Influence of the alloying elements addition on the microstructure and hardness of Ni-Nb-M alloys system (M = Al, Ti, Cr, Fe)

Abstract

This work will study the microstructure and microhardness of a set of ternary Ni-Nb-M (M = Al, Ti, Cr, Fe) alloys, rapidly solidified by copper mold casting. The samples will be manufactured in a vacuum arc furnace in an argon gas atmosphere, using elements of high purity (99.9% Nb and 99.9% Ni) combined with the commercial Ni-alloy Ni-65%Nb donated by CBMM company. These alloys will be based on a previous study of Ni-xNb binary alloys, as there is still a gap in the literature to be explored regarding the microstructure and mechanical properties of crystalline Ni-Nb-M ternary alloys. The samples will be characterized by: X-ray diffraction (XRD), optical microscopy (MO), scanning electron microscopy (SEM) coupled to EDS (X-ray dispersive energy spectroscopy), thermal analysis (DSC), and, possibly, transmission electron microscopy (TEM) as well Vickers microhardness evaluation. This research will have collaborations from research groups in relation to the theme to be developed and will also be associated with the possibility of establishing a new line of research in DEMa / UFSCar, that of Ni-Nb based superalloys. The characterization of these laser processed materials will be facilitated by the infrastructure offered by the Metals Labs and Structural Characterization Laboratory (LCE) in conjunction with research laboratories from DEMa/UFSCar and the group on Nanocrystalline Metallic Alloys. It is expected to obtain clearer and more isolated responses of the effects of each alloying element and the effects of the second phases dispersed in the ³-Ni (fcc) matrix on the microhardness of the ternary Ni-Nb-M alloys.