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 43Cr16Mo16C15B10xSmx 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 140 GPa and 2400 MPa for the Fe43Cr 16Mo16C15B10 alloy to 189 GPa and 3400 MPa for the Fe43Cr16Mo16C 15B8Sm2 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. © 2005 The Japan Institute of Metals.