Indentation fracture toughness of amorphous steel

Indentation fracture toughness experiments were performed on amorphous steel. Measured toughness values were 3.2 +/- 0.3 MPa root m for 3-mm-thick specimens and 3.8 +/- 0.3 MPa root m for 10-mm-thick specimens. Crack geometry was determined be of the Palmqvist or radial configuration. High indentation loads >40 N were necessary for crack formation, and indentation cracks did not form adjacent to every indent, or in a uniform pattern. Possible reasons for crack formation thresholds and,geometry are discussed.