Fracture of metal carbides under ion irradiation at high temperature

Processes on titanium and niobium carbide surfaces under helium ion bombardment (20 keV) are investigated using secondary-ion energy-mass-spectrometry method. Interaction of residual oxygen with carbides results in oxycarbide formation. Oxycarbide decomposition is accompanied by oxygen, carbon, carbon and titanium oxides explosion-type ejection into vacuum for titanium carbide. Niobium oxycarbide decomposition starts at T ∼ 1350 deg C and is accompanied by niobium surface enrichment. Titanium oxycarbide decomposition takes place at T ∼ 1500 deg C. Recommendations, concerning carbide application to produce critical components of thermonuclear plant chambers, are presented