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  - Artzt, Katia
A1  - Haubrich, Jan
A1  - Requena, Guillermo
A1  - Bruno, Giovanni
T1  - New aspects about the search for the most relevant parameters optimizing SLM materials
JF  - Additive manufacturing
N2  - While the volumetric energy density is commonly used to qualify a process parameter set, and to quantify its influence on the microstructure and performance of additively manufactured (AM) materials and components, it has been already shown that this description is by no means exhaustive. In this work, new aspects of the optimization of the selective laser melting process are investigated for AM Ti-6Al-4V. We focus on the amount of near-surface residual stress (RS), often blamed for the failure of components, and on the porosity characteristics (amount and spatial distribution). First, using synchrotron x-ray diffraction we show that higher RS in the subsurface region is generated if a lower energy density is used. Second, we show that laser de-focusing and sample positioning inside the build chamber also play an eminent role, and we quantify this influence. In parallel, using X-ray Computed Tomography, we observe that porosity is mainly concentrated in the contour region, except in the case where the laser speed is small. The low values of porosity (less than 1%) do not influence RS.
KW  - SLM
KW  - Ti-6Al-4V
KW  - X-ray synchrotron diffraction
KW  - Computed tomography
KW  - Residual stress
Y1  - 2018
U6  - https://doi.org/10.1016/j.addma.2018.11.023
SN  - 2214-8604
SN  - 2214-7810
VL  - 25
SP  - 325
EP  - 334
PB  - Elsevier
CY  - Amsterdam
ER  -