TY - JOUR A1 - Bruno, Giovanni A1 - Fernández, R. A1 - González-Doncel, G. A1 - Garcés, G. T1 - Towards a comprehensive understanding of creep: Microstructural dependence of the pre-exponential term in Al JF - Materials Science & Engineering A N2 - We show that the equation proposed by Takeuchi and Argon to explain the creep behavior of Al–Mg solid solution can be used to describe also the creep behavior of pure aluminum. In this frame, it is possible to avoid the use of the classic pre-exponential fitting parameter in the power law equation to predict the minimum creep strain rate. The effect of the fractal arrangement of dislocations, developed at the mesoscale, must be considered to fully explain the experimental data. These ideas allow improving the recently introduced SSTC model, fully describing the primary and secondary creep regimes of aluminum alloys without the need for fitting. Creep data from commercially pure Al99.8% and Al–Mg alloys tested at different temperatures and stresses are used to validate the proposed ideas. KW - Creep KW - Aluminum alloys KW - Dislocations KW - Fractal KW - Stress exponent KW - Neutron diffraction PY - 2020 DO - https://doi.org/10.1016/j.msea.2020.139036 VL - 776 SP - 139036 AN - OPUS4-50437 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Evsevleev, Sergei A1 - Mishurova, Tatiana A1 - Cabeza, Sandra A1 - Koos, R. A1 - Sevostianov, I. A1 - Garces, G. A1 - Requena, G. A1 - Fernández, R. A1 - Bruno, Giovanni T1 - The role of intermetallics in stress partitioning and damage evolution of AlSi12CuMgNi alloy JF - Materials Science & Engineering A 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 - Computed tomography PY - 2018 DO - https://doi.org/10.1016/j.msea.2018.08.070 VL - 736 SP - 453 EP - 464 PB - Elsevier B.V. AN - OPUS4-45927 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -