New surface reinforcement using a combination of crack-healing and electron beam irradiation is proposed for structural ceramics. The influence of electron beam irradiation on the surface hardness was investigated in the present study. Hot-pressed alumina-30 vol. percent SiC particles composite was crack-healed, via a high-temperature oxidation treatment in air at 1573 K for 1 h. Then, the specimens passed through an electron beam curtain to homogeneously irradiate (he crack-healed specimens. The total dose of irradiation was controlled by repeating the procedure. Depth profiles of hardness were measured using Vickers indentation with several indented loads. The hardness of the electron beam irradiated specimens increased from that of crack-healed specimens without electron beam irradiation in the vicinity of the surface. The depth influenced by electron beam irradiation was found to be about 2 mu m. Irradiation of 0.432 MGy caused a 38 percent hardness increment to surface of the crack-healed specimens. A similar irradiation effect was achieved in non crack-healed specimen. The hardness in the vicinity of the surface varied with electron beam irradiation dose and the optimized conditions of electron beam irradiation to crack-healed and non crack-healed specimens were determined to be 0.432 MGy and 0.216 MGy, respectively.
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