Effect of carbon ion irradiation on the structural, mechanical and electrical properties of polycrystalline tungsten

Abstract

To investigate the effects of carbon ion irradiation on the structural, mechanical and electrical properties of polycrystalline tungsten, four tungsten specimens were irradiated by 5 MeV carbon ions (C+2) at various doses ranging from 0.5 ×1015 to 3 ×1015 ions cm-2 for different exposure times. X-ray diffraction analysis confirmed the slight structural modification by increase or decrease in diffracted peak intensity, crystallite size and lattice strains upon ion irradiation. In addition, there was no substantial evidence of new phase/s in α-tungsten at high energy ions. Initially, at a lower dose rate of 0.5 ×1015 ions cm-2, the average surface hardness and electrical resistivity were found to decrease due to the increase of crystallite size. However, elevated dosed (≥1 ×1015 ions cm-2) specimens show a significant increase in their surface hardness and electrical resistivity in comparison to un-irradiated ones. The variation of surface hardness and electrical resistivity of irradiated tungsten is well correlated with crystallographic modifications, which is ascribed to the generation, recombination, augmentation, and annihilation of ion-induced defects.