Abstracts Book - IMRC 2018

• SE5-O023
INFLUENCE OF THE PHASES γ’-Fe4N and ε-Fe2-3N ON THE
CHEMICAL, MECHANICAL AND TRIBOLOGICAL PROPERTIES OF
TOOL GRADE STEEL AISI M2: THEORETICAL-EXPERIMENTAL
STUDY
Víctor Manuel Hurtado Pájaro 1,2 , Juan Emiliano Galván Chaire 1 , Alma Martínez Hernández 1 ,
Juan Manuel Alvarado Orozco 1
1 Centro de Ingeniería y Desarrollo Industrial, Surface Engineering, Mexico. 2 Universidad
Tecnológica de Querétaro, Nanotechnology Engineering, Mexico.
During the service of tool grade steels, these are usually subjected to thermal
stresses that can cause failures due to fatigue, wear and corrosion. The
application of suitable surface treatments has become necessary to improve the
tribological properties and performance of the material. One of them, is plasma
assisted nitriding. This thermochemical treatment is based on the interstitial
diffusion of nitrogen and process parameters such as gas pressure,
temperature and processing time. One of the main characteristics of the process
is the formation of γ’-Fe 4 N and ε-Fe 2-3 N phases. Also called “compound layer”.
The control of the formation of this layer is of our particular interest because
they improve fatigue resistance as well as other performance properties, such
as corrosion and wear resistance.
However, the nature of the thermodynamic phenomenon referred to the
formation of the compound layer in AISI M2 tool grade steel has not been fully
understood.
In the present work, were investigated the effect of the plasma-assisted nitriding
time on the mechanical and tribological properties of an AISI M2 steel. All the
plasma treatments were carried out in an atmosphere of Ar:N 2 :H 2 under a
stoichiometric ratio of 6:2:1, in a temperature range of 350ºC to 390ºC, with
processing times of 1.0, 1.5, 2.5 hours. Thermo-Calc® and DICTRA® software
were used to determine the formation of phases taking into account the
parameters of the process. The results were related to those obtained in the X-
Ray Diffraction (XRD). The morphology of the surface was analyzed by Optical
and Scanning Electronic Microscopy (OM, SEM). The elemental composition
profiles were obtained through Glow Discharge Optical Emission Spectroscopy
(GDOES) and Energy Dispersive Spectroscopy (EDS). Mechanical and tribological
measurements were obtained by nanoindentation and scratch test.