Local modification of hardness in FeCu alloys by using swift heavy ion irradiation

Supersaturated Fe–1.2 wt.% Cu alloys were irradiated with 200 MeV Xe and 200 MeV Au ions at elevated temperatures. To make an irradiated region and an unirradiated region in specimens, a masking plate was put on the specimen during the irradiation. After the irradiation, the hardness was measured by using a conventional microhardness tester or a nano-indenter. We have found that the hardness only in irradiated region increases by the irradiation. The boundary of irradiated and unirradiated regions can be clearly identified by the difference in hardness. The present result implies that swift heavy ion irradiation can be used for the local modification of hardness in Fe–Cu supersaturated alloys.