Characterization of Minerals, Metals and Materials 2022: Advanced Characterization Methods II
Sponsored by: TMS Extraction and Processing Division, TMS: Materials Characterization Committee
Program Organizers: Mingming Zhang, Baowu Ouyeel Co. Ltd; Jian Li, CanmetMATERIALS; 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; Rajiv Soman, Eurofins EAG Materials Science LLC; Zhiwei Peng, Central South University

Thursday 8:30 AM
March 3, 2022
Room: 207B
Location: Anaheim Convention Center

Session Chair: Kelvin Xie, Texas A&M University; Rajiv Soman, Eurofins EAG Materials Science LLC


8:30 AM Introductory Comments

8:35 AM  
Analysis of MoNbTi and HfNbTaTiZr Refractory High Entropy Alloys by Atom Probe Tomography: Patrick Callahan1; David Beaudry2; Keith Knipling1; 1Us Naval Research Laboratory; 2Johns Hopkins University
    High entropy alloys (HEAs) have a significantly expanded composition space from traditional alloys as they are composed of multiple principal elements. There are numerous novel alloys to study given the large composition space of HEAs, and still a number of fundamental questions need to be addressed regarding properties in HEAs, such as plasticity and the mechanisms of dislocation motion, and diffusion. Atom probe tomography enables the accurate observation of the composition and morphology from targeted regions of materials and microstructural features near the atomic scale from ~200x200x100 nm3 volumes. In this study, the multi-hit detection events in two refractory HEAs, MoNbTi and HfNbTaTiZr, were analyzed. Multi-hit events comprise a significant number of detected ions in these alloys, for example ~35 - 40% of Mo and Nb ions that are collected. The consequences of these multi-hit events on quantitative APT measurements in these alloys will be discussed.

8:55 AM  
On the Phase Composition, Properties and Application of AlMgB14-based Materials: Ilya Zhukov1; Pavel Nikitin1; Alexander Vorozhtsov1; 1Tomsk State University
    Ultra-hard wear-resistant materials are of great interest for industrial applications. At the same time, the search for a wear-resistant material with an acceptable cost and competitive properties seems to be relevant. One of these materials is AlMgB14. It combines high hardness (32-46 GPa) and low coefficient of friction (COF, 0.02-0.08). In this work, hard wear-resistant ceramic materials based on AlMgB14 were sintered from Al12Mg17-B powder mixture by powder metallurgy methods (hot pressing, spark plasma sintering, self-propagating high-temperature synthesis). The phase composition, structure and properties of the obtained materials have been studied.

9:15 AM  
TEM Characterization of an AS7G06 Alloy with Several Heat Treatments: Nicolas Bello1; Cassiopée Galy2; Céline Larignon2; Joël Douin1; 1CEMES-CNRS; 2IRT Saint Exupéry
     On an AS7G06 alloy elaborated by laser beam melting, transmission electron microscopy observations and thermal analysis experiments have been conducted. Several characterizations were performed on the as-built microstructure and after several heat treatments to understand the phase transformation influence on the mechanical properties of an LBM-Al-Si-Mg alloy.The 3D Si-cell structure observed in as-built LBM alloys is present and persists after the direct artificial ageing heat treatment. This structure is maintained up to 280°C when heated and exists throughout an ageing treatment at 150°C. Second, all investigated heat treatments lead to a partial precipitation of b’’ responsible for the good mechanical properties of the alloy. To complete this work, a comparison between the tensile mechanical properties of all thermal states and the associated microstructure is presented.​​​​

9:35 AM  
Sample Preparation Influence on a Direct Artificially Aged Al-Si-Mg Alloy Elaborated by Laser Beam Melting: Nicolas Bello1; Cassiopée Galy2; Céline Larignon2; Joël Douin1; 1CEMES-CNRS; 2IRT Saint Exupéry
     Fine microstructure of aluminium alloys is known to be strongly affected by temperature hence the need to control the temperature during the sample preparation process. For this study, a direct artificially aged Al-Si-Mg alloy is used. This alloy was obtained by laser beam melting and is composed by a complex microstructure featuring nano-sized precipitates and a silicon 3D structure. Direct artificial ageing was conducted to stabilize the alloy and enhance mechanical properties.The comparison of several TEM preparation techniques showed the classical twin jet benefit for a more defined aluminium cell with fewer effects on the Si-structure. The observed Si-network is thinner with the use of PIPS and FIB techniques. These techniques induce a strong modification of the nanoprecipitates observed in the microstructure due to the local heating and ion irradiation. However, the cryogenic temperature combined with the FIB technique seems to be equivalent with the twin jet electropolishing.

9:55 AM  
Ion-irradiation-induced Property Change in FeCr: Hardness, Thermal Diffusivity and Lattice Strain: Kay Song1; Suchandrima Das1; Abdallah Reza1; Nicholas Phillips2; Ruqing Xu3; Hongbing Yu4; Kenichiro Mizohata5; David Armstrong1; Felix Hofmann1; 1University of Oxford; 2Paul Scherrer Institut; 3Argonne National Laboratory; 4Canadian Nuclear Laboratories; 5University of Helsinki
    The study of FeCr binary alloys provides fundamental insights into irradiation damage and defect behaviour without the microstructural complexities of steels for fusion materials. We present a systematic study of Fe3Cr, Fe5Cr and Fe10Cr alloys implanted to 0.01 dpa and 0.1 dpa. Our results from nanoindentation and X-ray diffraction suggest that Cr leads to an increased retention of irradiation-induced defects, causing substantial changes in hardness and lattice strain. The degradation of thermal diffusivity, measured by transient grating spectroscopy, was found to be dominated by the presence of Cr while the effect of the defect population is small. We find significant lattice strains which cannot be fully account for by the visible defects observed in TEM, suggesting that TEM may not fully capture the irradiation-induced defect population. The comparison of trends across different material properties reveals unique insights into the behaviour of defects and their effect on the FeCr material system.