Characterization of Minerals, Metals, and Materials: Non-Ferrous Metals
Sponsored by: TMS Extraction and Processing Division, TMS: Materials Characterization Committee
Program Organizers: Shadia Ikhmayies, Al Isra University; Bowen Li, Michigan Technological University; John Carpenter, Los Alamos National Laboratory; Jian Li, CanmetMATERIALS; Jiann-Yang Hwang, Michigan Technological University; Sergio Monteiro, Military Institute of Engineering ; Firrao Donato, Collegio Universitario, Italy; Mingming Zhang, ArcelorMittal Global R&D; Zhiwei Peng, Central South University; Juan P. Escobedo-Diaz, UNSW Australia; Chenguang Bai, Chongqing University; Eren Kalay, METU; Ramasis Goswami, Naval Research Laboratory; Jeongguk Kim, Korea Railroad Research Institute

Thursday 2:00 PM
March 2, 2017
Room: 31A
Location: San Diego Convention Ctr

Session Chair: Ramasis Goswami, Naval Research Laboratory; Farzad Foadian, Clausthal University of Technology

2:00 PM  
Defect Structures in the Intermetallic Compounds Ag3Sn and Cu3Sn: Haibo Yu1; Yu Sun1; Seok-Woo Lee1; Paul Canfield2; S. Pamir Alpay1; Mark Aindow1; 1University of Connecticut; 2Ames Laboratory & Iowa State University
    The intermetallic compounds Ag3Sn and Cu3Sn, were originally described as being iso-structural with the orthorhombic D0a (Cu3Ti-type) structure. In subsequent studies it was shown that equilibrium form of Cu3Sn is a long-period variant of the D0a structure. It has been established previously that the Ag3Sn is inherently ductile, whereas Cu3Sn exhibits very brittle behavior. In our studies we have used transmission electron microscopy investigate the defect structures that develop in the two phases. These observations are used to gain an insight into the different deformation micro-mechanisms that operate, and thus to elucidate the dramatic differences in ductility. In pseudo-binary Ag3Sn-Cu3Sn alloys we find that the Ag3Sn phase deforms mainly by dislocation glide, whereas the Cu3Sn phase deforms by twinning. These observations are compared with data from experiments on deformed samples of pure Ag3Sn and Cu3Sn, to reveal the roles of solute atoms and heterophase interfaces on the deformation mechanisms.

2:20 PM  
Mechanical Behavior of Light Metal Alloys with Grain Size Distribution in a Wide Range of Strain Rates: Vladimir Skripnyak1; Vladimir V. Skripnyak1; Evgenia Skripnyak1; Irina Vaganova1; Natalia Skripnyak1; 1National Research Tomsk State University
    Mechanical behavior of aluminum (Al-Mg-Si – AMg6) and magnesium (Mg-Al-Zn-Mn – МА2 and MA8) alloys with a distribution of grain size was investigated under uniaxial tension in wide range of strain rates. The grain size distributions were created in thin sheets of alloys by severe plastic deformation using the technique of groove pressing or ultrasonic impact treatment. The occurrence of a bimodal grain size distribution causes the increase of alloy’s ductility, but decrease of the tensile strength. Strain to fracture of alloys depends on the relative volumes of ultrafine-grains. The multiscale model was developed for prediction of plastic deformation and fracture of alloys with a unimodal and a bimodal grain size distribution under dynamic loading. Macroscopic fracture is considered as a result of the formation of percolation clusters of damage at the mesoscopic level. The nucleation of damages under loading is associated with strain localization in UFG partial volumes.

2:40 PM  
Microstructure Evolution during Thermo-mechanical Processing of Low-symmetry Metals: Rodney McCabe1; Miroslav Zecevic1; Daniel Coughlin1; Sven Vogel1; Bjorn Clausen1; Donanld Brown1; 1Los Alamos National Laboratory
    Using electron backscatter diffraction (EBSD) and neutron diffraction, we examine the microstructure evolution accompanying deformation processing and recrystallization. The EBSD data allows us to draw statistical correlations between microstructure features in the deformed microstructures with the resulting recrystallized microstructures. The neutron diffraction allows us to examine in situ the exact same sample volume during deformation and then during recrystallization. For each deformation condition, the recrystallization texture weakens relative to the deformation texture, but without development of strong components that were not strong in the deformed material. The recrystallization textures agree well with textures derived from a subset of scan points in the deformed microstructures adjacent to high angle grain boundaries (HAGBs). In addition, the areal number density of recrystallized grains exhibits dependencies on the linear density of HAGBs in the deformed microstructures. Implications of these findings towards modeling of deformation and recrystallization in uranium will be discussed.

3:00 PM  
A Comparison of Gallium and Xenon Plasma Focused Ion Beam Techniques for the Interrogation of Aluminum Alloy Microstructures: Alexis Ernst1; Mei Wei1; Mark Aindow1; 1University of Connecticut
    Over the last 20 years, dual-beam FIB instruments using liquid metal Ga ion sources have become essential tools for the microstructural characterization of materials. Factors that have contributed to this include: the integration of hardware for EDXS, EBSD and in situ lift-out of TEM specimens. While these approaches provide an invaluable insight into structural development in many materials systems, the maximum milling rates that can be achieved are insufficient for the analysis of some metallurgical systems die to the length scales involved. More recently, dual-beam FIB instruments have been developed with inductively coupled plasma Xe ion sources. These ion columns give milling rates that are 10-100x higher than for Ga ion columns, enabling much larger areas/volumes to be interrogated. Here we will compare the use of these two types of FIB instruments to study a range of advanced powder-processed Al alloys to demonstrate the relative advantages of the two approaches.

3:20 PM  
Effect of Alloying Elements on Diffusing Bonding Parameters in Al6063 Alloy: Sıla Atabay1; Arcan Dericioglu1; 1Middle East Technical University
     During diffusion bonding, high temperatures involved in the process cause grain growth deteriorating the mechanical properties of the base metal. To overcome this problem process time could be shortened by increasing the kinetics of the bonding or grain growth could be prevented by segregation of new complexes at the grain boundaries.In this study, DB parameters were optimized for Al6063 alloy. To prevent grain growth without altering the composition Gold and Nickel were used as interlayer materials to shorten bonding time. However, interlayer addition showed a decreasing trend in bond strength. In this respect, Xx(X: Sn, Cu and x:0.5-5wt%) was added to the alloy to see the effect of these elements on grain growth and bond strength. Effects of these treatments were characterized via combined study of optical microscope, SEM, EDS and XRD. Mechanical properties of the joints are determined via shear testing, and results were discussed in detail.

3:40 PM Break

3:55 PM  
Composition Dependent Martensitic Transformation and Softening of Elastic Constants: Le Zhou1; Abhishek Mehta1; Anit Giri2; Kyu Cho3; Yongho Sohn1; 1University of Central Florida; 2SURVICE Engineering Company; 3US Army Research Laboratory
    Martensitic transformation is commonly observed in ordered alloys where austenitic phase diffusionlessly transforms to martensitic phase. In this study, solid-to-solid diffusion couples in binary Ni-Al and ternary Ni-Mn-Ga systems were annealed and analyzed by SEM, TEM and nanoindentation to examine the martensitic transformation of β-NiAl (B2) and Ni2MnGa (L12) upon cooling to room temperature. Composition variation created during diffusion anneals yielded composition-dependent transformation where one side transformed to martensite and the other retained the high temperature phase. In both alloy systems, composition dependent reduced elastic modulus and hardness were obtained. A minimum value near the austenite/martensite interphase boundary was consistently observed, which can be explained by softening of the elastic constants (i.e., lattice softening) prior to the martensitic transformation. Microscopic and nano-indentation results are presented with respect to the compositional changes and composition-dependent martensitic transformation, and their significance is discussed for shape memory alloys and high temperature alloys.

4:15 PM  
Study of Texture Evolution in Copper Tubes Due to the Tilting of the Die during Drawing: Farzad Foadian1; Mohammad Masafi1; Adele Carradó2; Heinz-Günter Brokmeier1; Heinz Palkowski1; 1Clausthal University of Technology; 2Institut de Physique et Chimie des Matériaux de Strasbourg
    In this work, based on the results of the previous work – variation of the eccentricity and residual stresses measured by neutron diffraction method – a tube, which was drawn with a die with 5° of tilting, was chosen to study the local evolution of the texture. The texture gradient of the as-received tubes as well as the ones of the drawn tubes was studied using synchrotron diffraction method at HEMS@Petra III in Hamburg/Germany. In order to understand the deformation process during drawing, the deformation zone was investigated as well. For this reason, the drawing process was interrupted. Understanding the texture behavior during the drawing process with tilted die helps to be able to describe the flow behavior and gives a better understanding of the effect of this asymmetrical behavior on the other mechanical and physical properties.

4:35 PM  
Recrystallization Behavior of Al Added Low Density Medium Mn Steel: Arnab Sarkar1; Tapas Bandhyopadhay1; 1Indian Institute of Technology,Kharagpur
    Low SFE in the medium Mn range is responsible for the poor mechanical properties of automotive steel. Addition of the Al enhances the overall SFE of the alloy. But the high SFE prefers recovery over recrystallization. So the present work is to study the recrystallization behavior of Al added low density medium Mn steel during annealing of the forged, hot rolled and cold rolled specimens at 1000ᵒC.The overall recrystallized fraction is evaluated from GOS calculation after the EBSD analysis. The cold rolled specimen recrystallizes faster than the forged and hot rolled specimen. It is due to the presence of larger stored energy during deformation. Crystallization rates are estimated from Johnson-Mehl-Avrami equation. It states about migration of the dislocation along the grain boundary during annealing.

4:55 PM  
Texture Patterns in Orientation Gradient Ta Thin Films: Elizabeth Ellis1; Markus Chmielus2; Marissa Linne3; Shefford Baker1; 1Cornell University; 2University of Pittsburgh; 3University of Michigan
    Since the discovery of the metastable beta phase of tantalum in 1965, much effort has focused on the parameters required to deposit a Ta film a particular phase. However, comparatively little work has been done on the transformation from the beta phase to the stable alpha phase. We have shown that Ta films deposited in the beta phase and transformed to the alpha phase show an unusual microstructure featuring long-range orientation gradients. Furthermore, EBSD reveals that variations in the initial film structure created by depositing under different sputter pressures have dramatic effects on the magnitude of the resulting orientation gradients and associated texture patterns. Pole figure analysis reveals many interesting features of these patterns, including the fact that seemingly unrelated film areas separated by large distances are actually parts of the same structure. We analyze these patterns to suggest a nucleation and growth sequence by which they might form.

5:15 PM  
Characterization of Surface Microstructure and Passive Film Formed on Nanostructured Ti-6Al-4V Alloy Produced by Cryogenic Burnishing: Jun Tang1; Hongyun Luo1; 1Beijing University of Aeronautics and Astronautics
    On the surface layer of Ti-6Al-4V alloy produced by cryogenic burnishing, reduced surface roughness, refined grain structure, and obviously improved corrosion resistance are achieved. The surface roughness (Ra=0.32 μm) of cryogenic burnished sample is much lower than that of dry burnished sample. Homogeneous and random nano-grains (less than 20nm) and high dislocation density (2×1017m-2) were obtained on the surface layer of burnished sample analysed by transmission electron microscopy (TEM). X-ray diffraction (XRD) results show that there is no development of texture after burnishing. The passive film of samples before and after burnishing in a 0.9 % NaCl solution was investigated by electrochemical and X-ray photoelectron spectroscopy (XPS) techniques from which it could be deduced that the passive film formed on burnished samples is more protective, less defective and 1.5 times thicker than that of the unburnished counterparts due to the high density of grain boundaries and dislocations.

5:35 PM  
Formation of Three Dimensional ZnO Micro Flowers from self Assembled ZnO Micro Discs: Shadia Ikhmayies1; 1Al Isra University
    Zinc oxide (ZnO) three dimensional micro flowers of average diameter 1.1 ± 0.25 µm were produced in this work by the spray pyrolysis (SP) method in thin film form on glass substrates at a substrate temperature of 350 ± 5 {degree sign}C. X-ray diffraction revealed that the films are hexagonal (wurtzite) with high crystallinity and prefered (002) orientation. Scanning electron microscope (SEM) images revealed the morphology of the films, which consists of hexagonal microdiscs and self assembled microdiscs into three dimentional micro flowers. The hexagonal microdiscs have noticable thickness and average side of 500 ± 130 nm. The micro flowers have an average diameter of 1.1±0.25 µm. The micro flowers have hexagonal shapes, and some of them are linked togother to form larger three dimensional structures. Assembling of the micro discs and formation of the three dimensional hexagonal flowers occurred during the deposition process without the aid of any surfactant. X-ray energy dispersive spectroscopy (EDX) showed that the films are non stoichiometric and they contain chlorine besides Zn and O. These three dimensional flowers are of potential use in several technological applications such as gas sensors, electronic devices, and solar cells.