INFLUENCE OF LONG-RANGE ORDER ON TENSILE PROPERTIES OF NIOFE AND NI3FE-Y2O3 COMPOSITES

Ni3Fe is a compound that exhibits long-range ordering below 500-degrees-C an a disordered structure above this temperature. Thus, Ni3Fe allows study of the effect of ordering on mechanical properties. This paper discusses the tensile properties of Ni3Fe produced via powder metallurgical routes. Some samples subsequently were densified by containerless hot isostatic compaction. Ni3Fe was consolidated with elemental nickel and iron powders that were solid state sintered. Composites of Ni3Fe with 5 vol. % Y2O3 were prepared by presintering cold isostatically pressed rods, followed by containerless hot isostatic pressing. The influence Of Y2O3 particles on flow stresses of ordered and disordered Ni3Fe was determined. Ordering of Ni3Fe increased both strength and hardness with a small effect on ductility. For the Ni3Fe-Y2O3 CoMposite, the increase in the strength in both ordered and disordered matrix conditions was accomplished by a large reduction in elongation.