2017 Technical Division Student Poster Competition: Structural Materials Division (SMD) Graduate 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

SPG-39: A Novel Approach for Forming Ductile and Strong Cu-to-Cu Interconnection Using Ga-based Pastes: Che-yu Yeh1; Shih-kang Lin1; 1National Cheng Kung University
    Direct Cu-to-Cu interconnection is an important process for application in three-dimensional integrated circuit (3D IC) and wide band gap (WBG) device in electronic packaging industry. Cu-to-Cu interconnection can be made using thermo-compression, micro-bumping, or sintering with nano/submicron particles. However, thermo-compression requires high temperature and is time consuming, which makes it an expensive process. Micro-bumping is considered a cheap and fast process, but brittle and electrical resistant intermetallic compounds (IMCs) would form at the joints, which raises significant reliability concerns. Sintering with nano/submicron particles forms porous joints with poor thermal stability, which again does not meet the requirements in electronic industry. In this presentation, we demonstrate new materials and new processes for fabricating ductile and strong Cu-to-Cu joints using Ga-based pastes. This approach opens a door for a new concept for Cu-to-Cu interconnection, which can be applied for applications on 3D IC and WBG devices.

SPG-40: A Preliminary Study on the High Energy Ball Milling and Spark Plasma Sintering of Fe-9Cr Alloy: Arnab Kundu1; 1University of Idaho
    Iron powder and chromium powder batches are milled together for different durations (2, 5, 8, 10, 12, 15 and 20 h). Various powder characteristics such as crystallite size, lattice strain and powder size were evaluated. Consolidation was mainly focused on the 10 h milled powder which was consolidated via spark plasma sintering at 850, 950 and 1050 oC for different dwell times. The effects of sintering parameters on densification, hardness and grain size are also evaluated. The grain size increased with increasing sintering temperature and dwell time. This work is expected to lead to the basic understanding of a simple Fe-9Cr system and will be later expanded to more complex oxide dispersion strengthened alloy systems keeping the Fe-9Cr type matrix the same. The work is supported by the Laboratory Directed R&D funding provided by the Idaho National Laboratory via the Center for Advanced Energy Studies.

SPG-41: Corrosion Behavior of Alloy 800H in Supercritical CO2: Lucas Teeter1; Benjamin Adam1; Jacob Mahaffey2; Mark Anderson2; Julie Tucker1; 1Oregon State University; 2University of Wisconsin Madison
    The corrosion behavior of high iron-nickel-chromium 800H alloy was investigated in supercritical CO2 (sCO2) in order to simulate conditions that would exist in indirect sCO2 power cycles. The exposure tests were carried out using research grade CO2. The experimental pressures for the experiments was 20 MPa with temperature conditions of 650 and 750 C. Samples were incrementally exposed up to 1000 h in order to demonstrate the corrosion kinetic behavior of the alloys. The corrosion kinetics of each exposure set was determined by mass gain measurements. The surface morphology and the composition of the corrosion product layers were analyzed using surface analysis techniques including X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Preliminary results for the 800H indicate that under the environmental conditions at 750 C the alloy forms a two layer surface oxide and some internal oxidation.

SPG-42: Evaluation of Interfacial Layer of Friction Stir Welded Joint of AA6022-T4 and DP600 Sheets: Tianhao Wang1; Harpreet Sidhar1; Rajiv Mishra1; Piyush Upadhyay2; Yuri Hovanski2; Glenn Grant2; Blair Carlson3; 1University of North Texas; 2Pacific Northwest National Lab; 3General Motors
    Lap welding of AA6022-T4 alloy sheets with 1.0 mm thickness and DP600 steel sheets with 1.2 mm thickness was performed by friction stir welding (FSW). During the welding process, aluminum sheet was placed on the top of steel sheet, and welding tool penetrated upper lap material to touch the lower lap material. High tool rotation rate (2000-2500 rpm) and traverse speed (1000-1500 mm/min) was used to control the thickness of intermetallic layer. The peak failure load of optimized lap welds can reach 95% of that of weaker base material, which is AA6022-T4 aluminum alloy sheet. Control of the intermetallic compound (IMC) layer thickness between aluminum and steel sheets during welding is critical for integrity of the joint. Relationships between welding parameters, IMC layer thickness and the resultant mechanical properties were evaluated in this study.

SPG-43: Evaluation on Oxidation Behavior of Nanocrystalline CrN Deposited Zr-4 Alloys at High Temperature: Cheng-Wei Shen1; Fan-Yi Ouyang1; Kai-Ping Chang1; 1National Tsing Hua University
    In this study ,we deposited chromium nitride(CrN) thin film on Zircaloy-4(Zr-4) substrates by using unbalanced magnetron sputtering(UBMS) system to investigate the corrosion resistance of fuel cladding at high temperature, ranging from 400℃-600℃ in steam environment for 2,4 and 6 days. The results show that the weight gain of CrN-coated samples is about 90% less than that of uncoated substrates, suggesting that introducing a CrN thin film can effectively improve the corrosion resistance of Zr-4 at high-temperature steam environment.

SPG-44: Formation of Large-sized and Ductile CuZr-based Bulk Metallic Glass Composite: Wenli Song1; Yuan Wu1; Jie Zhou1; Di Cao1; Fei Zhang1; Qing Du1; Hui Wang1; Xiongjun Liu1; Zhaoping Lu1; 1University of Science and Technology Beijing
    Bulk metallic glass (BMG) composites consisting of transformable reinforcing phases exhibited promising properties under tension, however, the limited maximum size of such glassy composites restricts their practical engineering applications. In our work, CuZr-based BMG composite with nearly 1 centimeter and a significant tensile strain of 7.01.0% was successfully developed. Detailed analysis of glass formation kinetics and phase competition revealed that additions of Al and Ag greatly improved the glass-forming ability of amorphous matrix and stabilized the B2 phase in CuZr-based BMG composites. Proper addition of Sn induced formation of Zr5Sn3 which acted as heterogeneous nucleation sites for B2 due to the low planar disregistry between them, thus resulting in formation of desirable composite microstructure consisting of B2 with appropriate sizes and distribution. Our findings have great implications in fabricating large-sized BMG composites. The inoculation strategy is applicable to all the BMG systems for achieving good tensile ductility and strong work-hardening.

SPG-45: Frequency, Hold Time and Overload Effects on Crack Growth Rates in Alloy 617 at 800C in Air: Dylan Addison1; Jamie Kruzic2; 1Oregon State University; 2University of New South Wales
    Understanding the elevated temperature crack growth mechanisms for Alloy 617 is an important part of qualifying the material for safe use in heat exchangers and steam generators in next generation nuclear power plants. At 800C, there is a potential competition between transgranular cracking, the effect of stress assisted grain boundary oxidation (SAGBO), and creep cavitation depending on the test conditions. To examine the range of potential behavior, experiments using compact tension specimens were performed under cyclic fatigue conditions, creep-fatigue conditions using cyclic loading with hold times, and cyclic fatigue interrupted by blocks of overloads. Fracture surfaces and crack profiles were compared to elucidate the crack growth mechanisms. It was found that both intergranular creep damage and transgranular fatigue damage mechanisms compete to create a complex response at the crack tip. It is expected that these results will aid in multi-scale model development for creep-fatigue crack growth in Alloy 617.

SPG-46: High Strain Rate Deformation and Work Hardening in Ti-1Al-4V Alloy: Zachary Kloenne1; Gopal Viswanathan1; Matthew Thomas2; Michael Lorreto3; Hamish Fraser1; 1Center for Accelerated Maturation of Materials; 2TIMET; 3University of Birmingham
    Excellent machinability combined with increased ballistic impact performance make Ti-1Al-4V (Ti-407) an ideal candidate to replace Ti-6Al-4V or Ti-3Al-2.5V alloys in many applications. Ti-407 achieves these properties through a combination of high ductility and moderate strength. Specimens with the above compositions were tested in tensile and compression at high strain rates (1000 s-1) using a Split-Hopkinson pressure bar. Ti-407 experienced high degrees of strain at very high strain rates. The improved high strain rate properties appear to involve a quite remarkable work hardening behavior. In this investigation, operative mechanisms in the specimens were studied to better understand the improved properties. Particular attention was paid to the deformation behavior of the beta phase. Scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD) were used to analyze the microstructure of the deformed and un-deformed specimens. Transmission electron microscopy (TEM) was used to examine the deformation behavior and the nature of the substructure.

SPG-47: Medium-Range Correlations and Its Impact on Properties in Al-RE Marginal Glass Forming Alloys: Mustafacan Kutsal1; Eren Kalay1; 1Middle East Technical University
    Marginal glass forming alloys have known to devitrify with an extraordinary number density of nanocrystals, values up to 10^23-10^25 m-3, numbers that are several orders of magnitude higher than theoretical predictions. To unveil this behavior, glassy and molten states of Al-RE binary metallic glasses were investigated using experimental approaches such as DSC, synchrotron radiation, TEM, fluctuation microscopy (FEM) and 3DAP as well as with computational methods such as RMC and MD modelling. Experimental and modelling efforts have shown the presence of medium-range ordered prenucleation clusters of ~1-2 nm. Devitrification mechanisms these glasses were also found to be affected by amorphization precursor and alloy constitution. SRO was found to have negligible effect on phase selection hierarchy, yet the extent of MRO has a dominant effect on chemistry and morphology selection of nanocrystals. The structural heterogeneities in molten and quenched states of Al-RE alloys will be presented regarding experimental and computational findings.

SPG-48: Non-destructive 3D Characterization of the Microstructural Evolution of Additively Manufactured Materials: Tugce Ozturk1; David Menasche2; Robert Suter1; Anthony Rollett1; 1Carnegie Mellon University; 2Hamiltonian Group LLC
    Additive manufacturing is increasingly being implemented to structural metallic components, yet especially for metals such as Ti alloys that result in heterogeneous microstructures even with conventional thermo-mechanical processes, the microstructural evolution is still work in progress. For the non-destructive characterization of additively manufactured Ti alloys, high-energy X-ray diffraction microscopy (HEDM) and high-energy computed tomography techniques are utilized at Argonne National Laboratory. Samples of varying AM processing parameters (high velocity-low power vs. low velocity-high power e-beam setting), varying heat treatments (as received, stress relieved and annealed samples), and varying alloy compositions (compositionally gradient near beta Ti-Fe as a new AM alloy candidates) are characterized with near-field, far-field and tomography modalities towards investigation of microstructural evolution, which provide grain morphology, lattice strain and grain orientation information for distinct materials.

SPG-49: Optimization of the Diffusion Bonding Process for Al 6063 Alloy: Sıla Atabay1; Arcan Dericioglu1; 1Middle East Technical University
    Diffusion bonding (DB) is an effective solid state joining process for both similar and dissimilar materials. In this process bonding is achieved by holding the metals under pressure at a temperature ranging 0.5-0.8 of the melting point of the used metal. Quality of the joints is dependent on the time, temperature and pressure of the process as well as the prior surface preparation and chemical composition of the interface. Optimum DB process parameters for Al6063 alloy were determined in this study. Change in the mechanical properties of the bonds and base metal with the heat treatment cycles during the bonding was examined via tensile testing and hardness measurements. Combined microstructural characterization and XRD measurements were conducted to investigate the effect of precipitation and grain growth on the mechanical properties. Fracture surfaces of the mechanically tested joints were also observed.

SPG-50: Nanocrystallization in Cu-Zr-Al-Sm Metallic Glasses: Fatih Sıkan1; İlkay Kalay2; Yunus Eren Kalay1; 1Middle East Technical University; 2Cankaya University
    Micro-alloying of RE (Rare-earth) elements into Cu-Zr-Al bulk metallic glass is a promising technique to increase the glass forming ability. On the other hand, its effect on the amorphous structure and corresponding crystallization kinetics has not been well studied. In this respect, we have investigated the as-quenched amorphous structure and consecutive crystallization behavior of Sm micro-alloyed Cu-Zr-Al based bulk metallic glasses. Ingots of (Zr50Cu40Al10)100-xSmx (0 < x < 4, at. %) were produced by arc-melting and subsequently melt-spun to synthesis metallic glasses in the form of ribbons. Devitrification paths of the glassy specimens were investigated using DSC. Crystallization activation energies and thermal stability of the glassy phase were investigated with respect to at. Sm %. Sm was found to trigger nanocrystallization of Cu2Sm phase. The as-solidified and partially crystallized specimens were characterized by a combined study of TEM and XRD.

SPG-51: The Activity of Pyramidal Slip Systems in a Mg-3Al-1Zn Alloy during High Cycle Fatigue: Li Tan1; Xiyan Zhang1; Guangjie Huang1; Qing Liu1; 1Chongqing University
    <c + a> pyramidal dislocations of commercial rolled Mg-3Al-1Zn (AZ31) magnesium alloy during high cycle mechanical fatigue testing with the various stress amplitude levels were investigated at room temperature. The result shows that stress amplitude has significant influence on the activation of fatigue damage mechanisms. When the stress amplitude is 60MPa, which is close to the fatigue strength, only basal dislocations are observed, no <c + a> dislocations are observed in samples. When the stress amplitude increases to 110MPa, which is higher than the fatigue strength, few {10-12} tensile twins ,{10-11}-{10-12} double twins and lots of <c + a> pyramidal dislocations were generated in fatigued samples.

SPG-52: The Effect of Plasma Mark on Steel Structural Integrity: Sujeily Soto1; Jeffrey Rossin1; Michael Kesler; Edward George2; Steve Duke3; Michele Manuel; 1University of Florida; 2E&S Consulting, Inc; 3Florida Department of Transportation
    During steel bridge fabrication, dies and paint are typically utilized to mark the material to identify parts and provide instruction during construction. The possibility of using plasma scribing can lead to the automation of the marking process. One of the biggest advantage of using plasma marking is the ease of integration into existing manufacturing processes, as the technology is already in use for sectioning plates at steel fabrication facilities. To safely implement this technique, the mechanical integrity of the parts cannot be affected. Weathering steel 50W plates were marked with plasma using different parameters. The heat affected zone (HAZ) depth made by the plasma marking was measured. These measurements are correlated with the plasma marking parameters, i.e. the power and speed of the marking, illustrating the relationship between microstructural changes and the fatigue properties of the steel.

SPG-53: TRIP Titanium Alloy Design: Fan Meng1; Jia-Yi Yan2; Wei Xiong3; Gregory Olson1; 1Northwestern University; 2KTH Royal Institute of Technology; 3University of Pittsburgh
    A novel near-α TRIP titanium alloy Ti-8111Fe for structural applications combing Ti-64’s strength and Ti-5111’s fracture toughness was computationally designed. Solid solution strengthening and transformation induced plasticity (TRIP) toughening are main strategies applied in this design. In order to maximize the TRIP toughening effects, the characteristic MSσ defining the β phase stability at the stress states crack tip (ct) was set to application temperature (room temperature in this case) using mechanistic models on the thermodynamics and kinetics of martensitic transformation in titanium alloys. On the other hand, desired positive martensitic transformation dilatation was calculated from a room temperature molar volume database developed for β, α’and α” phases. Predicted phase compositions and phase fractions of Ti-8111Fe annealed at 865 oC were experimentally validated.