S. A. Abrosimov

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.

Experimental investigation into polycrystalline and single-crystal diamonds under negative pressures formed by picosecond laser pulses

Results of the experimental investigation of the spallation phenomenon in polycrystalline and single-crystal synthetic diamond are presented. The shock-wave action on the target was formed by a laser pulse with a duration of 70 ps using a Kamerton-T installation. To attain the ablation pressure of 0.66 TPa on the face surface of the target, the laser radiation of the Nd:glass laser (second harmonics λ = 527 nm, the pulse energy is 2.5 J) was used at intensity up to 2 × 1013 W/cm2. The attained maximal spall strength of diamond σ* ∼ 16.5 GPa is 24% of the theoretical ultimate strength. The Raman scattering indicates that a small amount of crystalline diamond is graphitized in the spall region on the back target side.