Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
PROCESSING OF NiAl INTERMETALLIC COATINGS MODIFIED WITH Fe AND Cr.
Submission Author:
Heber Abreu Castillo , PR
Co-Authors:
Heber Abreu Castillo, Ana Sofia D'Oliveira
Presenter: Heber Abreu Castillo
doi://10.26678/ABCM.COBEM2021.COB2021-2296
Abstract
NiAl aluminide intermetallic coatings are used in many industries mainly for their resistance to high temperature environments. Performance associated with their ordered crystal structure, low density and the ability to form a continuous and adherent protective film of alumina. Different alloying elements have been studied to enhance the competitiveness of NiAl. Carbides such as WC or elements such as Fe and Cr have been shown to increase hardness, improving the tribological behavior of NiAl alloys. The aim of the present work is to understand how these alloying elements affect the microstructure and mechanical properties of NiAl intermetallic coatings processed by in-situ synthesis during Plasma Transferred Arc (PTA) processing. Alloying elements were added both by the interaction with the stainless steel substrate (Cr and Fe) and the addition of 1wt% of carbides (W and C) to the Ni+Al powder mixture. The strong interaction with the substrate caused dual phase coatings of β-NiAl and γ-FeNi phases in agreement with predictions based on the ternary Ni-Al-Fe alloy system. W carbides in the elemental powder mixture induced a greater dilution with the substrate favoring the increase in Fe and Cr content. Changes in composition of coatings resulted in an increase in the austenite phase and the presence of point defects in the NiAl crystalline structure, which brought a significant increase in hardness.
Keywords
aluminides, Plasma Transferred Arc, alloying elements, Intermetallics, Coatings
