The role of intermetallics in stress partitioning and damage evolution of AlSi12CuMgNi alloy

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 736; pp. 453 - 464
• Main Authors: Evsevleev, S., Mishurova, T., Cabeza, S., Koos, R., Sevostianov, I., Garcés, G., Requena, G., Fernández, R., Bruno, G.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 24.10.2018; Elsevier BV
• Subjects: Alloy development; Alloying elements; Aluminum; Aluminum alloys; Axial stress; Compression tests; Computed tomography; Damage; Damage assessment; Diffraction; Intermetallic compounds; Internal stress; Metallurgical constituents; Micromechanical modeling; Neutron diffraction; Neutrons; Partitioning; Phases; Pressure casting; Settlements & damages; Silicon; Tomography; Aluminum alloys; Internal stress; Computed tomography; Damage; Neutron diffraction; Micromechanical modeling
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2018.08.070

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.