Pan American Materials Congress: Materials for Transportation and Lightweighting: Processing-Structure-Property Relationships I
Sponsored by: Third Pan American Materials Congress Organizing Committee
Program Organizers: Mary Wells, University of Waterloo; Rafael Colás, Universidad Autónoma de Nuevo León; Fernand Marquis, San Diego State University; Ramalinga Viswanathan Mangalaraja, University of Concepcion; Marta Lopez, University of Concepcion; Elvi Dalgaard, Pratt & Whitney Canada; Patricia Zambrano, Universidad Autonoma de Nuevo Leon

Tuesday 10:20 AM
February 28, 2017
Room: Mission Hills
Location: Marriott Marquis Hotel

Session Chair: Patricia del Carmen Zambrano Robledo, Universidad Autónoma de Nuevo León/Investigación

10:20 AM  
Mechanical and Microstructural Evaluation of New Superalloys, an Actual Review: Octavio Covarrubias1; 1Exova
     Nickel base alloys are key materials needed to design and assembly components to be used in jet-engines used in actual aircraft. The development of new superalloys is critical in order to improve the performance of new propulsion systems. In order to determine the characteristics of new nickel-base alloys, mechanical testing and metallurgical evaluation are essential activities required to validate the required properties of these materials.In this job is presented an actual review of latest nickel-base superalloys developed since beginning of 2000 decade and what is their impact in the design of new engine programs used by the most important manufacturers of airplanes worldwide.

11:00 AM  Cancelled
Phase Transformations in Continuous Heating and Aging Heat Treatments in Ti-Nb-Fe Alloys: Fernando da Costa1; Mariana de Mello1; Camilo Salvador1; Rubens Caram1; 1University of Campinas
    Beta metastable Ti-30Nb and Ti-30Nb-1Fe alloys were subjected to different aging heat treatments. Several temperatures and heating rates were employed to determine their influence on α phase precipitation. Alloys were characterized by means of differential scanning calorimetry, X-ray diffraction, scanning and transmission electron microscopy. Mechanical properties were evaluated, such as Vickers hardness and elastic modulus, and tensile tests were also performed. The results indicate that the addition of Fe reduces the alpha phase precipitation and  dissolution temperatures, although omega phase was still detected in Ti-30Nb-1Fe aged at 400oC. The addition of Fe caused refinement of alpha phase precipitates, probably due to the higher diffusion coefficient of Fe. As for the influence of the heating rate, 2 and 30oC/min did not cause significant microstructural changes. Finally, alpha phase refinement in Ti-30Nb alloy was favored by aging at 550oC, at a heating rate of 600 oC/min.

11:20 AM  
Study of Phase Transformations and Decomposition of Martensite in FV535 High Cr Martensitic Steel: Lizangela Guerra1; Patricia Zambrano1; Armando Salinas2; Edgar Garcia1; 1Universidad Autonoma de Nuevo Leon, Facultad de Ingenieria Mecanica y Electrica; 2Centro de Investigacion y de Estudios Avanzados del IPN Unidad Saltillo
    FV535 is a 12Cr-Mo-VNbWCo steel used in gas turbine engineering, aircraft and aerospace industries and nuclear reactors components . The phase transformations that occur in this type of steel were analyzed by differential scanning calorimetry and XRD at high temperature. The decomposition process of the martensite has been divided in six different stages occurring at different temperatures range and which can vary depending on the steel composition and microstructure, these stages were studied by DSC, the precipitation that occurs in the decomposition of martensite was analyzed by DSC and electron microscopy.

11:40 AM  
Fatigue Behavior of Plasma Scribed HSLA Steels: Jeffrey Rossin1; Michael Kesler1; Edward George2; Steve Duke3; Michele Manuel1; 1University of Florida; 2E&S Consulting, Inc.; 3Florida Department of Transportation
    High Strength Low Alloy (HSLA) weathering steels are commonly used for fracture critical members in bridges used for transportation. Recently plasma scribing has shown the potential to mark steels in an automated fashion, however, state Departments of Transportation (DOTs) often do not allow these steels marked by this method due to concerns over the potential degradation in mechanical properties, specifically fatigue strength. Previous data, though limited in sample size and experimental parameter space, shows that plasma scribing has a minimal effect on fatigue performance. This study has expanded the range of parameters to more aggressive values. Data will be presented under various scribing parameters to understand the correlation between marking settings (amperage and speed of marking) and microstructure with mechanical properties such as tensile strength and fatigue performance. Insights in to failure prevention will be presented. This project was supported by the Florida DOT under the contract number BDV31 977-50.

12:00 PM  Cancelled
FeCrAl-steels as Candidates for Structural Material in CSP Systems with Lead-bismuth Eutectic as a Heat Transport Fluid: Miroslav Popovic1; Alan Bolind1; Peter Hosemann1; 1University of California, Berkeley
    Heavy liquid metals have an important application in energy transport and storage, due to their good thermal properties. Lead-Bismuth Eutectic (LBE) is used as a heat transport fluid in concentrated solar power (CSP) systems due to its thermal properties and low reactivity. In order to improve thermal efficiency, temperatures should rise up to 800C. However, the corrosion effects on structural materials at high temperatures is a key limiting factor of LBE use. The main challenge is to find proper structural materials well-resisting to the corrosion. In this work, the results of our systematic materials survey in liquid LBE under oxygen-controlled conditions are presented, along with static corrosion test design. Three different FeCrAl-steels, as structural material candidates, have been exposed to liquid LBE at high temperatures in oxygen-controlled atmosphere. Post-corrosion characterization by micro-structural analysis methods (SEM/EDS, X-ray diffraction, Raman spectroscopy) enables a comparison of anti-corrosive properties of tested steels.

12:20 PM  
Observations and Analyses of Tribochemical Reactions in Lightweight Boron Carbide (B4C) Impacted at High-Velocity: Jerry LaSalvia1; Scott Walck1; Kristopher Behler1; Brady Aydelotte1; Brian Schuster1; 1U.S. Army Research Laboratory
    Extending several millimeters from the impact site, millimeter long, micrometer wide features consisting of micron and nano-sized particles were observed in B4C impacted at high-velocity with a WC-6Co sphere. Morphologies of Al2O3 inclusions within these features suggest the presence of a high temperature melt. Furthermore, oxidation of B4C during the ballistic event appears plausible because Raman spectra from these features were similar to those from unintentionally oxidized B4C annealed at high temperatures. Energy-dispersive spectroscopy confirmed the presence of O in these features. These results, along with results from other experiments, provides evidence for melt formation via tribochemical reactions. During impact, WC-6Co fragments slide across the B4C surface resulting in frictional heating. Oxidation reactions are initiated which lead to melt formation. The resulting melt penetrates into cracks, resulting in the observed features. This is supported by an analytical model and TEM analyses. Experimental procedures, results, and analyses are presented.