary goal of the research. The roll leveler setups are evaluated from the final product point of view with an acceptable flatness level and stress state at the same time. First, a reliable hardening model is developed based on experimenta...

Development of the descriptors of the multiphase microstructure, which will allow comparing materials local fracture resistance, was the objective of the paper. A hypothesis was made that local gradients of properties can realistically represent the tendency to the local fracture and can be an effective indicator for the stretch‐flangeability prope...

Screens made of drawn and spot-welded stainless steel precise profile wires are widely used to separate particles from fluids during various industrial applications. Increased durability and surface quality of these products are critical in maximising their wear resistance and extending the screen service life. Therefore, the paper discusses the de...

This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book focuses on modelling of processing of materials and that it combines the problem of multiscale modelling with the optimization tasks providing a wide range of possibilities for practical industrial applications. It provides a prese...

The modelling of discontinuities is playing a more critical role in analyzing material behaviour during plastic deformation. The macroscale model uses a two‐dimensional rigid‐plastic method that provides the boundary conditions for the microscale model. As a result of the microscale simulation, the friction coefficient is modified in the macroscale...

This chapter describes the major physical phenomena responsible for material behaviour under manufacturing and exploitations stages. It describes the limitations of conventional modelling approaches and introduces possibilities provided by the multiscale solutions. The chapter discuses nanoscale and microscale phenomena, including quantum scale, an...

This chapter reviews programming libraries and available software, which allow visualizing various datasets. It shows an idea and implementation details of a computer application that supports visualization of datasets exceeding the capabilities of the hardware. The chapter presents a review of graphical libraries allowing a flexible implementation...

This chapter describes the useful computational methods for multiscale modelling and optimization. It also describes the two most commonly used methods: finite element method (FEM) and boundary element method (BEM) in the multiscale context. The chapter explains the new method extended FEM to describe the variety of available numerical methods. It...

This chapter is devoted to innovative approaches to numerical modelling, taking into account different nanoscale or microscale features explicitly during simulation with the numerical methods. It detains different approaches to the generation of nanostructures and microstructures for subsequent numerical calculations. The chapter describes the meth...

This chapter is devoted to selected optimization and identification problems in the case of multiscale modelling. The optimization in multiscale modelling allows finding structures with better performance or strength in one scale with respect to design variables for another scale. The chapter presents the process of minimization of the potential en...

The last decades have seen several attempts to develop Severe Plastic Deformation (SPD) processes to manufacture parts with Ultra-Fine Grained (UFG) microstructure without additional thermal processing. However, they remained mostly focused on producing small components, often in the micro-scale range, thus limiting the technological and environmen...

During static recrystallization, grains often have non-constant and non-uniform growth rates, significantly affecting the recrystallization kinetics and the microstructure after recrystallization. A cellular automaton model was employed in order to evaluate the relative influences of gradients of stored energy, grain boundary curvature, and heterog...

Herein, we evaluate the nanoindentation test capabilities in the determination of flow stress characteristics of the matrix material in porous sinters. The Distaloy AB sample with 15% porosity after the sintering operation is selected as a case study for the investigation. 2D and 3D imaging techniques are employed first to highlight difficulties in...

Local variations in chemical composition, i.e., compositional heterogeneities, play an important role in the thermodynamic stability and spatial distribution of phases in multiphase steels. The influence of heterogeneous elemental distribution on the resulting local microstructure and mechanical properties has been investigated in the present work....

The paper's main interest is the identification and elimination of major factors that can introduce disturbances in the predictions of the cellular automata (CA) static recrystallization (SRX) model. First, the most important CA SRX model components and major assumptions are shortly presented. Next, the determination of appropriate CA cell size, wh...

An attempt to bridge the gap between capabilities offered by advanced full-field microstructure evolution models based on the cellular automata method and their practical applications to daily industrial technology design was the goal of the work. High-performance parallelization techniques applied to the cellular automata static recrystallization...

Perceptive review of augmented reality applications in the forging industry is the primary goal of the paper. The differences between the Virtual (VR) and Augmented (AR) realities are highlighted first. Examples of the AR technology's various industrial applications are then presented, which is followed by the evaluation of capabilities of the appr...

The development of an efficient numerical approach for the generation of a wide range of heterogeneous microstructures models with the application of the lean workflow concept is presented in the paper. First, the idea and implementation details of the developed cellular automata-based computational library allowing the development of digital mater...

The development and identification of the complex microscale austenite to ferrite transformation model during continuous cooling based on the Cellular Automata method and DigiCore library is the main goal of the work. The model is designed to predict phase transformation from a fully austenitic range and involves nucleation of ferrite grains with t...

A novel criterion for microcrack resistance of multi-phase steels based on property gradient maps is proposed. Two industrial sheets of steel were processed to obtain dual-phase and complex-phase microstructures with exactly the same chemical composition. Experimental investigations showed characteristic differences for the tensile tests, hole expa...

Numerical study of the influence of pulsed laser deposited TiN thin films’ microstructure morphologies on strain heterogeneities during loading was the goal of this research. The investigation was based on the digital material representation (DMR) concept applied to replicate an investigated thin film’s microstructure morphology. The physically bas...

The porosity characteristics of sintered specimens, made of the Distaloy AB powder, subjected to various deformation modes have been examined within the work. The sintering technological parameters were adjusted to obtain 15% volume fraction of pores. The sintered specimens were plastically deformed by conventional uniaxial compression, compression...

The paper focuses on adapting the random cellular automata (RCA) method concept for the unconstrained grain growth simulation providing digital microstructure morphologies for subsequent multi-scale simulations. First, algorithms for the generation of initial RCA cells alignment are developed, and then the influence of cells density in the computat...

The experimental and numerical study of the effects of the recrystallization behavior of austenite model alloys during hot plate rolling on reverse rolling is the main goal of the paper. The computer models that are currently applied for simulation of reverse rolling are not strain-path-sensitive, thus leading to overestimation of the processing pa...

In this study, large-scale molecular dynamic simulations were performed to analyze the dislocation substructure interaction with various types of obstacles present in microalloyed steels during severe plastic deformation. Specifically, fully functional numerical models of the atomic upsetting test were developed, with particular emphasis on the pre...

The implementation of a dedicated communication mechanism between micro- and macroscale models of the fully coupled multiscale numerical approach is the topic of the paper. The presented solution is based on the System V IPC message queue that is part of modern Linux-based operating systems. Developed and implemented approach is validated with a se...

In this work, the competition between various hardening and softening processes in explosively welded (EXW) and post-annealed Ti/Cu composites was studied using scanning and transmission electron microscopy, mechanical testing and numerical modelling. The mesh-free numerical model appropriately reproduces the formation of a wave-like morphology, in...

The paper shows the feasibility of manufacturing surgical clips using bioabsorbable AZ31B magnesium alloy strips characterized by enhanced forming characteristics, and, at the same time, improved corrosion resistance to human fluids that make them suitable for temporary applications. The novel process chain used for the clip manufacturing includes...

Development and verification of a parallel version of the micro-scale cellular automata (CA) static recrystallization (SRX) model is the main goal of the present research. Firstly, a framework of sequential CA-SRX model is presented. Then, crucial modifications are developed and introduced to the model to handle parallel execution. A particular att...

Preparation of a reliable 3D digital material representation model, for further finite element formability calculations, based on series of 2D images from serial sectioning procedure is the main goal of the paper. Within the work series of 2D SEM/SE2 images of a ferrite-pearlite microstructure were accompanied by an EBSD investigation to clearly id...

Innovative incremental bulk forming (IBF) process dedicated to form integral elements for the aerospace industry is presented in the paper. Particular attention is put on analysis of advantages and disadvantages of this process, as well as on detailed evaluation of material flow characteristics across different length scales. Thus, a multi scale nu...

Digital Material Representation (DMR) concept in application to numerical investigation of the two different types of epoxy/glass composite morphologies under loading conditions is addressed within the paper. First, two algorithms for reconstruction of digital microstructures based on metallography investigations are developed. Then, material prope...

Modelling of metal forming processes is an essential task of production engineering. Due to the latest technological developments, a huge variety of models is already available and extending continuously. Thus, it is important to find a suitable model. This paper gives an overview on the common classification and characterization of modelling and m...

The strain-induced precipitation process of Nb(C,N) is widely used in microalloyed steels to improve the strength and ductile-to-brittle transition temperature. During thermomechanical processing of these steels, disperse second-phase particles precipitate and effectively stop the static recrystallization progress. As an effect, unrecrystallized au...

The Ti–6Al–4V alloy wires were plastically deformed using the accumulative angular drawing (AAD) process at room temperature with a maximal logarithmic strain ε ~ 0.51. Microstructure and microtexture evolution and inhomogeneity of the Ti alloy wires were investigated quantitatively using the electron backscattered diffraction technique within the...

Major, recent developmental trends in the field of metal forming are presented in the paper both from experimental and numerical point of view. First, progress made in metal forming processes such as: rolling of long flat products, cross wedge rolling, open die forging, die forging, extrusion, drawing, and stamping are addressed. Then, the study pr...

The paper presents the first experimental verification of dislocation repulsion during springback of Dual Phase (DP) steel, a mechanism which is suggested to cause non-linear unloading due to micro-plastic strain generation. In-situ loading-unloading tests are conducted within a Scanning Electron Microscope (SEM). It is shown that strain partitioni...

The approach to evaluate possibilities offered by the digital material representation (DMR) concept in application to numerical investigation of deformation inhomogeneities in pulsed laser deposited (PLD) thin films is presented within the work. Concepts of the DMR model as well as developed algorithms for statistical representation of typical morp...

The work is focused on the concept of identification of critical parameters of the random cellular automata finite element (RCAFE) fracture model. The investigated parameters are related to the fracture initiation criteria at the micro scale level for further simulation of the dual phase steel behaviour under deformation conditions. Parameters for...

The behaviour of porous sinters, during compression and compression with reverse cyclic torsion tests is investigated in the article based on the combination of experimental and numerical techniques. The sinters manufactured from the Distaloy AB powder are examined. First, series of simple uniaxial compression tests were performed on samples with t...

The high temperature deformation behavior of a new magnesium alloy, ZE20 (Mg-2.4%Zn-0.2%Ce), using uniaxial isothermal compression testing, is investigated within the paper. A set of experiments was conducted at temperatures of 350–425 °C, and strain rates in the range of 0.01 s⁻¹ to 10 s⁻¹, and samples were compressed by 70% of their original leng...

A through scale investigation of a porosity shape and morphology after sintering of the Distalloy AB powder is the goal of the paper. First, the classical two dimensional analysis of porosity geometrical aspects is presented with the use of the systematic scanning technique (SST) and the light microscopy (LM). Then, a three dimensional investigatio...

Development and application of the hybrid fully coupled, random cellular automata finite element (RCAFE) approach to modelling dynamic recrystallization phenomenon, during a high temperature deformation is the overall goal of the paper. The finite element (FE) solver provides information on equivalent stress, equivalent strain, temperature fields a...

A parallel implementation of the cellular automata static recrystallization model is the subject of the present paper. First, a description of theoretical assumptions of the static recrystallization model including nucleation and grain growth stages is summarized. After that crucial modifications that have been introduced to the model to handle par...

Development of the 2D concurrent multiscale numerical model of novel incremental forming (IF) process is the main aim of the paper. The IF process is used to obtain light and durable integral parts, especially useful in aerospace or automotive industries. Particular attention in the present work is put on numerical investigation of material behavio...

The overall goal of the research, is development of the numerical model capable of replicating local heterogenous material behavior of thin film materials under loading conditions. This particular work is focused on determination of flow stress characteristics of investigated TiN thin film based on the nanoindentation test. To properly recalculate...

Recent progress in application of digital/virtual microstructure models in the area of metals engineering science is presented within the paper. First, various approaches to digital reconstruction of microstructure morphology of investigated materials is presented. Possibilities of generation of both: exact replicas of morphology, as well as, synth...

Perceptive review of progress in development of ferrous materials models for computational engineering applications is the subject of the present work. Development of both micro/macro mean field and full field material models during last forty years is presented and discussed. Evolution of conventional mean field models based on closed form or diff...

Development of the Digital Material Representation (DMR) model, based on 3D reconstruction algorithm and serial sectioning, is the main goal of the present paper. Details on the serial sectioning and image processing algorithms are presented first. Serial sectioning is realized on the basis of light microscopy (LM). Then concept of 3D reconstructio...

Recently developed accumulative angular drawing (AAD) combined with wire drawing (WD) and wire flattening (WF) processes were employed to effectively induce severe plastic deformation (SPD) effects into drawn wires. The influence of combined effects of area reduction, bending, shearing, and burnishing on the accumulated deformation energy and micro...

Development of finite element (FEM)/eXtended finite element (XFEM) numerical solution combined with the digital material representation (DMR) approach to simulate brittle/ductile fracture is the subject of the present work. The paper is divided into three main parts. In the first, proposed procedures for development of DMR model of investigated two...

Multi-scale computer aided design of manufacturing processes of a magnesium bracket for the automotive industry is the main goal of the present paper. Tensile tests at various deformation conditions (temperatures, strain rates etc.) were performed to obtain flow stress data necessary for the macro-scale finite element analysis. The digital material...

Dual-phase (DP) steel sheets are subjected to large plastic strains during forming of the body and structures of automotive components. These steels primarily contain hard martensite and soft ferrite phases in their microstructure and involve brittle and ductile fracture mechanisms for the ferrite and martensite phases, respectively. An uncoupled,...

The development of extrusion technology for a new magnesium alloy ZE20 (2.4 %wt. Zn, 0.2 %wt. Ce) requires evaluation of a model for the alloy’s deformation behavior. In this study, compression tests have been carried out for a wide range of temperatures (350-425 °C) and strain rates (0.01-10.0 s⁻¹) corresponding to a wide range of extrusion parame...

The overall goal of the research, is development of the numerical model capable of replicating local heterogenous material behavior of thin film materials under loading conditions. This particular work is focused on determination of flow stress characteristics of investigated TiN thin film based on the nanoindentation test. To properly recalculate...

Development of two approaches for creation of digital microstructure representations of sintered porous metals for further numerical simulations is the goal of the paper. Initially, an approach based on series of exact replicas of real 2D microstructures processed by image analysis and reconstruction algorithms was proposed. Thus, developed in-hous...

Development of the innovative approach to micro scale cellular automata (CA) space deformation during dynamic recrystallization process (DRX) is the main goal of the present paper. Major assumptions of the developed CA DRX model as well as novel space deformation algorithm, which is based on the random cellular automata concept and FE method, are d...

Development of a discrete/continuum numerical model of different failure modes operating in dual phase steels during deformation is the main goal of the research. Proposed approach is based on a random cellular automata (RCA) model incorporated in a fully coupled manner to the finite element (FE) framework. As a result, the RCAFE model that can tak...

Review of dynamic recrystallization models is the subject of the present work. Development of both mean field and full field approaches during last three decades is presented and discussed. Conventional mean field models based on closed form equations as well as differential equations are presented first. Then full field models are elaborated focus...

The potential of discrete cellular automata technique to predict the grain refinement in wires produced using combined metal forming process is presented and discussed within the paper. The developed combined metal forming process can be treated as one of the Severe Plastic Deformation (SPD) techniques that consists of three different modes of defo...

Development of fast and efficient finite element model for rolling industrial grades of two DP steels was the subject of the present paper. Basis of the finite element framework, as well as material model development stages, are presented first. Model validation with experimental measurements is shown next. Finally, selected examples of multi scale...

The main goal of this work is development of the incremental-forming (IF) process for manufacturing integral elements applicable to the aerospace industry. A description of the proposed incremental-forming concept based on division of large die into a series of small anvils pressed into the material by a moving roll is presented within this article...

Critical evaluation of influence of time step length and cell size on cellular automata models behavior during microstructure evolution simulations is the subject of the present work. Dynamic Recrystallization was selected as a case study for CA model application. First, general information on CA model assumptions are presented. Then series of adva...

Validation and further application of a coupled cellular automata – finite element model to investigate the influence of the degree of deformation on static recrystallization kinetics (SRX) during annealing of low carbon steels after cold rolling is presented within the work. Descriptions of major model components involving digital material represe...

Development of the multiscale numerical model of innovative incremental forming process, dedicated for manufacturing complex components for the aerospace industry is the main aim of the work. Description of the incremental forming concept based on division of large die into a series of small anvils subsequently pressed into the material is presente...

In the present work Digital Material Representation (DMR) approach was utilized to simulate the deformation behavior of the two phase Ti-6Al-4V alloy. DMR models of the two phase structure, containing different morphologies of alpha grains within a beta matrix – lamellar and equiaxed, were created. Each phase was then separated and different mechan...

The main goal of the paper is dedicated to proper arrangement of the Finite Element (FE) and Random Cellular Automata (RCA) methods in order to develop numerical model of dynamic recrystallization (DRX) and therefore to simulate microstructure morphology changes during plastic deformation at elevated temperatures. In the approach, Finite Element so...

The phase transformation model incorporated via the user subroutines to the commercial finite element software to accurately predict changes occurring during cooling of metallic components is presented in the paper. The cooling process of steel rings used in airplanes was selected as a case study. Particular attention was put on heterogeneities occ...