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Hector Javier Vergara Hernández

Hector Javier Vergara Hernández
Tecnológico Nacional de México/Instituto Tecnológico de Morelia · Division of Postgraduate Studies and Research (DEPI).

Doctor of Engineering

About

118
Publications
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296
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Introduction
Simulation and optimization of metal manufacturing and transformation process, applying microstructural engineering and knowledge of amount of movement, heat and mass transport. We are currently working through a consortium of public universities called SEDEAM National Laboratory, to provide solutions to sectors of government, private initiative and social environment.

Publications

Publications (118)
Article
The kinematics of the wetting front, i.e., the loci of the boundary between stable vapor film and the presence of bubbles, during quenching operations largely determines the evolution of the microstructural and displacement fields which, in turn, control the properties of the quenched product. Thus, it is important to develop techniques that allow...
Conference Paper
Full-text available
Resumen Los materiales más utilizados para la fabricación de implantes son el acero inoxidable 316L, CoCrMo y Ti6Al4V. Cada uno de ellos posee características que les permiten cumplir de manera aceptable su tarea de remplazar un hueso. Sin embargo, la combinación de dos o más de ellos podría generar un material que ayude a mejorar el desempeño y du...
Conference Paper
Full-text available
Resumen Un compuesto de Ti6Al4V reforzado con partículas de CoCrMo es obtenido mediante pulvimetalurgia convencional y sinterización en estado semi-sólido. Los compuestos se fabrican mezclando diferentes fracciones de volumen de partículas de CoCrMo (10-30 % vol.) como partículas de refuerzo en la matriz de Ti6Al4V. La sinterización se estudia medi...
Conference Paper
Full-text available
Resumen Los materiales más utilizados para la fabricación de implantes son el acero inoxidable 316L, CoCrMo y Ti6Al4V. Cada uno de ellos posee características que les permiten cumplir de manera aceptable su tarea de remplazar un hueso. Sin embargo, la combinación de dos o más de ellos podría generar un material que ayude a mejorar el desempeño y du...
Conference Paper
Full-text available
This work presents a methodology to produce materials with specific properties by conventional powder metallurgy route. The fabricated component is a dental implant based on Ti6Al4V powders, with different microstructures and properties that will allow a better and faster osseointegration. This component is made of three different layers, an upper...
Article
Full-text available
We present a novel Ti64/20Ag highly porous composite fabricated by powder metallurgy for biomedical applications and provide an insight into its microstructure and mechanical proprieties. In this work, the Ti64/20Ag highly porous composites were successfully fabricated by the space holder technique and consolidated by liquid phase sintering, at low...
Article
This research work aimed to determine the hydrogen gas pressure effect on the mechanical properties of an experimental X-120 microalloyed steel, subjected to heat treatments and quenched in different mediums. The steel in its as-received condition was reheated at 900 °C and quenched in spray water (900QSW), pressurized air (900QPA), and emulsion of...
Article
Full-text available
Optical decarburization measurements are preferred for quality tests, modeling, or indirect methods over carbon steel products. The measurements are commonly done by metallographs and can be supported by image processing. Image processing allows the collection of multiple measurements from digital micrographs. Nevertheless, limited attention has be...
Article
Hydrogen permeation tests are carried out to evaluate the effect of the quenching medium and tempering temperature on the permeation parameters and density of hydrogen traps, of a Cr–Mo–V low-alloy medium-carbon steel. Three types of steel membranes are tested: 1) in the as-quenched condition, 2) tempered at 235 °C and 3) tempered at 530 °C; each o...
Article
Full-text available
El presente documento introduce una metodología para la medición de profundidad de capa descarburada en metalografías usando procesamiento de imágenes. La metodología utiliza como base el software ImageJ y funciones de procesamiento del propio software, así como propias. El procesamiento de las imágenes digitales (metalografías) pasa por un preproc...
Patent
Full-text available
La invención se refiere a un dispositivo para la medición de la expansión y/o contracción térmica lineal de una probeta metálica cilíndrica hueca de estructura cristalina sometida a un tratamiento térmico. El procedimiento de medición de la probeta de trabajo depende de las rampas de calentamiento y enfriamiento programadas por el usuario a través...
Patent
Full-text available
El dispositivo presentado en esta invención mide la expansión y/o contracción térmica lineal de una probeta metálica cilíndrica hueca de estructura cristalina sometida a un calentamiento mediante el efecto Joule. La probeta está montada a un sistema de sujeción que cuenta con un par de mordazas porta-electrodo que permiten realizar el calentamiento...
Article
Pitting corrosion in stainless steel (SS) is a punctual defect that promotes fatigue and cracks propagation. Martensitic steel of steam turbine is exposed to the thermal cycle of welding, high pressures, and corrosive environments in the heat-affected zone (HAZ). The presence of δ-ferrite in HAZ causes crystalline grain boundaries sensitization and...
Article
Full-text available
This study reported a theoretical-experimental analysis of dissimilar metals duplex stainless steel (DSS) grade 2205 and twinning induced plasticity (TWIP) steel joined. Welded joints were performed in autogenous mode and using filler metal (ER2209) by the pulsed gas tungsten arc welding (GTAW-P) process. Critical weld regions were characterized me...
Article
Full-text available
A non-isothermal transformation model was proposed to determine the austenite formation kinetics in a steel alloyed with 2.6% wt. Si by dilatometric analysis, considering that the nucleation mechanism does not change with the heating rate. From the dilatometric analysis, it was observed that the austenite formation occurs in two stages; critical te...
Article
Full-text available
The austenite formation kinetics of a low–carbon steel under two initial conditions—annealed and cold– rolled (0.08C–1.22Mn–0.73Si) were determined by dilatometric analysis during continuous heating. In both conditions, the austenite formation occurred in two stages. The critical transformation temperatures are a function of the heating rate but no...
Article
Full-text available
High-temperature surface oxidation kinetics were determined for low-carbon steel using a Joule heating device on hollow cylindrical specimens. The growth of the oxide layer was measured in situ between 800 and 1050 ∘C under isothermal oxidation conditions and in an air laboratory atmosphere (O2 = 20.3% and humidity = 42%). Through a laser and infra...
Article
Full-text available
The medium frequency transformer (MFT) with nanocrystalline alloys is quintessential in new DC–DC converters involved in various front-end applications. The center piece to achieve high-performance, efficient MFTs is the core. There are various options of core materials; however, no deep information is available about which material characteristics...
Conference Paper
Low-carbon steels alloyed with Si and Mn are used in welding electrodes manufacture, due to their ductility, weldability, mechanical resistance, and toughness, all of which depend on microstructure and mechanical properties, associated in turn with austenite decomposition kinetics. Due to this, there is great interest in controlling phase formation...
Article
Microalamabres de Zn − 22%Al − 4%Ag, obtenidos por rolado y trefilado se caracterizaron mediante difracción de Rayos-X (DRX) de manera cualitativa y cuantitativa, a la par se observaron mediante Microscopía Electrónica de Barrido (MEB). Los resultados se compararon con microalambres obtenidos del proceso de solidificación rápida por tambor rotativo...
Article
Full-text available
Hot cracking susceptibility and the formation of brittle martensite phase are the main factors that limit the weldability of a dissimilar joint between carbon steel (CS) and austenitic stainless steel (SS). In this study, the self-constraint finger test was used to correlate the welding thermo-mechanical field with the crack susceptibility of a dis...
Article
Full-text available
Stainless steels are used to manufacture components for the automotive industry, equipment and components of steam turbines for the generation of electrical energy; for this reason, it is important to consider the percentage of martensite and microhardness obtained after applying the arc welding processes. In this paper, specific variations of volt...
Article
This work presents a novel methodology to produce materials with specific properties by powder metallurgy. The fabricated implant prototype, based on Ti6Al4V powders, is composed of three different layers, one with high hardness, a core with large pores and the outer shell with smaller pore size. Interphase bonding was very good, mechanical propert...
Article
Full-text available
A detailed experimental and numerical investigation was performed on a Ti6Al4V/xCoCrMo biomedical composite for bone implant applications. The aim was to understand the effect generated by the addition of different volume fractions of CoCrMo particles on a Ti6Al4V matrix composite processed by powder metallurgy. Distribution of CoCrMo particles ins...
Conference Paper
Full-text available
The effect of tempering temperature on the martensite softening in an experimental low-alloy medium carbon steel was studied by dilatometric analysis under isothermal conditions. AISI / SAE 4140 steel was chemically modified by adding molybdenum and vanadium ferroalloys. The experimental steel microstructure was conditioned to determine the temperi...
Article
This work investigates the fabrication of Ti6Al4V/xAg composites processed by powder metallurgy. An atomized Ti6Al4V powder was blended with 0, 5, 10, 15 and 20 vol.% of Ag particles, compacted in a die, and sintered above Ag melting point. The compressibility of the mixtures was analyzed, and the sintering kinetics was evaluated by dilatometry tes...
Article
Full-text available
Steel’s transformation is crucial for quality improvement. The high-temperature reheating process is usually performed under oxidizing atmospheres. Therefore, decarburization is present, resulting in material losses and depreciating the material’s quality. The decarburization depth is commonly used to authenticate the quality of steel or develop pr...
Article
Gas nitriding was used to coat highly porous compacts of Ti6Al4V alloy, and in this work, for the first time, the nitrogen diffusion process was evaluated by means of dilatometry tests. Nitriding was performed between 950 and 1250 °C with a dwell time of 1 h, and the axial deformation was measured during the whole thermal cycle. Coating thickness w...
Preprint
Full-text available
Hot cracking susceptibility and the formation of brittle martensite phase are the main factors that limit the weldability of a dissimilar joint between carbon steel (CS) and austenitic stainless steel (SS). In this study, the self-constraint finger test was used to correlate the welding thermo-mechanical field with the crack susceptibility of a dis...
Article
Full-text available
The semi-solid sintering of a novel Ti6Al4V/CoCrMo biomedical composite was investigated for the first time by semi-in situ X-ray computed microtomography. Composite was fabricated by dry mixing 15 vol% CoCrMo reinforcing particles with Ti6Al4V particles as matrix. The mixture was poured into a 1 mm diameter quartz capillary. 3D images of the same...
Chapter
A medium-carbon steel alloyed with vanadium was analyzed by differential dilatometryDilatometry, microhardness and nanoindentationNanoindentation to characterize the fourth temperingTempering stage or secondary hardeningSecondary hardening zone. From isochronal heating paths at different tempering temperatures, the secondary hardeningSecondary hard...
Chapter
TemperingTemperingkineticsKinetics of the martensite was determined using the Johnson–Mehl–Avrami model in a Cr–Mo–V alloyed medium-carbon steel by dilatometry. Tempering temperatures were determined by non-isothermal analysis at constant heating rate. From these temperatures, isothermal tempering was carried out. The reaction stages were associate...
Article
A microstructural analysis was performed to determine the presence of oxygen in a wire rod section of AISI 1008 steel with a surface mechanical failure produced during wire drawing. The failure zone was analyzed by comparison using three different attack reagents: alkaline sodium chromate (ASC), ASC with hydrogen peroxide and amyl alcohol, and a so...
Article
Full-text available
A coupled thermal-microstructural simulation model was developed to estimate the thermal history in a eutectoid steel wire rod under continuous cooling and forced-convection. The model coupled the phenomena of heat transfer, phase transformation and estimation of the cooling boundary condition. The thermal histories were analyzed at different cooli...
Article
Full-text available
A new processing route is proposed to produce graded porous materials by placing particles of Ti6Al4V with different sizes in different configurations to obtain bilayer samples that can be used as bone implants. The sintering behavior is studied by dilatometry and the effect of the layers’ configuration is established. To determine pore features, S...
Article
Full-text available
The aim of this work was to develop a Ti6Al4V/20CoCrMo−highly porous Ti6Al4V bilayer for biomedical applications. Conventional powder metallurgy technique, with semi-solid state sintering as consolidation step, was employed to fabricate samples with a compact top layer and a porous bottom layer to better mimic natural bone. The densification behavi...
Article
Because of the high demand for dual-phase (DP) steels in the automotive and construction industry, the present investigation focused on evaluating the corrosion resistance of three different commercial DP steels through electrochemical corrosion tests in conventional media (0.5 M NaOH, 3.5 wt.% NaCl, and 0.5 M H2SO4 solution). The potentiodynamic p...
Research
Full-text available
El presente reporte muestra la actualización del comportamiento de los casos reportados como confirmados de COVID–19 por la Secretaría de Salud (SS) de México desde el 23 de marzo, cuando el Laboratorio Nacional SEDEAM inicio el reporte. Día a día se actualizan en el repositorio, con la intensión de monitorear la evolución de la PANDEMIA en nuestro...
Technical Report
Full-text available
Campos 11 de abril del 2020 Introducción El presente reporte muestra la actualización del comportamiento de los casos reportados como confirmados de COVID-19 por la Secretaría de Salud (SS) de México desde el 23 de marzo, cuando el Laboratorio Nacional SEDEAM inicio el reporte. Día a día se actualizan en el repositorio, con la intensión de monitore...
Chapter
The Martensite decomposition by stages was studied in an experimental medium-carbon Steel alloyed with vanadium under conditions of Continuous heating and differential dilatometry. For the Dilatometric analysis, cylindrical specimens of 5 mm diameter and 15 mm length were machined and heated at different rates: 0.58, 0.75 and 0.91 °C s−1 until reac...
Article
Full-text available
Resumen: La determinación de los parámetros eléctricos y funcionales para aplicación de soldadura requiere realizar pruebas preliminares tanto en la industria como en la investigación. Sin embargo, este proceso resulta ser muy costoso, lento y, para objeto de investigación, de baja confiabilidad, por tal motivo, el desarrollo de una metodología de...
Article
Full-text available
This work shows the influence of the normal anisotropy (“r” value) in the deep drawing of AISI 439 ferritic stainless steel sheets. In order to do so, quantitative chemical analysis, metallographic analysis, tensile mechanical properties, and the determination of the “r” value and the “n” value were carried out in two different AISI 439 steel sheet...
Conference Paper
One steel containing 0.6 wt pct C, 0,78 wt pct Mn, and 0.32 wt pct Cr was austenitized at 840 oC for 1 hour and cooled at two rates. Microstructural evaluation by light optical and scanning electron metallography showed a change in the pearlite microstructure. Cooling in air as compared to furnace cooling reduced the pearlite interlamellar spacing...
Conference Paper
The influence of the hardening mechanisms by solid-solution and grain size on the ferrite nanohardness was analyzed in a low-carbon steel. A low-carbon steel alloyed was used to determine the effect of the composition on the ferrite nanohardness. The surface of each specimen was polished by vibration with colloidal silica suspension to obtain stres...
Conference Paper
In this work, continuous cooling treatments were carried out in steels with 0.75% C, with the aim of characterizing the spheroidal pearlite obtained in slow cooling treatments and its relationship with the ultimate tensile strength (UTS). With the use of Scanning Electron Microscopy, the pearlite interlamellar spacing for each cooling condition was...
Article
The design and fabrication of a bilayer Ti6Al4V–Ti6Al4V/30Ta component were performed by using the powder metallurgy process and solid-state sintering as the consolidation step. Phase change and sintering densification of the component were studied by dilatometry. The addition of 30 vol% of Ta to the Ti6Al4V matrix had a noticeable effect over the...
Patent
Full-text available
(EN): The invention relates to a process for preparing a homogeneous zirconium oxide coating on both faces of a steel substrate, imparting thereto the properties of generating hydrogen via alkaline water electrolysis, being more resistant to corrosion and increasing the generation of gas during the alkaline hydrolysis. During this process, the alre...
Patent
Full-text available
The invention relates to a process for preparing a homogeneous zirconium oxide coating on both faces of a steel substrate, imparting thereto the properties of generating hydrogen via alkaline water electrolysis, being more resistant to corrosion and increasing the generation of gas during the alkaline hydrolysis. During this process, the already co...
Article
Full-text available
Ohmic heating is currently a method with a wide potential as an alternative thermal process in the industry. However, the success of this method depends on the rate of the generated heat by the selected material and its geometry. The heating systems are usually modeled by CFD or FEM. In this paper a model that does not consider the temperature grad...
Conference Paper
Full-text available
En este trabajo se realizó el estudio del enfriamiento por convección forzada en piezas cilíndricas de acero AISI 304 con diferentes diámetros, bajo condiciones de presión y velocidad de aire controladas. Se construyó un modelo experimental donde se calentaron piezas hasta 950 °C y se les suministró aire forzado a diferentes velocidades para grafic...
Chapter
A medium-carbon steel with different silicon content was studied by dilatometric analysis during continuous heating. The critical transformation temper- atures were determined from the dilatometric curves and linear regression method, applied to the dilatometric behavior and the first derivative as a function of tem- perature. It was observed that...
Article
Full-text available
A composite of Ti6Al4V reinforced with CoCrMo particles is fabricated by conventional powder metallurgy and semi-solid sintering. Composites are fabricated by mixing 20% wt. of CoCrMo reinforcing particles into the Ti6Al4V matrix. Sintering is studied by dilatometry tests between 1050 and 1130 °C and compact characterization is performed by SEM and...
Article
A model was developed to predict the formation of austenite and dilatometric behavior during continuous heating in AISI 1045 steel, which has an initial microstructure composed of ferrite and pearlite. The model is proposed in two parts based on the heating rate and steel behavior to estimate the volume fraction of austenite during continuous heati...
Article
Ti6Al4V powders with three different particle size distributions (0–20, 20–45, and 45–75 μm) were used to evaluate the effect of the particle size distribution on the solid-state sintering and their mechanical properties. The sintering kinetics was determined by dilatometry at temperatures from 900 to 1260°C. The mechanical properties of the sinter...
Conference Paper
The signal compensation was performed for two temperature sensors, an infrared pyrometer and a K-type thermocouple, which are used to measure and control the temperature in an experimental dilatometer by Joule heating and controlled atmosphere. Sensor signals were corrected by compensation polynomials determined experimentally and encoded in LabVIE...
Conference Paper
An experimental and numerical study was carried out to analyze the effect of cooling micro-fins on the heat transfer coefficient in 6061 aluminum sheets subjected to a constant heat flow in a Joule heating system. For the numerical simulation, two User Defined Functions were implemented in a commercial program to solve the constitutive transport eq...
Conference Paper
Steel is a material that, depending of the chemical composition and subsequent processes, can show an extraordinary complexity in terms of microstructure. This complexity in terms of microstructure makes the steel a very versatile material, but at the same time, understand mechanical properties at a microstructural scale requires nontraditional tec...
Poster
Full-text available
Currently, the search for new renewable energies is the principal goals of developed and sub-developed countries. It is necessary to use economically competitive, technologically feasible and clean alternative energy sources for the environment; hydrogen is an alternative. However, the main challenge at present is to produce, store and transport it...
Conference Paper
Full-text available
The effect of the chemical composition and the rapid tempering parameters: temperature, heating rate and tempering time, on the microhardness were studied in two martensitic steels. For this, two medium carbon commercial steels were used; one alloy with chrome-molybdenum and the other unalloyed. The thermal parameters of quenching and rapid temperi...
Article
A method was established to determine the amount of austenite formed, by stages, in a low-carbon steel through dilatometric analysis. Based on length change measurements according to the temperature at different heating rates, the critical transformation temperatures were determined using the extrapolation method, intersection of lines, and first d...
Article
The present work shows the results of a numerical simulation, in the transient 3D state, of heating a block of stainless steel AISI 304 in continuous movement in the interior of an experimental vertical furnace. The model considers the heat transfer by radiation between the furnace walls and the surface of the block using the model P-1, implemented...
Article
Full-text available
Abstract: By formulating a mathematical model solved with the finite element method of the roller burnishing process, the effect of force, number of passes and feed were analyzed on the residual stress field and the magnitude and depth of the maximum compressive residual stress in AISI 1045 steel specimens. The model validation was performed compar...
Article
Experiments for cooling curve analysis of laboratory-scale quenched probes produce a wetting front that advances at a finite velocity along the longitudinal axis of the probe as cooling progresses. The wetting front velocity depends on probe material and geometry as well as the type of quenchant, its temperature, and agitation. Because of the wetti...