Strength of synthetic diamonds under tensile stresses produced by picosecond laser action

Results of an experimental-theoretical study of spallation in synthetic diamonds are presented. In this study, data were first obtained on dynamic tensile strength of poly- and singlecrystal diamond samples at mechanical loads of up to 0.34 TPa and strain rates of 10–100 µs−1. Shock-wave loading was performed by 70 ps laser pulses on a Kamerton-T facility using a Nd:glass laser (second harmonics λ = 527 nm, pulse energy of up to ≈3 J) at intensities of ≈8 TW/cm2. The obtained maximal value of the spall strength ≈16.4 GPa is 24% of the theoretical ultimate strength of diamond. Raman scattering experiments showed that a small amount of diamond was graphitized in the spall area on the backside of the sample.