Abstracts Book - IMRC 2018

• SD7-P016
DETERMINATION OF THE CONTROL AGENT IN THE
NANOCRYSTALLINE MULTICOMPONENT SYSTEM
(ALCOCRFEMNNI).
Marco Antonio Ruiz Esparza Rodriguez 1 , Carlos Gamaliel Garay Reyes 1 , Jose Manuel Mendoza
Duarte 1 , Ivanovich Estrada 1 , Roberto Martinez Sanchez 1
1 Centro de Investigación en Materiales Avanzados, S.C., Metalurgia e Integridad Estructural,
Mexico.
Nanocrystalline materials have been studied due to the properties they offer
compared to conventionally materials, one of the methods to synthetize
nanocrystalline alloys is by means of the mechanical alloying (MA) process. By MA
it is possible to obtain nanocrystalline materials mainly in metallic alloys. The
process control agents (PCAs) are used in the MA process to maintain a balance in
the internal processes (fracture and cold welding) during milling. Therefore, this
work focuses on the evaluation of different PCA´s during the synthesis of a
multicomponent system. The equiatomic AlCoCrFeMnNi powders were processed
by mechanical alloying. Pure elements (each of them at least 99.9% purity) were
used as the raw material. The millings were performed by using a high energy mill
Spex 8000. In order to investigate the effects of PCA on the mechanical alloying
mechanism, methanol, n-heptane and stearic acid were chosen as PCAs. The study
of particle size distribution, morphology and oxidation of multicomponent system
was carried out by means of a Malvern2000 laser dispersion system, a scanning
electron microscope HITACHI SU3500, a transmission electron microscopy (TEM), a
thermogravimetric analyzer SDT Q 600 TA and elemental analyzer CHNS-O CE EA
1110. The oxygen quantification results shown that the contamination depends on
the chemical composition of the molecule that represents the control agent, so the
best results were obtained with n-heptane since its molecule only contains carbon
and hydrogen. Respecto to response to temperature, the n-heptane showed lower
values in its weight gain. The structural characterization shows that the change of
control agent does not have influence in the crystal structure maintaining an FCC
system. It is concluded that AlCoCrFeMnNi alloy powder oxidation can be reduced
by the use of n-heptane, however a larger particle size is obtained in comparison to
the obtained by methanol, since methanol reduces the cold welding process and
increases the fracture events.
Keywords: Multicomponent System, Process Control Agent, Mechanical Alloy
Presenting authors email: marco.ruiz@cimav.edu.mx