Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
Plasma Nitriding of Fe-Al Ferritic Alloys at 500 and 550 ºC
Submission Author:
Fernando Irto Zanetti , SC
Co-Authors:
Leonardo Luis Santos, Igor Zanella, Guilherme Seiti Kobayashi, Silvio Francisco Brunatto, Rodrigo Perito Cardoso, Fernando Irto Zanetti
Presenter: Fernando Irto Zanetti
doi://10.26678/ABCM.COBEM2017.COB17-2407
Abstract
The low-temperature thermochemical treatments are highlighted due some particularities of the formed phases. Some of these, known as metastable phases, are obtained by carrying the treatment at specific conditions in which the carbide or nitride formers elements present in solid solution in the alloy has negligible mobility when compared with carbon or nitrogen. This condition of metastability its achieved by its low mobility, low solubility of the aluminium in the iron nitrides and to the elevated constrains imposed by the ferritic matrix over the stable Al nitride, i.e. hexagonal aluminium nitride. In some conditions this treatments leads to situations of supersaturation which promote a saw layer growth of precipitates. To better understand the change in treated layer morphology, samples of Fe-Al ferritic alloys with 0, 1, 3, 5, 7 and 10 wt. % Al were plasma nitrided at 500 and 550 ºC for 4 hours. Preliminary results reveal, besides the saw like layer, a homogeneous layer for contents over 5 wt. % at 500 ºC and above 3 wt. % Al at 550 ºC, this layer exhibits a thickness of more than 100 μm with 1500 HV0,1 Vickers hardness, moreover the confocal measurement reveal a surface texture related to the saw like morphology. The XRD indicate the precipitation of a phase similar to Cubic AlN, however at the temperature of 550 ºC the formation of a thin layer of Fe2-3N on the surface is observed, exhibiting a behaviour similar to a treatment in thermodynamic equilibrium.
Keywords
plasma nitriding, Fe-Al Nitriding, Cubic AlN, Nitride Former, Me-N Interaction, Low Temperature Nitriding
