Elasto-Plastic Deformation of Heterogeneous Metallic Materials: An Experimental Approach with AlMg4Si10

The increasing demand on thermo-mechanical strength, lightweight and formability in engineering applications require metallic materials with high sophisticated properties. Such functional alloys consist of heterogeneous composite-like microstructures, which are responsible for their stability in demanding service conditions (high temperature strength, low fatigue and creep resistance). External loads are distributed in between the phases of the alloys introducing high micro stress gradients, responsible for elastic and plastic deformation at the interfaces and micro crack initiation. Thus, the properties of such materials depend mainly on their phase shapes and 3D architectures leading to high stress gradients and elasto-plastic deformation under service conditions.This manuscript describes experimental studies on phase strain distribution for different heat treatment conditions in an AlMg4Si10 alloy. Neutron diffraction was used for strain measurement at an angle dispersive strain scanner with in-situ tensile test setup. Strain evolution under load and after unloading was measured to show elasto-plastic deformation behaviour in between the ductile α-Al matrix and stiff reinforcing Mg2Si and Si phases. The degree of plastification, its effect on micro stress gradients and its influence on crack initiation could be discussed and comparisons to other composite materials could be drawn.