Ultrafine Eutectic-Dendrite Composite Bulk Fe-B Alloy with Enhanced Ductility

Abstract

that the yield strength and plasticity of Fe88Nb12 alloy were 1.4 GPa and 13.0%, respectively. Yield strength of 1.8 GPa and plasticity of 6.7% in the case of the Ti65Fe35 was obtained by Louzguine et al. 14) In summary, the structure of dendrite-ultrafine/nano composite can enhance the ductility of ultrafine/nano-structured materials. So, the dendrite-ultrafine/nano-structured Fe-B alloy was designed in this paper, which was expected to obtain high ductility. So far, there are only a few reports on the mechanical properties of the ultrafine/nano-structured Fe-B alloys. However, the mechanical behavior of the Fe-B alloys has important impact on industrial applications. In this letter, the dendrite-ultrafine eutectic composite Fe2B and Fe3B alloys were prepared by a self-propagating high temperature synthesis (SHS) combining rapid solidification technique. We investigated the relationship between the dendrite contents in the composite structure and the mechanical behavior. A small quantity of dendrites embedded in the ultrafine eutectic matrix can reinforce the ductility obviously. However, the ductility reduces when the content of dendrite is up to 90%. 2. Experimental Procedure The bulk Fe2B and Fe3B hypereutectic alloys were cast into a fully dendrite-ultrafine eutectic composite structure by a combination route of SHS processing and rapid solidification technique. This method was depicted in other literatures. 15–18) The polished cross sections were investigated by X-ray diffractometry (XRD, Philips X’pert) using