Microstructure and mechanical properties of rapidly solidified NiAl-based eutectic alloy
(1.Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China2.School of Mechanics and Automobile, Shenyang Institute of Aeronautical Engineering, Shenyang 110034, China3.中国科学院金属研究所，沈阳110015)
Abstract: The microstructure and compression behavior at room temperature of a rapidly solidified NiAl-Cr（Mo）-Hf eutectic alloy fabricated by water-cooled copper mold method were studied by a combination of SEM, EDS and compressive tests. The rapid solidification results in a shift in the coupled zone for the NiAl-Cr（Mo）-Hf eutectic alloy towards the side of Cr（Mo） phase. So the volume fraction of primary NiAl dendrite is increased which is detrimental to the mechanical behavior. On the other hand, the refined microstructure and fine dispersion Heusler phase by Ni2AlHf are beneficial to the improvement of mechanical properties. As a result, the strength increases by 40% and the compressive ductility increases by two times at room temperature, when compared with those of the as-cast state.
Key words: rapid solidification； nickel aluminide； eutectic； microstructure