Effects of Changes in Notch Radius and Test Temperature on the Toughness of a Nano-crystalline Aluminum Alloy Composite Produced via Extrusion of Amorphous Aluminum Alloy Powders

Amorphous aluminum alloy powders were extruded to produce a nano-crystalline aluminum alloy composite-containing nano-sized particles. Significant increases to the hardness/strength were obtained via the processing-induced evolution of 35 vol.% of nano-sized particles in the aluminum matrix. Acoustic measurements of the elastic constants revealed elastic modulus (E) in the range of 86-89 GPa. The fracture toughness of these nano-structured composite materials were evaluated at room temperature and 225 °C (498 K) on fatigue-precracked samples as well as on notched samples containing different root radii. The effects of changes in the root radius and test temperature on the toughness are compared to the behavior of conventional aluminum alloys and metal-matrix composites (MMCs).