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

Abstract

Bulk Fe 2 B and Fe 3 B alloys have been prepared by a self-propagating high temperature synthesis combining rapid solidification technique. The Fe 2 B and Fe 3 B alloys are composed of t-Fe 2 B dendrite and ultrafine eutectic matrix with t-Fe 2 B and -Fe, and the dendrites are rounded by the matrix. The volume fractions of the dendrite of the Fe 2 B and Fe 3 B alloys are 90% and 20%, respectively. The fracture strength reduces from 3400 MPa to 2660 MPa with the increase of dendrite content, but the strain at fracture rises markedly from 3% to 19%. The result indicates that a small quantity of dendrites embedded in the ultrafine eutectic matrix can reinforce the ductility.