Microstructure and mechanical properties of Nb-doped NiAl-Cr(Mo) eutectic prepared by injection casting
(1.Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China2.Department of Materials Engineering, Dalian University of Technology, Dalian 116024, China)
Abstract: The microstructure, compressive properties at different temperatures and hardness of NiAl-Cr（Mo）-Nb alloy prepared by injection casting were investigated. Compared with the conventionally-cast alloy, the injection-cast alloy exhibits a fine microstructure, i.e. the fine eutectic cell and interlamellar spacing as well as fine primary NiAl phase and NbCr2-type Laves phase due to the high cooling rate. In addition, the area fraction of eutectic cell increases due to the narrow intercellular zone. The Vickers hardness of injection-cast alloy is markedly enhanced. The ductility and strength at room temperature are increased by 88% and 30% compared with those of conventionally-cast alloy respectively. However, the high-temperature strength of injection-cast alloy is not improved markedly. The elevated temperature compression deformation behavior can be properly described by power-law equations.
Key words: NiAl-Cr(Mo)-Nb alloy； injection casting； microstructure； mechanical properties