A confocal Raman microscopy technique is presented that allows stress measurement at the nanoscale, which in turn enables measurement of stress-intensity factors (SIF) at crack tips and thus toughness to be estimated. Peak-fitting and super-resolution techniques enable stress resolution of approximately 20 MPa at spatial resolution of approximately 100 nm. Micro- and nano-indentation and crack field stress distributions are measured and compared with analytical expressions. The SIF for indentation cracks in Si is shown to be in the range 0.2 MPa m1/2 to 0.4 MPa m1/2, consistent with chipping-induced indentation stress relief and the toughness of Si.
Proceedings Title: 12th International Conference on Fracture
Conference Dates: July 12-17, 2009
Conference Location: Ottawa, CA
Pub Type: Conferences