Dec 8 – 10, 2020 Online only
Online event
Europe/Berlin timezone

Micromechanical response of multi-phase Al-alloy matrix composites under uniaxial compression

Dec 9, 2020, 2:30 PM
3h 30m
Online event

Online event

Speaker

Sergei Evsevleev

Description

Aluminum alloys are extensively used in the automotive industry. Particularly, squeeze casting production of Al-Si alloys is employed in the conception of metal matrix composites (MMC) for combustion engines. Such materials are of a high interest since they allow combining improved mechanical properties and reduced weight and hence improve efficiency. Being a multiphase material, most MMCs show complex micromechanical behavior under different load conditions. In this work we investigated the micromechanical behavior of two MMCs, both consisting of a near-eutectic cast AlSi12CuMgNi alloy, one reinforced with 15%vol. Al2O3 short fibers and the other with 7%vol. Al2O3 short fibers + 15%vol. SiC particles. Both MMCs have complex 3D microstructure consisting of four and five phases: Al-alloy matrix, eutectic Si, intermetallics, Al2O3 fibers and SiC particles.
The in-situ neutron diffraction compression experiments were carried out on the Stress-Spec beamline and disclosed the evolution of internal phase-specific stresses in both composites. In combination with the damage mechanism revealed by synchrotron X-ray computed tomography (SXCT) on plastically pre-strained samples, this allowed understanding the role of every composite’s phase in the stress partitioning mechanism. Finally, based on the Maxwell scheme, a micromechanical model was utilized. The model perfectly rationalizes the experimental data and is able to predict the evolution of principal stresses in each phase.

Primary authors

Sergei Evsevleev Tatiana Mishurova (BAM) Dr Gerardo Garcés (National Center for Metallurgical Research CENIM-CSIC, Madrid, Spain) Prof. Igor Sevostianov (Department of Mechanical and Aerospace Engineering, New Mexico State University, USA) Michael Hofmann Prof. Giovanni Bruno (BAM)

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