Ultrafine eutectic-dendrite composite bulk Fe-B alloy with enhanced ductility

Bulk Fe₂B and Fe₃B alloys have been prepared by a self-propagating high temperature synthesis combining rapid solidification technique. The Fe₂B and Fe₃B alloys are composed of t-Fe₂B dendrite and ultrafine eutectic matrix with f-Fe₂B and α-Fe, and the dendrites are rounded by the matrix. The volume fractions of the dendrite of the Fe₂B and Fe₃B 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.