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-c...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.展开更多
NiAl-28Cr-6Mo alloy was prepared by hot-pressing (HP) the atomized prealloyed powders. The results show that the powders have uniformly refined size and small interlamellar spacing; the porosity is the main defect in ...NiAl-28Cr-6Mo alloy was prepared by hot-pressing (HP) the atomized prealloyed powders. The results show that the powders have uniformly refined size and small interlamellar spacing; the porosity is the main defect in the powder metallurgy (PM) alloy, the Cr(Mo) phase in the alloy is easy to segregate to form network in the interior of the original powders and blocks at the boundaries of the original powders during the HP processing; the PM alloy exhibits a high-level combination of fracture toughness and tensile strength, whereas the creep resistance of the PM alloy is degraded.展开更多
文摘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.
文摘NiAl-28Cr-6Mo alloy was prepared by hot-pressing (HP) the atomized prealloyed powders. The results show that the powders have uniformly refined size and small interlamellar spacing; the porosity is the main defect in the powder metallurgy (PM) alloy, the Cr(Mo) phase in the alloy is easy to segregate to form network in the interior of the original powders and blocks at the boundaries of the original powders during the HP processing; the PM alloy exhibits a high-level combination of fracture toughness and tensile strength, whereas the creep resistance of the PM alloy is degraded.
