Mechanical Properties and Oxidation Behavior of Hot Pressing Sintered Nb5Cr Superalloy

Abstract

In this paper, an alloy with a group of Nb5Cr was prepared by hot pressing sintering and its phase composition was characterized. After hot pressing sintering, Cr element exists in the form of solid solution outside the Nb matrix, and a certain amount of NbCr₂ phase is formed. The bending strength of the obtained alloys is not less than 250 MPa, and the fracture toughness is close to that of H11 casting die steel. In addition to the mechanical properties of the alloy, the oxidation behavior of the alloy at different temperatures was also studied. The experimental results show that the change of the alloy is not obvious at 1000°C except for the dissolution of Cr element, and at 1000–1200°C, the alloy can spontaneously form a CrNbO₄ oxide film which is weakly bound to the alloy matrix. This is very conducive to the application of separation between the mold and the casting mold during casting. This product provides the casting industry with a material that can spontaneously form a Self-oxidizing film under high temperature oxidation environment and provides a usable choice for materials used in high temperature casting environment.