Autor: ROBERTO MARTINEZ SANCHEZ

Simultaneous effect of mechanical alloying and arc-melting processes in the microstructure and hardness of an AlCoFeMoNiTi high-entropy alloy

ROBERTO MARTINEZ SANCHEZ (2015)

A nanostructured AlCoFeMoNiTi high entropy alloy was synthesized through the mechanical alloying process. Bulk samples were obtained by two different routes to compare the microstructural evolution and hardness behavior: sintering and arc melting. Through electron microscopy analyses the formation of Mo-rich and Ti-rich phases were identified in the melted sample, while Ti-rich nano-precipitates were observed in the sintered sample. A higher microhardness value was achieved on the sintered sample than for the melted sample. The disadvantage of porosity in the sintered sample in comparison to the melted one was overcome by the hardening effect produced by the mechanical alloying.

Artículo

High entropy alloys; Mechanical alloying; Arc melting; Microstructure BIOLOGÍA Y QUÍMICA QUÍMICA

Characterization of Al2O3NP–Al2024 and AgCNP–Al2024 composites prepared by mechanical processing in a high energy ball mill

ROBERTO MARTINEZ SANCHEZ CALEB CARREÑO GALLARDO MARIO ALBERTO ROMERO ROMO (2012)

Mechanical alloying was used to produce two kinds of metal matrix composites based on 2024 aluminum alloy. The nanocomposites were reinforced with different percentages of Al2O3 and AgC nanoparticles. The content of nanoparticles has an important role on the mechanical properties of the nanocomposites. A milling time of 10 h is enough to form the Al2024 nanocomposites. The thermograms obtained by differential scanning calorimeter show the temperatures of phase precipitation, which were identified by X-ray diffraction. The results revealed that mechanical alloying is an excellent route for the incorporation and distribution of nanoparticles into Al2024.

Artículo

Mechanical alloying; Nanocomposites; Reinforcement BIOLOGÍA Y QUÍMICA QUÍMICA

Effect of Cr, Mo and Ti on the microstructure and Vickers hardness of multi-component systems

ROBERTO MARTINEZ SANCHEZ IVANOVICH ESTRADA GUEL (2014)

This study reports the synthesis of multi-component systems by mechanical alloying, their subsequent

consolidation by conventional sintering followed by mechanical and microstructural characterization.

Three multi-component systems were selected and the effect of Cr, Mo and Ti is reported. Mechanical

alloying leads to formation of nanocrystalline powder alloys of about 5–25 nm after 10 h of milling.

XRD patterns indicate the presence of several solid solution phases with BCC and FCC structures in both

the as-milled and the sintered products. After the sintering process, new equilibrium phases are crystallized

from milled powder. Crystallized phases present simple structures (BCC and FCC) but with some differences

in composition, besides tetragonal and/or rhombohedral structures in alloys with Cr and Mo.

High hardness values are found in consolidated samples. Alloying elements, grain size, proportion and

nano-size of dispersed phases have an important effect on mechanical properties.

Artículo

Metals and alloys; Mechanical alloying; Sintering; Mechanical properties; Microstructure BIOLOGÍA Y QUÍMICA QUÍMICA