High energy product rare earth-transition metal magnet alloys containing boron

Magnetically hard compositions having high values of coercivity, remanence and energy product contain rare earth elements, transition metal elements and boron in suitable proportions. The preferred rare earth elements are neodymium and praseodymium, and the preferred transition metal element is iron. The magnetic alloys have characteristic very finely crystalline microstructures, in which there is present a tetragonal crystal phase with an atomic formula of RE2TM14B1, in which: RE represents one or more rare earth elements, with neodymium and or praseodymium comprising at least 60 atomic percent thereof; and TM represents one or more transition metal elements, with iron ornprising at least 60 atomic percent thereof.