An alloy composition is composed essentially of Hf.sub.2-XZr.sub.XCo.sub.11B.sub.Y, wherein 0<X<2 and 0<Y.ltoreq.1.5. Moreover, an alloy composition is composed essentially of ferromagnetic Hf.sub.2-XZr.sub.XCo.sub.11B.sub.Y, wherein 0.ltoreq.X<2 and 0<Y.ltoreq.1.5, and has a nanoscale crystalline structure comprising at least one non-equilibrium phase. The alloys can be melt-spun with in-situ and/or ex-situ annealing to produce the nanoscale crystalline structure.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
 The United States Government has rights in this invention pursuant to contract no. DE-AC05-00OR22725 between the United States Department of Energy and UT-Battelle, LLC.