D.A. Davydov*, V.A. Gorokhov, A.V. Laushkin, A.V. Tselishev, Yu.G. Kostuk
National Scientific Center of Russian Federation "A.A. Bochvar All-Russian Scientific Research Institute of Inorganic Materials" (VNIINM), 123060 Moscow, P. Box 369, Russia, tel. (O95)-190-8085, FAX (095)-196-6671, E-mail: postmaster@vniinm402. msk.su; sav@bochvar.ru.
Plasma disruption loads onto different beryllium grades were simulated using GOS-1001 high power solid state laser. The impinging energy density was 0.5 MJ/m2 with pulse length of 3 microseconds.
Thermal shock crack formation and propagation response as well as erosion were studied. The dependence of damage initiation and evolution on the laser beam parameters such as pulse energy, number and length was studied for five beryllium grades. An average ablation depth was calculated using the size of the laser beam impact area and sample mass loss measurements. The measurements of the sample loss was performed using Sartorius microanalytical balance ensuring weighing accuracy of 5 micrograms.
The surface morphology was studied with a scanning electron microscope S-800. The studies have revealed that more intensive cracking takes place in coarse-grained structures. Fine-grained beryllium is relatively resistant to the thermal shock loads. A net of bulges is being formed on sample surface as result of melted beryllium crystallization. Structure of these bulges is porous.
Probable mechanisms of beryllium interaction with laser beam are discussed.