Abstract: An austenitic steel comprising Ni of 9-30%, Cr of 10-23%, and Fe of at least 45%, is characterized in comprising enough Cr and Ni to form whole austenitic structure in the equilibrium diagram at 700.degree. C., having austenitic phase at room temperature, and the austenitic phase is a single crystal, and has superior resistance against stress. The austenitic steel preferably comprises C.ltoreq.0.1%, Si.ltoreq.1%, Mn.ltoreq.2%, Ni 9-15%, Cr 16-18.5%, and at least one of elements selected from the group of Mo 1-3%, Ti 0.05-1%, and Nb 0.1-1.5%. The alloy is useful as a material for members of a reactor core of a nuclear reactor.

Abstract: This invention relates to novel permanent magnet alloy compositions and high energy permanent magnets comprising from about 0.5 to about 27 atomic percent R wherein R is at least one rare earth element including Y and Sc, from about 0.1 to about 53 atomic percent A wherein A is at least one actinide element, and the balance being at least one metal wherein at least about 50 weight percent of the balance is at least one metal selected from the group consisting of Fe, Co, Ni, and Mn. Preferably, R is from about 12 to about 18 atomic percent and R is a rare earth element selected from the group consisting of Sm, Nd, Pr, and Dy. It is also preferred that A is from about 1.5 to about 5.1 atomic percent and A is an actinide element selected from the group consisting of Ac, Th, Pa and U. The balance is preferably at least about 90 weight percent of Fe and/or Co, and further comprises from about 0.1 to about 10 weight percent of Zr and/or Cu.