Effect of Gadolinium Addition on Microstructure, Mechanical Properties and Corrosion Resistance of 316L Austenitic Stainless Steels

Abstract 316L austenitic stainless steels containing 0.2–2.0 wt % gadolinium (Gd) were prepared through vacuum arc melting and subsequent hot rolling. Submicron and micron-sized Gd-rich phases precipitate along the grain boundaries and inside the grains in the as-cast samples. After hot rolling, the Gd-rich phases of an average size below 3 μm are homogeneously distributed when the Gd content is less than 1.5 wt %. When the Gd content increases to 2.0 wt %, some of the Gd-rich particles coarsen to about 6 μm and tend to aggregate. The hardness monotonously improves from 387 to 442 HV with increasing the Gd content from 0.2 to 2.0 wt % in the hot-rolled samples. The maximum yield strength and tensile strength, 635 and 741 MPa, respectively, were found in the hot-rolled 0.5 wt % Gd sample, which exhibits the optimum corrosion resistance as well.