Mechanical properties of intermetallic inclusions in Al 7075 alloys by micropillar compression

• Inclusions in Al alloys can be classified as Fe and Si-bearing intermetallics.
• Mechanical properties of inclusions were studied using micropillar compression.
• Stress–strain behavior of these intermetallics was obtained experimentally.
• Compressive failure and yield strength were determined.

The constituent particles (also called inclusions) play an important role in the deformation behavior of Al 7075 alloys. The majority of inclusions in Al 7075 alloys can be classified as Fe-bearing and Si-bearing inclusions. Among them Al7Cu2Fe and Mg2Si are predominant. In this study, the mechanical properties of these inclusions and Al 7075 matrix were studied using micropillar compression testing. Micropillars were fabricated by focused ion beam (FIB) milling and were tested using a nanoindenter equipped with a flat tip. For the first time, the stress–strain behavior of these intermetallic particles was obtained experimentally, resulting in the measurement of the compressive failure and yield strength. The stress–strain behavior obtained from pillar compression show that both inclusions possess higher strength than the Al 7075 matrix.