Функциональные свойства моно- и поликристаллов высокотемпературного сплава Ni50,3Ti32,2Hf17,5

Abstract

Thermoelastic martensitic transformations were investigated in single crystals and polycrystals of high-temperature Ni50,3Ti32,2Hf17,5 alloy. It was shown, that functional properties, such as strain, thermal hysteresis, characteristic temperatures, superelasticity are different in single crystals and polycrystals. The inner microstructure provides either low characteristic temperature, decreasing hysteresis, difficult generation and easy growth of martensite in single crystals or high characteristic temperatures, increasing hysteresis, easy generation and difficult growth of martensite in polycrystals. Besides, it was suggested, that large coefficient α, that characterizes the growth of stress with the increase of temperature Ms, in combination with wide thermal hysteresis result in the absence of superelasticity in polycrystals.