Characterization of Minerals, Metals and Materials: Characterization of Mechanical Properties I
Sponsored by: TMS Extraction and Processing Division, TMS: Materials Characterization Committee
Program Organizers: Jian Li, CanmetMATERIALS; Mingming Zhang, Baowu Ouyeel Co. Ltd; Bowen Li, Michigan Technological University; Sergio Monteiro, Instituto Militar de Engenharia; Shadia Ikhmayies; Yunus Kalay, Middle East Technical University; Jiann-Yang Hwang, Michigan Technological University; Juan Escobedo-Diaz, University of New South Wales; John Carpenter, Los Alamos National Laboratory; Andrew Brown, Devcom Arl Army Research Office

Tuesday 2:00 PM
February 25, 2020
Room: Theater A-5
Location: San Diego Convention Ctr

Session Chair: Rajiv Soman, Eurofins EAG Materials Science LLC; Donato Firrao, Politecnico di Torino

2:00 PM
Dynamic Mechanical Behavior and Microstructure Evolution of Quinary Cu-Mn-Ni-Zn-Al Alloys: John Lauria¹; Kevin Laws¹; Juan Escobedo-Diaz¹; Hongxu Wang¹; Zongjun Li¹; Ali Ameri¹; ¹University of New South Wales
    Soldiers often carry large amounts of weight in ammunition; therefore, finding ways to reduce the weight could be lifesaving on the battlefield. The aim of this study is to develop a material that is stronger, lighter and cheaper than cartridge brass. The mechanical behaviour of five selected quinary copper alloys (multiphase/ high entropy alloy) and cartridge brass were investigated. Testing included quasi static, dynamic and impact tests using a universal testing machine, Split Hopkinson Pressure Bar (also known as Kolsky bar) and a single stage light gas gun (Taylor test), respectively. Microstructural examination (optical microscopy) and Vickers hardness testing is used in conjunction to further characterise the specimens. This study may prompt increased utilisation of quinary/high entropy alloys, which in turn, could lead to further revolutionary discoveries in the development of new materials.

2:20 PM
Temperature, Pressure, and Current Effects on Densification and Mechanical Properties of Nano-grained FeNiZr Consolidated via the Field Assisted Sintering Technology: Sean Fudger¹; Tom Luckenbaugh²; A.J. Roberts¹; Chad Hornbuckle¹; Franklin Kellogg³; Chris Haines¹; Kris Darling¹; ¹U.S. Army Research Laboratory; ²Bowhead Total Enterprise Solutions, LLC; ³SURVICE Engineering Company
    An oxide-dispersion-strengthened (ODS) nanostructured FeNiZr alloy wwas fabricated via high energy mechanical alloying and subsequently consolidated via the field assisted sintering technology (FAST). Input parameters of temperature, pressure, and current were varied in an effort to achieve full densification and optimize the mechanical performance following consolidation. As processing variations result in a wide range of material properties, tensile samples were generated and tested to accurately quantify the mechanical response of the material. Subsequently scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were performed to establish the relationship between processing, microstructure, and the resulting mechanical properties.

2:40 PM
Effect of Microstructure on Cleavage Fracture of Thick Section Quenched and Tempered S690 High Strength Steel: Virginia Bertolo¹; Quanxin Jiang¹; Carey L. Walters²; Vera Popovich¹; ¹Delft University of Technology, Department of Materials Science and Engineering; ²TNO, Structural Dynamics
    One of the main challenges in applying thick-section high strength steels (HSS) at low temperatures is to maintain a sufficient level of toughness to prevent cleavage failures. Cleavage fracture exhibits strong sensitivity to microstructure, and hence, microstructural investigation is of paramount importance. An aspect that requires special attention is the through-thickness microstructural variation which may result in different mechanical responses. In this study, the through-thickness microstructure and mechanical properties of 80mm S690QT HSS plate were investigated. The mechanical characterization was performed via tensile and CTOD testing at -100°C and microhardness testing. Microstructural characterization and fracture surface investigation were conducted using SEM, LECO and XRF analysis. Results show that the middle of the plate presents inferior properties compared to the outside positions which is associated to the non-uniform microstructure with local centreline segregation bands and larger grain sizes as well as larger hard and brittle inclusions, acting as crack initiation sites.

3:00 PM
In-situ Investigation of Thermal Characteristics of Novel Flash Processing Technique for Production of Advanced High Strength Steel (AHSS): Artem Trofimov¹; Hsin Wang¹; Thomas Watkins¹; Thomas Muth¹; Sudarsanam Babu²; Gary Cola³; ¹Materials Science & Technology Division, Oak Ridge National Laboratory; ²Department of Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee; ³SFP Works LLC
    AHSS is a focus of automotive and steel industries due to promising combination of high strength, lower weight, and good formability. However,utilization of AHSS is limited, in part, due to expensive alloying additions and/or energy intensive thermomechanical processing. Recently, Flash processing has shown potential to produce low-cost steel with high strength and good formability under cold stamping of complex shapes. The process consists of a rapid heating of steel sheets above 1000⁰C followed by quenching. At present, there is a lack of knowledge on thermal characteristics of Flash processing and their influence on structure-properties of created AHSS. In this work,AISI1020 steel sheets are Flash-processed at four peak temperatures from nominally 1075 to 1225⁰C; the thermal distributions across the length scale of the sheets are characterized with in-situ thermal imaging. Hardness measurements are correlated to the spatial locations and temperature on the sheets to understand the impact of the peak temperature.

3:20 PM
Tensile Characterization of Austempered Ductile Iron in Aquatic and Gaseous Environments: Dragan Rajnovic¹; Olivera Eric Cekic²; Leposava Sidjanin¹; ¹University of Novi Sad, Faculty of Technical Sciences, Serbia; ²University of Belgrade, Faculty of Mechanical Engineering, Innovation Centre, Serbia
    Austempered ductile iron (ADI) is an advanced type of heat treated ductile iron, with excellent combination of mechanical properties, which are comparable to forged steels. However, in recent publications it was established that in contact with water the ductility of ADI decrease. Despite notable scientific attention, the cause of this phenomenon remains unclear. Some authors suggested that a small atom chemisorption causes the weakening of the surface atomic bonds. To test proposed hypothesis, two different types of ADI materials were tensile tested in various environments, such as: argon, helium, hydrogen gas and water. It was discovered that only the hydrogen gas and water gave a statistically significant decrease in mechanical properties, i.e. cause embrittlement. Thus, the primary deteriorating effect on the ADI material tensile properties comes from hydrogen atoms. The morphology of the embrittled zone indicates that the brittle zone may be caused by cyclic local-chemisorption, micro-embrittlement and local-fracture.

3:40 PM Break

3:55 PM
Effect of Thermal Aging on Impact Toughness of Electron Beam Welded AISI 316 Stainless Steel: Arun Kumar¹; Sandeep Sandhu¹; Beant Singh²; ¹Quest Engineering College; ²PCET lalru
    Thick section of AISI 316 SS are widely used in jet engines, furnace parts etc. because of its corrosion and pitting resistance properties at high working temperature. In this paper, single pass square butt welding of 18mm thick plates, using electron beam welding at constant accelerating voltage 150 kV, beam current 90 mA, welding speed 600 mm/min and beam oscillation in circular pattern was investigated. The impact toughness and metallurgical properties in as welded condition and after thermal aging at 750°C for 24 hours were also investigated.The full penetration was achieved in single pass by optimizing the welding parameters. The results showed that welding of plates without filler metal lead to defect free welds. The average impact toughness at cryogenic temperature (-40°C) in as welded samples was recorded as 284J and after aged at 750°C for 24 hours it reduced to 180J.

4:15 PM
Connecting Dynamic Strain Aging to Deformation Processing in Magnesium-calcium-based Alloys: Wesley Cuadrado-Castillo¹; Michele Manuel¹; ¹University of Florida
    Fuel consumption can be improved by reducing car weight with substitution of aluminum and steel parts with magnesium (Mg). Magnesium formability at room temperature is limited due to strong basal texture generated prior processing. Shear band nucleation, observed under conditions in which dynamic strain aging (DSA), have been attributed to be responsible for texture weakening in dilute Mg – Rare Earths (RE) alloys. A low–cost substitution of RE is calcium (Ca) with similar atomic size. It is hypothesized that deformation of Mg – Ca alloys under DSA conditions improves Mg formability. In this study, Mg–Ca and Mg–Ca–Zn alloys were characterized using optical microscopy, XRD, and SEM/EDS. Compression testing was performed between 200 and 300C at different strain rates to observe DSA behavior. This work was performed under DOE Award Number DE-EE0007756.

4:35 PM
Microstructure Evolution During Tensile Deformation of Polycrystalline Cobalt: Frantisek Chmelik¹; Michal Knapek¹; Patrik Dobron¹; Mayerling Martinez²; Eric Hug²; ¹Charles University; ²Normandy University
    The microstructure evolution of polycrystalline cobalt (hexagonal close packed structure) in rolled condition and at different stages of tensile straining has been studied. The deformation mechanisms were identified by acoustic emission testing and transmission electron microscopy. Plastic deformation starts by dislocation glide which is accompanied by twinning, subsequently. Four single twinning modes were identified, from which two types correspond to tensile strain and two types to compressive strain (with respect to the c direction), double twins were also observed. A relative importance of various twinning systems is estimated and it is shown that the vast majority of twins correspond to the {10-12} twinning system.

4:55 PM
Deformation Behavior of Hexagonal Metals Investigated by the In-situ Acoustic Emission and Digital Image Correlation Techniques: Michal Knapek¹; Patrik Dobron¹; Frantisek Chmelik¹; ¹Charles University
    The acoustic emission (AE) and digital image correlation (DIC) techniques have been known to be particularly useful for the study of deformation dynamics in various solid materials. Recent advances in the signal analysis allow revealing the evolution of different deformation modes during loading. Moreover, deformation localization can be captured and effectively analyzed by DIC and even AE if the sample size is of at least several tens of mm. In this contribution, we present several novel results related to the abovementioned effects. The AE clustering analysis (based on the power spectral density evolution) and DIC identified differences in the evolution of deformation modes in hcp magnesium and cobalt samples. Furthermore, the effect of material parameters, such as grain size and texture, was assessed with respect to the active deformation mechanisms at the microstructural level.

5:15 PM
Determining Bulk Elastic Properties of Transversely Isotropic Aluminum Using Resonant Ultrasound Spectroscopy: Jordan Evans¹; Blake Sturtevant¹; Fedor Balakirev¹; Albert Migliori¹; Boris Maiorov¹; ¹Los Alamos National Laboratory
    Materials can have complex anisotropic mechanical properties depending on texture. In this study, samples with identical thermomechanical histories were machined from an extruded rod of aluminum alloy 1100-O in different orientations with respect to the rod axis. The samples’ elastic wave resonance frequencies were measured using resonant ultrasound spectroscopy (RUS). These resonances were used to (a) identify the orientation of the transversely isotropic axis due to texture from extrusion, and (b) quantify the degree of anisotropy by determining the entire elastic tensor of each sample (5 independent elastic constants) with one non-destructive RUS measurement. The anisotropy of the compressive (c₁₁ vs. c₃₃) and shear (c₄₄ vs. c₆₆) elastic constants are 0.72% ą 0.54% and 5.06% ą 0.50%, respectively, where c₃₃ and c₆₆ are the elastic constants associated with the textured axis. Anisotropic properties were confirmed by direct sound velocity measurements using the ultrasonic pulse-echo technique.