TY - JOUR A1 - Evsevleev, Sergei A1 - Mishurova, Tatiana A1 - Cabeza, Sandra A1 - Koos, R. A1 - Sevostianov, Igor A1 - Garcés, Gonzales A1 - Requena, Guillermo A1 - Fernandez, R. A1 - Bruno, Giovanni T1 - The role of intermetallics in stress partitioning and damage evolution of AlSil2CuMgNi alloy JF - Materials Science and Engineering: A-Structural materials: properties, microstructure and processing N2 - Load partitioning between phases in a cast AlSi12CuMgNi alloy was investigated by in-situ compression test during neutron diffraction experiments. Computed tomography (CT) was used to determine volume fractions of eutectic Si and intermetallic (IM) phases, and to assess internal damage after ex-situ compression tests. The CT reconstructed volumes showed the interconnectivity of IM phases, which build a 3D network together with eutectic Si. Large stresses were found in IMs, revealing their significant role as a reinforcement for the alloy. An existing micromechanical model based on Maxwell scheme was extended to the present case, assuming the alloy as a three-phase composite (Al matrix, eutectic Si, IM phases). The model agrees well with the experimental data. Moreover, it allows predicting the principal stresses in each phase, while experiments can only determine stress differences between the axial and radial sample directions. Finally, we showed that the addition of alloying elements not only allowed developing a 3D interconnected network, but also improved the strength of the Al matrix, and the ability of the alloy constituents to bear mechanical load. KW - Aluminum alloys KW - Neutron diffraction KW - Micromechanical modeling KW - Internal stress KW - Damage KW - Computed tomography Y1 - 2018 U6 - https://doi.org/10.1016/j.msea.2018.08.070 SN - 0921-5093 SN - 1873-4936 VL - 736 SP - 453 EP - 464 PB - Elsevier CY - Lausanne ER - TY - JOUR A1 - Mishurova, Tatiana A1 - Bruno, Giovanni A1 - Evsevleev, Sergei A1 - Sevostianov, Igor T1 - Determination of macroscopic stress from diffraction experiments BT - a critical discussion JF - Journal of applied physics N2 - The paper is motivated by some inconsistencies and contradictions present in the literature on the calculation of the so-called diffraction elastic constants. In an attempt at unifying the views that the two communities of Materials Science and Mechanics of Materials have on the subject, we revisit and define the terminology used in the field. We also clarify the limitations of the commonly used approaches and show that a unified methodology is also applicable to textured materials with a nearly arbitrary grain shape. We finally compare the predictions based on this methodology with experimental data obtained by in situ synchrotron radiation diffraction on additively manufactured Ti-6Al-4V alloy. We show that (a) the transverse isotropy of the material yields good agreement between the best-fit isotropy approximation (equivalent to the classic Kroner's model) and the experimental data and (b) the use of a general framework allows the calculation of all components of the tensor of diffraction elastic constants, which are not easily measurable by diffraction methods. This allows us to extend the current state-of-the-art with a predictive tool. Y1 - 2020 U6 - https://doi.org/10.1063/5.0009101 SN - 0021-8979 SN - 1089-7550 VL - 128 IS - 2 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Sevostianov, Igor A1 - Bruno, Giovanni T1 - Maxwell scheme for internal stresses in multiphase composites JF - Mechanics of Materials N2 - The paper focuses on the reformulation of classic Maxwell's (1873) homogenization method for calculation of the residual stresses in matrix composites. For this goal, we equate the far fields produced by a set of inhomogeneities subjected to known eigenstrains and by a fictitious domain with unknown eigenstrain. The effect of interaction between the inhomogeneities is reduced to the calculation of the additional field acting on an inhomogeneity due to the eigenstrains in its neighbors. An explicit formula for residual stresses is derived for the general case of a multiphase composite. The method is illustrated by several examples. The results are compared with available experimental data as well as with predictions provided by the non-interaction approximation (Eshelby solution). It is shown that accounting for interaction can explain many experimentally observed phenomena and is required for adequate quantitative analytical modeling of the residual stresses in matrix composites. KW - Residual stress KW - Multiphase composites KW - Interaction KW - Micromechanical schemes KW - Anisotropy Y1 - 2018 U6 - https://doi.org/10.1016/j.mechmat.2018.12.005 SN - 0167-6636 SN - 1872-7743 VL - 129 SP - 320 EP - 331 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Cabeza, Sandra A1 - Mishurova, Tatiana A1 - Garcés, Gonzales A1 - Sevostianov, Igor A1 - Requena, Guillermo A1 - Bruno, Giovanni T1 - Stress-induced damage evolution in cast AlSi12CuMgNi alloy with one- and two-ceramic reinforcements JF - Journal of materials science N2 - Two composites, consisting of an as-cast AlSi12CuMgNi alloy reinforced with 15 vol% Al2O3 short fibres and with 7 vol% Al2O3 short fibres + 15 vol% SiC particles, were studied. Synchrotron computed tomography disclosed distribution, orientation, and volume fraction of the different phases. In-situ compression tests during neutron diffraction in direction parallel to the fibres plane revealed the load partition between phases. Internal damage (fragmentation) of the Si phase and Al2O3 fibres was directly observed in CT reconstructions. Significant debonding between Al matrix and SiC particles was also found. Finally, based on the Maxwell scheme, a micromechanical model was utilized for the new composite with two-ceramic reinforcements; it rationalizes the experimental data and predicts the evolution of all internal stress components in each phase. Y1 - 2017 U6 - https://doi.org/10.1007/s10853-017-1182-7 SN - 0022-2461 SN - 1573-4803 VL - 52 SP - 10198 EP - 10216 PB - Springer CY - New York ER - TY - JOUR A1 - Bruno, Giovanni A1 - Kachanov, Mark A1 - Sevostianov, Igor A1 - Shyam, Amit T1 - Micromechanical modeling of non-linear stress-strain behavior of polycrystalline microcracked materials under tension JF - Acta materialia N2 - The stress-strain behavior of microcracked polycrystalline materials (such as ceramics or rocks) under conditions of tensile, displacement-controlled, loading is discussed. Micromechanical explanation and modeling of the basic features, such as non-linearity and hysteresis in stress-strain curves, is developed, with stable microcrack propagation and "roughness" of intergranular cracks playing critical roles. Experiments involving complex loading histories were done on large- and medium grain size beta-eucryptite ceramic. The model is shown to reproduce the basic features of the observed stress-strain curves. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. KW - Nonlinearity KW - Stress-strain relations KW - Hysteresis KW - Tension KW - Ceramics KW - Rocks KW - Polycrystals Y1 - 2018 U6 - https://doi.org/10.1016/j.actamat.2018.10.024 SN - 1359-6454 SN - 1873-2453 VL - 164 SP - 50 EP - 59 PB - Elsevier CY - Oxford ER -