Glass-Forming Ability and Mechanical Properties of Sm-Doped Fe–Cr–Mo–C–B Glassy Alloys

Abstract

Glass-forming ability and mechanical properties of Fe 43 Cr 16 Mo 16 C 15 B 10x Sm x alloy were systematically studied in terms of the effect of substitution of rare-earth element Sm for the metalloid element B from 0 to 6 at%. It was found that the thermal stability and glass-forming ability of studied alloys were greatly enhanced by the replacement of B with Sm. With merely 1 at%Sm addition, the supercooled liquid region was extended from 66 to 88 K, and the diameter of the cast rod with fully glassy state increased from 1.5 to 4 mm. When the Sm content is in the range of 2 to 4 at%, the critical diameter for glass formation further increased up to 5 mm. The mechanical properties were also greatly improved by the Sm additions. The Young's modulus and compressive strength increase respectively from 140GPa and 2400MPa for the Fe 43 Cr 16 Mo 16 C 15 B 10 alloy to 189GPa and 3400MPa for the Fe 43 Cr 16 Mo 16 C 15 B 8 Sm 2 alloy. However, no improvement in plasticity was observed in the Sm-added glassy alloys. Similar to the Sm-free glassy alloys, the Sm-doped glassy alloys deformed inhomogeneously and failed in a brittle manner. The mechanism for the improved GFA by the addition of Sm is discussed.