2017 Technical Division Student Poster Competition: Light Metals Division (LMD) Undergraduate Students
Sponsored by: TMS Extraction and Processing Division, TMS Functional Materials Division, TMS Light Metals Division, TMS Materials Processing and Manufacturing Division, TMS Structural Materials Division
Program Organizers: TMS Administration

Monday 5:00 PM
February 27, 2017
Room: Hall B1
Location: San Diego Convention Ctr

SPU-6: Fabrication of Novel Aluminum Welding Fillers Reinforced with NbB2 Nanoparticles: Lourdes Cruz1; Andres Calle1; Victoria Nadal1; 1University of Puerto Rico at Mayaguez
    Aluminum welds satisfy requirements of strong joints of parts adding minimal weight, as demanded in many structures. However, the performance of these welds at high temperatures is unsatisfactory showing crack sensitivity. Aluminum fillers containing niobium diboride (NbB2) nanoparticles for TIG welding can improve the weld quality and increase its high-temperature service capacity. Our ongoing research centers on the study of the thermal expansion coefficient of the reinforced filler along with an analysis of the melting behavior upon welding on a commonly-used base material. The thermal expansion coefficient of the filler containing nanoparticles was compared to a commercial 5356 filler through a full factorial design experiment. The hardness and porosity of these materials were also compared through analysis of variance.

SPU-7: Influence of Mn on Mechanical Properties in Aluminum Alloy 6082: Aedan Callaghan1; Jasmine Majdpour1; Lucas Alexander1; Amir Farkoosh1; Mihriban Pekguleryuz1; 1Department of Materials Engineering, McGill University
    This work deals with the effect varying manganese content has on dispersoid formation in aluminum alloy 6082, and the corresponding changes to grain size and mechanical properties. Dispersoids aid extrusion alloys in maintaining their deformed microstructure and corresponding mechanical properties. Increasing Mn from 0.5 wt% to 1.0 wt% resulted in a higher concentration of dispersoids. Hardness tests demonstrated an increased strength in 1% Mn alloy throughout recrystallization, as dispersoids restricted grain boundary mobility and maintained smaller grains. Compression tests at extrusion temperature revealed higher flow stresses in the 1% Mn and that dislocation motion was restricted by the increase in dispersoids through Orowan strengthening mechanisms. Tensile tests revealed slightly lower ductility in the 1% Mn alloy due to an increase of primary intermetallics. Overall an increase in Mn from 0.5% to 1% will produce a more dispersoid rich alloy that better resists recrystallization and grain growth.

SPU-8: Phase Stability of bcc MgSc Alloys via Cluster Expansion and Monte Carlo Methods: Adam Shaw1; Gregory Pomrehn2; Aurora Pribram-Jones3; Patrick Conway4; Michael Ferry4; Kevin Laws4; Lori Bassman1; 1Harvey Mudd College; 2The Boeing Company; 3Lawrence Livermore National Lab; 4University of New South Wales
    The MgSc disordered bcc lattice has the potential for light weight, high strength applications, but is only stable far above room temperature. It is thought that the addition of ternary or quaternary components to the binary system could stabilize this phase at accessible lower temperatures. However, the search space for possible ternary candidates is too large to fully explore experimentally. Thus, to guide the physical alloy development, computational methods are applied to determine the phase stability of the MgSc binary and associated ternaries. A lattice cluster expansion model is developed based on density functional calculations, and finite temperature thermodynamic behavior is computed from Monte Carlo simulations. The method elucidates ternary elements that best lower the stable temperature regimes of the bcc phase.

SPU-9: Thermodynamic Assessment and Microstructural Analysis of AA 6082 with Increased Addition of Manganese: Lucas Alexander1; Jasmine Majdpour1; Aedan Callaghan1; Amir Farkoosh1; Mihriban Pekguleryuz1; 1McGill University
    This experiment investigated the effects of Mn additions of 0.5 wt% and 1 wt% on phase formation and recrystallization in an Al-Mg-Si alloy, AA6082. Mn addition controls recrystallization and grain growth in hot deformed Al alloys through the formation of fine dispersoids, which hinder the grain boundary mobility by exerting Zener pinning pressure. Thermodynamic calculations, equilibrium and non-equilibrium, were conducted using FactSage™ software to determine the phases formed and the optimum amount of the dispersoids in this alloy system.  Calculations based on increasing manganese contents revealed a positive correlation between Mn and dispersoids formation up to ~1 wt%. Mn above 1 wt% can only increase the amount of the primary α-Al(Fe,Mn,Cr)Si intermetallics. The calculations were corroborated with SEM and TEM analyses of the as-cast and extruded alloys. The higher amount of the dispersoids can lead to a finer microstructure, better formability and enhanced mechanical properties of the final products.