Abstract In an earlier work (Tang et al., 2020), we derived evolution equations governing dynamic void growth in amorphous materials with a number of idealizing assumptions. Here, we extend and further generalize the constitutive theory to better account for general stress states, strain-softening, stable and unstable void growth modes, as well as viscous and micro-inertial retarding effects on void

Abstract The Mullins-type damage behaviors in double network hydrogels have attracted a broad research interest in recent years. However, most of current works focus on characterizing and modeling the uniaxial deformation behaviors of these materials. In this work, we combine experimental and theoretical approaches to investigate the anisotropic damage behaviors of double network hydrogels revealed

Abstract The plastic deformation behavior under various strain-path changes in an A6022-T4 Al alloy sheet was studied, focusing on the evolution of the direction of the plastic strain rate θ and the stress ratio φ after abrupt strain-path changes. A cruciform specimen was used to measure the evolution of the plastic deformation behavior after abrupt strain-path change experimentally. Before the strain-path

Abstract The present work addressed the effects of heat treatment on the mechanical response of a WE43 Mg alloy using an integrated framework of SEM-DIC experiment and CPFE simulation. Both macroscopic responses including yield strength, ultimate strength, ductility, and microscopic responses, including local displacement and strain maps, were experimentally investigated. The focus of this work is

Abstract Nano-dual-phase glass-crystal (NDPGC) metallic materials as the novel nanostructured materials have been proved experimentally to possess excellent mechanical properties, e.g. the nearly ideal strength. The present work is concerned with the constitutive analysis of size-dependent deformation behaviors in micropillars of a NDPGC alloy based on the micromechanics approach. The mechanism-based

Abstract Accurately representing the process of porosity-based ductile damage in polycrystalline metallic materials via computational simulations remains a significant challenge. The heterogeneity of deformation in this class of materials due to the anisotropy of deformation of individual single crystals creates the conditions for the formation of a damage field. In this work, a technique of soft-coupled

Abstract The applications of Al alloys are often limited by their low mechanical strength. Methods such as grain refinement and amorphization usually raise mechanical strength but sacrifice plasticity. Strength and plasticity are largely dictated by dislocation-defect interactions in crystalline materials and by shear banding in metallic glasses, depending significantly on the length scales of microstructural

Abstract. In this study, a physics-based model is proposed to predict the γ/γ´ microstructure evolution of single crystal (SC) superalloy at medium temperature and high stress level. Considering multiple hardening mechanisms, the crystal plasticity (CP) model accounting for γ/γ´ microstructure evolution is developed to predict the creep strain. Creep fracture and interrupted tests are conducted for

Abstract The creep behaviour of directionally solidified SAC305 (96.5Sn-3Ag-0.5Cu wt%) alloy has been investigated with integrated particle matrix composite (PMC) crystal plasticity modelling and quantitative experimental characterisation and test. In this manuscript, the mechanistic basis of creep rate dependence is shown to be influenced by plastic strain gradients, and the associated hardening due

The purpose of continuum plasticity models is to efficiently predict the behavior of structures beyond their elastic limits. The purpose of multiscale materials science models, among them crystal plasticity models, is to understand the material behavior and design the material for a given target. The current successful continuum hyperelastoplastic models are based in the multiplicative decomposition

Abstract Machine learning (ML) approaches are widely used to develop systems or frameworks with the ability to predict the properties of interest by learning and establishing relationships and inferences from data. In the present work, an ML based framework is proposed to predict the evolution of local strain distribution, plastic anisotropy and failure during tensile deformation of AlSi10Mg aluminum

Abstract Hydro-mechanical coupling is a crucial element in constitutive modelling of partially saturated soils, given the dependence of the macro behaviour on the interaction between frictional sliding, grain rearrangement and ruptures of liquid bridges and their redistributions at the grain contacts. The inseparable nature of this interaction requires the interdependence of all internal variables

Abstract Carbon nanotube (CNT) fibers are inevitably subject to severe plastic deformation under complex loading conditions while applying in wearable electronics. In this work, we uncover the time-dependent structure evolution mechanism of twisted CNT fibers by a series of continuous and discontinuous loading experiments. The results reveal that the highly twisted CNT fibers are more sensitive to

Abstract This work focuses on the experimental investigation into the heat-treatment influence on the plastic flow behavior of the laser metal deposited (LMD) Nickel-base superalloy Inconel 718 and the microstructural based constitutive modeling. The uniaxial compressive mechanical response of the LMD Inconel 718 superalloy was tested over wide ranges of temperature (298–1273 K) and strain rate (500

Abstract Micro-spalling is a dynamic fragmentation process that is coupled with shock-induced overheating and melting. It has been observed in series of shock experiments and in several modern industrial applications such as inertial confinement fusion and laser-shock surface micromachining. Modeling micro-spalling is beyond the scope of traditional damage mechanics which ignores solid–liquid transformation

Abstract The impact of the Portevin-Le Chatelier (PLC) effect on plasticity and fracture ahead of a severe notch is investigated by DIC field measurements for C-Mn steel. The PLC effect causes an intermittent activity of highly localized strain rate bands. This first high temperature investigation of the effect of a notch on the PLC localization bands is successfully reproduced numerically in terms

Abstract A strain gradient crystal plasticity finite element model is developed to study the evolution of internal and localized elastic strains in hexagonal close-packed polycrystals. The results of the model are firstly compared to the previously published data for a series of in-situ neutron diffraction experiments conducted on α-zirconium specimens. The development of internal lattice strains is

Abstract Porous plasticity aims to model the growth and coalescence of voids leading to ductile failure. The GTN model (1984), resulting from heuristic modifications to Gurson's homogenized hollow sphere model (1977), is used in numerous publications. The Rousselier model (1981), developed in the framework of continuum thermodynamics, is apparently similar. Both models are effective in numerical calculations

Abstract The acoustic softening effect in metals during plastic deformation has been widely investigated in the past decades. However, the mechanism of such an acoustic plasticity remains controversial. As a result, several models were proposed to understand the acoustic softening effect in terms of stress superposition, thermal activation theory, crystal plastic theory and other mechanisms associated

Abstract The asymmetric mechanical response and corresponding statistical grain-scale slip/twinning activity for extruded Mg-(0~5 wt%)Y sheets during room-temperature uniaxial tension and compression along the extruded direction were investigated using slip trace analysis and EBSD-based misorientation analysis. The tension-compression asymmetry, in terms of yield strength, ultimate strength and uniform

Abstract A fourth order polynomial yield criterion (Poly4) and a non-quadratic yield function are coupled under associated flow rule to describe the evolution of anisotropic yielding behavior analytically. The Poly4 part takes a great role in describing the evolution of these anisotropic behaviors throughout deformation history. The non-quadratic part is isotropic under uniaxial tension loading, which

Abstract Upon employing the conservation theorem and continuum theory, the configurational force on a singularity, or a defect, is given by a path-independent integral called the J integral. According to the continuum elasticity theory, the J integral around a steadily moving dislocation is equal to the Peach–Koehler force acting on the dislocation and is independent of the integration path. However

Abstract The plastic deformation behavior of single crystals of the δ1p and δ1k phase compounds in the Fe–Zn system, which are the major constituent phases in the coating layer of galvannealed (GA) steels, has been investigated by micropillar compression tests at room temperature as a function of crystal orientation and specimen size. (0001)[11 2 ‾ 0] basal slip and (10 1 ‾ 0)[ 1 ‾ 2 1 ‾ 0] prism slip

Abstract This paper formulates stress-assisted and strain-induced austenite to martensite transformation kinetics laws within a crystal plasticity framework to enable modeling of strain path sensitive elasto-plastic deformation of austenitic steels taking into account the evolution of crystallographic texture and the directionality of deformation mechanisms in the constituent phases. Consistent with

Abstract The plastic flow characteristics of body centered cubic metals, which is dominated by the motion of screw dislocations, generally exhibits strong strain rate dependence. In-situ scanning electron microscopy compression tests are performed on tungsten (W) single crystal nano and micro pillars, with diameters in the range 100-2000 nm. We demonstrate here that by reducing sample size, the strain

Abstract Tensile and creep responses of Cu-Nb composites are predicted at 400 ° C using a high-temperature discrete dislocation plasticity (DDP) framework where the multilayer composites are idealized as two-dimensional unit cells with periodic boundary conditions. Considering the fact that the interfaces in multilayer composites dominate their plastic response, bi-material interfaces are treated here

Abstract Predicting history-dependent materials’ responses is crucial, as path-dependent behavior appears while characterizing or geometrically designing many materials (e.g., metallic and polymeric cellular materials), and it takes place in manufacturing and processing of many materials (e.g., metal solidification). Such phenomena can be computationally intensive and challenging when numerical schemes

Abstract Crystal plasticity (CP) models have been evolving since their inception. Advanced experimental characterization methods have contributed significantly to assess the performance and subsequent improvement of many empirical relations in CP, which were directly adopted from classical plasticity theories of solids at the macro-scale. In this research, high energy X-ray diffraction microscopy (HEDM)

Abstract The plastic deformation at high temperatures of two-phase titanium alloys is modelled using a mesoscale approach to describe the complex interactions between different populations of dislocation densities. The static and dynamic recovery, as well as of continuous dynamic recrystallization, is modelled. The flow stresses of both α and β phases are calculated using constitutive equations combined

Abstract A dual-scale finite element model is proposed to investigate the failure of ferrite-bainite (FB) dual-phase steel in the hole expansion test. The first level simulation solves the elastic-plastic deformation behavior with phenomenological isotropic elastic-anisotropic plastic constitutive models, and its resulting local deformation histories are supplied to the second level simulation as boundary

Abstract With elevated confining pressure and low temperatures, geomaterials may exhibit brittle-to-ductile failure transition due to increased cataclastic flow. In this work, we propose a modified phase-field damage model to capture this transition, wherein a portion χ f of the plastic work that contributes to the fracture driving force, is assumed. In particular, we propose to compute χ f based on

Abstract Grain boundary mechanics plays a key role in the strengthening of polycrystals. In this study, deformation of aluminum grains is investigated to better understand the origins of strengthening mechanisms near the grain boundaries. For this reason a sample with nearly columnar structure was prepared and fully characterized by electron back scattered diffraction measurements using the two side

Abstract Dislocation climb is an important high temperature process of metals plasticity, responsible for the phenomena such as creep, swelling, or hardening. Climb is defined by the ability of dislocations to leave their original glide plane by interaction with point defects. As such, dislocation climb is controlled by point defect diffusion/absorption/emission, which all involve thermal activation

Abstract Thermoplastic polymers (TP) are well-suited for thermoforming and injection moulding processes. Semi-crystalline polymers (SCP) are a specific class of TPs, which partly crystallize after cooling from the melt. During thermoforming processes, SCPs are subjected to large deformations and thermal loadings and show strong thermo-mechanical coupling effects. In addition, the evolution of the crystalline

Abstract Extension twin nucleation and variant selection in magnesium alloy WE43 is investigated in experimentally characterised and deformed microstructures replicated in crystal plasticity models. Total stored (dislocation) energy density is found to identify the experimentally observed locations of twins which are not otherwise explained by global Schmid factors or local resolved shear stress criteria

Abstract A machine learning based model is proposed to describe the temperature and strain rate dependent response of polypropylene. A hybrid modeling approach is taken by combining mechanism-based and data-based modeling. The “big data” required for machine learning is generated using a custom-made robot-assisted testing system. Numerous large deformation experiments are performed on mildly-notched

Abstract The mobility of edge dislocation in Cu–Ni solid solution alloys within a wide range of temperatures 100–1100 K and Ni concentrations 0–30 at.% is studied by molecular dynamics simulation. Two different regimes of the influence of substitutional Ni atoms on the motion of edge dislocation are observed. In the first regime, in which the velocity of edge dislocation is much less than the shear

Abstract A non-associated flow rule (non-AFR) constitutive model is proposed to describe the evolving yield stress and plastic potential surfaces of sheet metal under plane stress conditions. The yield stress function is a multiplication of two yield functions, within the first part includes an asymmetric pressure-sensitivity that considers anisotropic and asymmetric yielding of sheet metals. This

Abstract Complex structural components made from 7xxx series alloys are usually manufactured through hot stamping due to their low ductility at room temperature. With the help of a custom-made induction heating system, experiments are performed on aluminum alloy 7075 in its W-temper. The comprehensive experimental program is executed comprising more than 100 specimens to characterize the plasticity

Abstract A novel elasto-visco-plastic self-consistent (EVPSC) formulation based on the scheme of the homogeneous effective medium is presented. The constitutive behavior of a polycrystal is described as that of an elasto-visco-plastic effective medium interacting with grains treated as elasto-visco-plastic ellipsoidal inclusions. The formulation is based on the definition of a unique elasto-visco-plastic

Abstract In this paper, the analysis of the low cycle fatigue behavior of P91 steel is presented. First, experimental tests are performed to recognize different aspects of material behavior. Then an appropriate constitutive model is developed within the framework of thermodynamics of irreversible processes with internal state variables. Two different approaches to fatigue damage modeling are applied

Abstract Magnesium alloy sheets usually has to be processed by warm forming, and change of strain path and evolution of microstructure can significantly influence their warm formability. Forming limit test for an AZ31B alloy sheet under strain path changes was configured and implemented, and the effects of strain paths and microstructure evolution on the forming limit diagram are investigated. The

Abstract The deformation behavior of solid polymers under isothermal, quasi-static loadings is investigated. A comprehensive test program consisting of tension, torsion, and combinations thereof was conducted on a polycarbonate polymer under both monotonic and long-term cyclic loadings. The effects of different loading modes, creep load conditions, mean stress, stress amplitude, and loading rate are

Abstract In this study we present an integrated experimental and computational study of the effect of twin crystallographic orientation on local deformation characteristics that govern its subsequent growth. Experimentally measured intra-twin geometrically necessary dislocations (GND) density and twin-resolved shear stress (TRSS) differences within twins are found to vary with twin crystallographic

Abstract The structure of steady shock waves in porous solids is a complex phenomenon involving in general the interplay of micro-inertia effects with the nonlinear elastic viscoplastic matrix response. Micro-inertia effects are due to the important acceleration of material particles in the vicinity of collapsing voids. By adopting the analytical approach recently developed for porous metals by Czarnota

Abstract Micro-scale thermal interface grooving (TIG), as an important breakdown mechanism of single lamella and the key to spheroidization of lamellar colony, does significant influence on the mechanical response and microstructural evolution of titanium alloy with lamellar colony during hot working. This influence may become remarkable by coupling with meso-scale deformation anisotropy of the colony

Abstract Using molecular dynamics simulations, we compute the mobility of an edge dislocation in a random FCC Fe0.70Ni0.11Cr0.19 alloy over temperatures from 100 to 900 K and shear stresses up to 600 MPa. Dislocation mobilities are shown to be intrinsically length-dependent when the line length is below a minimum value, with shorter lines having a reduced mobility. We show that this minimum line length

Abstract Predicting the dramatic changes in mechanical and physical properties caused by irradiation damage is key for the design of future nuclear fission and fusion reactors. Self-ion irradiation provides an attractive tool for mimicking the effects of neutron irradiation. However, the damaged layer of self-ion implanted samples is only a few microns thick, making it difficult to estimate macroscopic

Abstract Review of selected fundamental topics on the interaction between phase transformations, fracture, and other structural changes in inelastic materials is presented. It mostly focuses on the concepts developed in the author’s group over last three decades and numerous papers that affected us. It includes a general thermodynamic and kinetic theories with sharp interfaces and within phase field

Abstract It is well known that grain boundary sliding (GBS) provides stress concentration and initiates grain boundary fracture at the serrated grain boundary or grain triple junction during high-temperature creep. Recent reports on GBS occurring during deformation at room temperature suggest that stress concentration may occur due to GBS, which has a stress component parallel to the grain boundary

Abstract A phase-field model allowing to describe dislocation climb under irradiation is presented. Whereas previous phase-field models of the literature devoted to this phenomenon only take into account vacancies, our approach includes the effect of self interstitial atoms (SIAs) as required in the context of irradiated metals. Beyond the fact that it rigorously ensures the balance between the quantity

Abstract Modern aluminum industries need an in-depth understanding and a more accurate prediction of the flow stress and microstructure evolution during multi-stage thermomechanical processing. The underlying mechanisms of Al alloys are distinct from that of other metallic materials (e.g., steels and copper) owing to the very high stacking fault energy. In the hot forming process of ultra-high strength