2020 Technical Division Student Poster Contest: LMD 2020 Technical Division Graduate 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

SPG-29: Comparing Traditional and Designer Alloy Feedstock Powders for Additive Manufacturing: Jack Grubbs¹; Kyle Tsaknopoulos¹; Danielle Cote¹; ¹Worcester Polytechnic Institute
    Metal powder-based additive manufacturing (AM) techniques often rely on traditional alloys to create a processed part. However, processing and performance capabilities are not optimized with these traditional powders, prompting a need for designer feedstock material. Considering variations in powder morphology and composition, research was conducted to compare both traditional and designer feedstock powders for AM applications. Ideal feedstock powder for AM can be characterized by narrow particle size-shape distributions, as well as superior powder properties. Powder properties are directly connected to internal microstructure; thus, a precisely controlled microstructure is necessary for optimal powder performance. A powder's microstructure can be manipulated by thermal treatments, therefore both heat-treated and as-received powders were evaluated. Powder morphology was characterized using a synchronous laser diffraction and dynamic image particle analyzer, and the microstructure was analyzed using scanning electron microscopy, energy dispersive x-ray spectroscopy, and nanoindentation. Analysis was guided through computational thermodynamic and kinetic models.

SPG-30: Effect of Mechanical Milling and Cryomilling on Synthesis of CNT Reinforced 6082 Al Matrix Nanocomposites: Rajat Gupta¹; Yagnesh Shadangi¹; Kausik Chattopadhyay¹; Anil Chaubey²; Nilay Mukhopadhyay¹; ¹Indian Institute of Technology IIT-BHU; ²AMT Department, CSIR- IMMT
    The influence of mechanical milling (MM) and cryomilling (CM) on the structure, morphology, phase composition, thermal stability and mechanical properties of multi-walled carbon nanotubes (MWCNTs) reinforced AA 6082 alloys nanocomposite powders has been studied through XRD, TEM, SEM-EDS, Raman spectroscopy and indentation techniques. The MM leads to uniform distribution of CNT in the matrix and cryomilling further reduces its agglomeration and helps in embedding the CNTs into the aluminum matrix composites (AMCs) by effectively shearing the nanotubes. The broadening of diffraction peaks due to milling suggest the enhancement of lattice strain and reduction in the crystallite size. Further, attempts were made to consolidate the MM+CM AMCs by hot pressing followed by hot extrusion. The mechanical properties of AMCs were evaluated through indentation and compressive testing techniques up to 300蚓. It has been observed that cyromilling helps in overcoming the problem associated with agglomeration of Al-CNT composites with enhanced mechanical properties.

SPG-31: Effect of Processing Parameters on Additively Manufactured WE43 Mg Alloy: Leila Sorkhi¹; Joshua Hammell¹; Grant Crawford¹; ¹South Dakota School of Mines and Technology
    Magnesium (Mg) alloys are of interest for use in biodegradable load-bearing bone implants due to their excellent biocompatibility, comparable mechanical properties to natural bone, and unique ability to naturally degrade in the physiological environment. Over past decade, additive manufacturing of Mg alloys has gained increased interest for the potential to fabricate complex geometries for extreme light-weighting or improved functionality. Nevertheless, there is still a significant need to establish the influence of various processing parameters on the microstructure and mechanical behavior of additively manufactured Mg alloys. In this study, the effect of processing parameters (i.e. laser power and time interval) on the microstructure, mechanical, and degradation behavior of WE43 Mg alloy specimens fabricated by laser powder directed energy deposition (LPDED) was investigated. Microstructure characterization of the additively manufactured samples was conducted using optical microscopy and scanning electron microscopy. Mechanical behavior of the samples was investigated using microhardness and uniaxial tensile testing.

SPG-32: Effects of Mg and Si Additions to Novel Al-Ce base Alloys for Aerospace Applications: Manny de Jesus-Lopez¹; Ramon Padin-Monroig¹; Oscar Suarez¹; ¹University of Puerto Rico, Mayaguez
    Previous studies comment on how amounts of Mg and Si produce metastable phases within Al-Ce base alloys. The phases present in said alloys were Al₁₁Ce₃, Mg₂Si, and τ₁-AlCeSi, which affect alloy mechanical properties and thermal response. Research results revealed that adding Mg and Si affected directly the melting temperature range, microstructure, micro-hardness, and density. When adding Mg and Si at a 1:2 and 1:5 ratios to eutectic Al-Ce alloys, the melting temperature range lies between 563 °C and 618 °C, respectively. Furthermore, by adding either Mg, Si, or both the micro-hardness values increased from 500 MPa to over 1 GPa as the alloy density decreased from 2.85 and neared 2.7 g/cm³. Thus, Al-Ce-based alloys can be tailored for high temperature applications while maintaining good weight-to-strength ratios. The on-going work centers on expanding the study of other chemical compositions and performing heat treatments seeking to control the presence of metastable phases.

SPG-33: Enhancement of Mechanical Properties by Large Strain Extrusion Machining of Aluminum Alloy: Vagish Mishra¹; Karthik Palaniappan¹; Balkrishna Rao¹; Murthy H.¹; ¹Indian Institute of Technology Madras
    Mechanical properties of Al6061 alloy, a light metal alloy, can be enhanced by microstructure evolution by many mechanical processes. In current effort, large strain extrusion machining (LSEM) with different chip compression-ratio (3.7, 2, 1, 0.7, and 0.5) was used to control final foil-thickness and microstructure. Low-speed-machining was performed to reduce heat generation in primary shear zone and interface between chip-tool and to avoid re-crystallization in foil. Significant decrease in grains size (~15痠) of foil compared to bulk (~165痠) while hardness increased by nearly 70% were found. Orthogonal plain-strain machining and LSEM results in nearly same grains-size decrement and hardness enhancement with LSEM affording control of geometry of bulk form. There was no significant increment in hardness with further decrement in chip compression ratio. Fine-grained foils were found stronger and brittle in nature which can be used with ductile matrix in the form of powder or in the form of foils.

SPG-34: Impact of Cold Metal Transfer Arc Mode on Additive Manufactured Aluminum Alloy Multilayered Structure: Mohammad Sharif Poor¹; Nicholas Sheldon¹; Yeonjin Baek¹; Tae-Kyu Lee¹; ¹Portland State university
    Cold Metal Transfer (CMT) provides low heat input which result in minimized heat affected zone at the layer interface. Combined with a 6-axis robot arm system, it can produce stable and high deposition rate structures with single or multi-material layers. In this study, additive manufactured structures with 5000 aluminum alloy series using CMT are subjected to mechanical testing. 15cm x 10cm x 0.4cm Plate structures are build-up with combination of two different CMT arc modes with variation in heat input. The arc mode variation provided with different grain size distribution, which can affect mechanical properties. For using the residual stress after build-up, Ultrasonic Impact Treatment (UIT) process was applied to the sample surface to see the effect on mechanical stability. Tensile test and Charpy impact test were performed with Electron Backscattered Diffraction (EBSD) analysis to see the evolution of local strain and stress at the layer interface per arc mode.