The fracture toughness of Mg2Si determined by 3-point bending and the indentation microcracking method

The Mg2Si intermetallic compound was produced from the raw materials by melting in a vacuum furnace. The purity of the as-cast material was 98 vol.%. Continuous polishing of a surface containing microhardness indentation marks showed that the cracks initiated by the indenter were of the Palmqvist type. Equations developed by Niihara and Shetty et al. were applied on the data extracted from the microhardness indentations for calculating the fracture toughness of Mg2Si, and the average KIC values were found to be 0.80 and 0.62 MPa*m1/2, respectively. The KIC value found from Shetty�s equation is close to the experimental value of 0.64 MPa*m1/2 found by a three-point bending test.