Fracture behaviors and strength of Cu6Sn5 intermetallic compounds by indentation testing

In this study, the shear fracture behaviors of the Cu6Sn5 grains at the Sn-4Ag/Cu interface were studied by indentation test; the fracture mechanisms and shear strength were characterized through analyzing the indentation curves and fracture morphologies. Experimental results reveal that shear fractures of the Cu6Sn5 grains occur at the foundation or the center portion, depending on their size and shape, and there are bursts on the force-depth curves corresponding to the fracture. The shear fracture strength of the Cu6Sn5 grains fractured at their center portion is close to the shear strength of the Cu6Sn5 intermetallic compounds, and its average value is about 670 MPa. (C) 2011 American Institute of Physics. [doi:10.1063/1.3603032]