Desenvolvimento de ligas de AISI 316L endurecidas por dispersão de nano-óxidos de ítrio

Abstract

Austenitic steels are very important structure materials for fusion and fission nuclear reactors due to their excellent creep resistance at high temperature, and reasonable corrosion and oxidation resistance compared to ferritic steels. However, the ultimate tensile properties and stress corrosion resistance of austenitic steels are inferior at high temperature. The introduction of nano-sized oxide particles are expected to improve the strength and irradiation resistance of austenitic steels, because the oxide particles are very stable even at temperature close to the melting point of the steel and can be effective barriers to the motion of dislocations during tensile deformation. Therefore, the present work proposes a preparation of austenitic stainless steels with 0.35% wt. of Y2O3, Ti, Cu or all of them. They are characterized by X-ray diffraction, optical microscopy (OM) and scanning electron microscopy (SEM). The microhardness, gas permeation tests as well as thermal desorption spectroscopy (TDS) are conducted to evaluate the hardening mechanisms and hydrogen transport parameters. The alloys produced shows enhanced microhardness and hindered hydrogen transport. Therefore, nano-oxide dispersion is such a good strategy for producing advanced materials with superior mechanical and hydrogen-related properties.