Impulsive fracture of fused quartz and silicon crystals by nonlinear surface acoustic waves

G. Lehmann, A. M. Lomonosov, P. Hess, P. Gumbsch
2003 Journal of Applied Physics  
During nonlinear evolution of laser-generated surface acoustic wave ͑SAW͒ pulses the stress increases with distance of propagation, and causes fracturing of brittle materials. This effect was used to evaluate the strength of isotropic fused quartz and anisotropic crystalline silicon with respect to impulsive loading in the nanosecond range and spontaneous cracking without using seed cracks. Crack nucleation and propagation along the surface was studied by optical microscopy and into the depth
more » ... nd into the depth of the bulk by the focused ion beam technique and confocal microscopy. In fused quartz, fracturing produced characteristic regular patterns at the surface with cracks extending into the bulk at an angle of 30°-35°to the surface in the direction of SAW propagation. On Si(111) surfaces cracks extended at the surface in the ͗110͘ direction and propagated along the weak ͕111͖ cleavage plane into the bulk. Other crack planes were observed in only a few cases, e.g., at a larger depth and on the Si(100) surfaces. The observed fracture behavior was rationalized by the complex displacement and stress tensor fields induced by elliptically polarized SAWs.
doi:10.1063/1.1594275 fatcat:ruxhsebonrhrpaqr2c534jk5f4