The effect of mixed mode I/II on the fracture toughness and fracture behavior of nano-structured metal matrix composites

A nano-structured Al89Gd7Ni3Fe1 composite alloy was made from extruding its atomized amorphous powder at different extrusion ratios (ER). The effects of changing the notch radius from fatigue pre-crack to 100 μm on mode I fracture toughness were studied at different test temperatures (e.g., 298 K and 498 K). The effects of mixed mode (I/II) loading using different offset ratios were also studied at these temperatures. Increasing the test temperature showed a significant effect on the fracture toughness for mode I and mixed mode I/II conditions. Fracture surfaces were examined to reveal the nature of failure of such nano-structured Al composite materials at these loading conditions.