Increase of Si solution rate into Al matrix by repeated irradiation of intense pulsed ion beam

An ion beam treatment of a high-silicon aluminum alloy (Al-30Si) is performed by the irradiation of a proton intense pulsed ion beam (IPIB) which has the ion energy of 180keV, the ion current density of 460A/cm(2), and the pulse duration of 65ns. The EPMA analysis shows the dispersion of small eutectic silicon crystals and the erosion of the boundary of large primary silicon crystals by repeated IPIB-irradiation. The solution rate of silicon in aluminum that was calculated from the variation of X-ray diffraction angle of aluminum was about 5.7% after 50 shots IPIB-irradiation, which exceeds the solid solubility limit (1.59%) of silicon in aluminum. The thickness of the treated layer was found to be 7 mum, and the hardness of treated layer was H-v = 120 corresponding to twice of the untreated one. (C) 2002 Elsevier Science Ltd. All rights reserved.