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Indexed by:Journal Papers

Date of Publication:2020-02-25

Journal:SURFACE & COATINGS TECHNOLOGY

Included Journals:EI、SCIE、CPCI-S

Volume:384

ISSN No.:0257-8972

Key Words:High intensity pulsed ion beam (HIPIB); Mechanical properties; Microstructure; Crystalline molybdenum

Abstract:In this paper, high intensity pulsed ion beam (HIPIB) of 85% Cn+ + 15% H+ was used to irradiate crystalline molybdenum. Before and after irradiation, the surface structure and mechanical properties were studied with different irradiation times and energy densities. After HIPIB irradiation, stress was generated inside the molybdenum. As the energy density increases, the thermal effect which was enhanced apparently causes a preferred orientation in the molybdenum. When the energy density reaches 1.6-2.5 J/cm(2) with 3 pulses, craters and cracks appear on the surface of molybdenum. Besides, the alpha-Mo2C phase formed in the near-surficial region of molybdenum is beneficial to the hardness increasement. After HIPIB irradiation, the ratio of average hardness (H-irr/H-unirr) and Nix-Gao model show that the macro hardness of molybdenum decreases with the increase of pulse number and energy density. Compared with the effect of ion implantation on hardness improvement, the annealing effect of HIPIB thermal irradiation plays a more important role in the reduction of molybdenum hardness. The hardness of the molybdenum decreases under the combined action.