Microstructure and Strain Distribution Influence on Failure Properties in Eutectic AlNi, AlFe Alloys

Eutectic AlNi, AlFe, alloys exhibit plastic strains to failure (usually in the range of 1%- 5%), that those of structural alloys. We have developed a technique to measure strains at the scale of the microstructure and have used this method to assess the variation in failure properties with microstructure. This method is capable of using the grayscale information in the image of a gridded sample to obtain sub-pixel marker displacement, and can therefore accurately determine small strain values. Microstructures that exhibit large variation in local strain distribution tend to have higher variability in tensile properties, particularly tensile ductility, compared to microstructures that accumulate strain more uniformly. Orientation and morphology of lamellar plates in lamellar colonies play, also, a role in influencing the distribution of strain. Local grain orientation, phase distribution and segregation are factors influencing the strain distribution, and therefore the properties of these materials.