2020 Technical Division Student Poster Contest: SMD 2020 Technical Division Undergraduate Student Poster Contest
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 5:30 PM
February 24, 2020
Room: Sails Pavilion
Location: San Diego Convention Ctr
SPU-17: Computational Indicators of Ductility in Compositionally-complex B2 Alloys: Emily Hwang1; Emma Cuddy1; Julianne Lin1; Aurora Pribram-Jones2; Jonas Kaufman3; Kevin Laws4; Lori Bassman1; 1Harvey Mudd College; 2University of California, Davis; 3University of California, Santa Barbara; 4University of New South Wales
Alloy compounds of the B2 crystal structure are known to exhibit limited ductility due to their structural ordering and covalent bonding nature. However, some previously established B2 binary alloys and recently developed B2-structured precious metal-rare earth multicomponent alloys have demonstrated unusually high ductility. Using density functional theory, this study examines a method to predict ductility in binary B2 alloys and adapts this method for high entropy alloys. Ductility is governed by slip deformations on favored planes, so the relative energetic favorability of stacking faults and antiphase boundaries on different slip planes forms a metric to indicate ductility. The atomic ordering of the multicomponent alloys is determined through refinement of experimental XRD data, and any disorder is represented with special quasirandom structures. Special attention is paid to lanthanide alloys, which are often mischaracterized by exchange-correlation functionals due to self-interaction errors with the f-electrons.
SPU-18: Design of a Novel Complex Concentrated Alloy for Orthopedic Implant Applications: Jose Dominic1; Gopinath Perumal1; Harpreet Grewal1; Geetha Manivasagam2; Sundeep Mukherjee3; Harpreet Arora1; 1Shiv Nadar University; 2Vellore Institute of Technology; 3University of North Texas
Prudent materials selection is vital in the success of a bioimplant. Biocompatibility, degradation in bio-media, and osteopenia are all important considerations in the design of biomaterials fit for function. By combining the existing alloy design strategies based on bond order and d-orbital electron theory with additional considerations such as cytotoxicity, we designed a complex concentrated alloy. The issue of microstructural heterogeneity was addressed by severe plastic deformation processing. The designed alloy MoNbTaTiZr exhibits superior biocorrosion and mechanical property profile for use in orthopedic implant applications as compared to available bio-inert metallic alternatives such as surgical stainless steel (SS316L) and Titanium (Ti-6Al-4V) alloys. By exploring the design space of high entropy alloys and addressing primary concern of elemental segregation, this work provides a new avenue for the facile design and development of similar alloys for structural implant applications.
SPU-19: Elimination of the Sigma Phase in a Compositionally Complex Fe-Cr-based System: Stephanie Blankley1; Holly Frank1; Jackson Baker1; Natalie Krieger1; Douglas Raigosa1; Patrick Conway2; Kevin Laws2; Lori Bassman1; 1Harvey Mudd College; 2University of New South Wales
The Fe-Cr parent system serves as a basis for ferritic steels that exhibit high corrosion resistance. At temperatures in the range of 500 to 850 °C, these alloys have a tendency to precipitate the brittle sigma phase, limiting their processability and application. Inspired by high entropy alloy concepts, this work has successfully inhibited the formation of sigma with the addition of Mn in combination with other alloying elements. The elimination of sigma has been confirmed experimentally by scanning electron microscopy and x-ray diffraction analyses over a range of alloy compositions and heat treatment conditions. First principles modelling has shown that the interplay between alloying elements disrupts the complicated atomic packing structure within the sigma phase, diminishing its stability.
Cancelled
SPU-20: Facture Toughness Determination Using Single Edge Notch Wire (SENW) Specimen: Hrushikesh Sahasrabuddhe1; A. K. Mishra1; Kevin Jacob1; B.N Jaya1; 1IIT-Bombay, Mumbai, India
Single edge notch wire (SENW) specimens are used for fracture toughness testing of cylindrical wires, e.g.: cold drawn pearlitic steel wires used in suspension bridge cables and tire cords. The fracture toughness testing requires an appropriate geometric factor - f(a/d), as input. Extended finite element calculations are carried out in the present study to compute f(a/d) for different aspect ratios (h/d) of the wire, assuming homogeneous specimen. These results vary significantly from those reported in the literature. This f(a/d) is experimentally confirmed using Poly (methyl methacrylate) - PMMA, a brittle polymer with a known KIC, where assumptions of homogeneity and isotropy hold true. SENW specimens are then employed to determine KIC of steel wires before and after annealing conditions to quantify the enhancement in toughness. Results will be compared to the values reported in the literature, and future scope of this geometry for other applications will be discussed.
SPU-21: Strengthening Mechanisms of Ultra-strong Fe-Zr Solid Solution Alloys: Sidharth Krishnamoorthi1; Ruizhe Su1; Yifan Zhang1; Xinghang Zhang1; 1Purdue University
Nanocrystalline metals have been widely explored due to their unique mechanical behaviors. Grain boundaries are known to be barriers to the transmission of dislocations and hence grain refinement can lead to improved mechanical strength. In this study, we show that the hardness of Fe can be significantly increased by using Zr to form supersaturated solid solution alloys. Nanoindentation tests show that the hardness of Fe-Zr solution alloy films can exceed 9 GPa with an average grain size of 20 nm. Transmission electron microscopy studies show that the grain size of Fe-Zr decreases with increasing Zr content. The influence of microstructure on mechanical properties of Fe-Zr films is discussed. Our findings could provide general implications on the design of high-strength Fe alloys.