Revealing the Effect of Local Connectivity of Rigid Phases during Deformation at High Temperature of Cast AlSi12Cu4Ni(2,3)Mg Alloys

K. Bugelnig , H. Germann , T. Steffens , F. Sket (1) , J. Adrien (2) , E. Maire (2) , E. Boller (3) , G. Requena (4)

1 Institute IMDEA Materials [Madrid]
2 MATEIS - Matériaux, ingénierie et science [Villeurbanne]
3 ESRF - European Synchrotron Radiation Facility
4 DLR Institut für Werkstoff-Forschung / Institute of Materials Research

The 3D microstructure and its effect on damage formation and accumulation during tensile deformation at 300 degrees C for cast, near eutectic AlSi12Cu4Ni2Mg and AlSi12Cu4Ni3Mg alloys has been investigated using in-situ synchrotron micro-tomography, complemented by conventional 2D characterization methods. An increase of Ni from 2 to 3 wt.% leads to a higher local connectivity, quantified by the Euler number x, at constant global interconnectivity of rigid 3D networks formed by primary and eutectic Si and intermetallics owing to the formation of the plate-like Al-Ni-Cu-rich delta-phase. Damage initiates as micro-cracks through primary Si particles agglomerated in clusters and as voids at matrix/rigid phase interfaces. Coalescence of voids leads to final fracture with the main crack propagating along damaged rigid particles as well as through the matrix. The lower local connectivity of the rigid 3D network in the alloy with 2 wt.% Ni permits localized plastification of the matrix and helps accommodating more damage resulting in an increase of ductility with respect to AlSi12Cu4Ni3Mg. A simple load partition approach that considers the evolution of local connectivity of rigid networks as a function of strain is proposed based on in-situ experimental data.

Keywords: Aluminum alloys; Cracks; Deformation; Eutectics; Indium alloys; Magnesium alloys; Matrix algebra; Metallographic microstructure; Nickel; Phase interfaces; Tomography; 3D characterization; 3D microstructures; Cast Al-Si alloys; Connectivity; Damage; In-situ tensile; Strength; Synchrotron tomography; Silicon alloys; AL-SI ALLOYS; MECHANICAL-PROPERTIES; PISTON ALLOY; TENSILE DEFORMATION; ALSI12CUMGNI ALLOY; MG ALLOYS; STRENGTH; CU; MICROSTRUCTURE; FATIGUE

Domains: Life Sciences [q-bio]

K. Bugelnig, H. Germann, T. Steffens, F. Sket, J. Adrien, et al.. Revealing the Effect of Local Connectivity of Rigid Phases during Deformation at High Temperature of Cast AlSi12Cu4Ni(2,3)Mg Alloys. Materials, 2018, 11 (8), pp.1300-1-1300-18. ⟨10.3390/ma11081300⟩. ⟨hal-01916329⟩