4th International Congress on 3D Materials Science (3DMS) 2018: Phase Transformations, Particle Coarsening, Grain Growth, and Recrystallization IV
Program Organizers: Hugh Simons, Denmark Technical University; Henning Poulsen, Denmark Technical University; David Rowenhorst, Naval Research Laboratory; Peter Voorhees, Northwestern University; Satoshi Hata, Kyushu Univ; McLean Echlin, UC Santa Barbara
Wednesday 1:30 PM
June 13, 2018
Room: Lille Scene
Location: Kulturværftet (Culture Yard) Conference Center
Session Chair: Anter El-Azab, Purdue University
Quantification of Inter Diffusion for Ceramic/Metal Interface with 3D-SIMS: Lei Zhang1; Chunli Dai1; Jie Zhang1; 1Institute of Metal Research, Chinese Academy of Sciences
Layering images of diffusion species by TOF-SIMS analysis can be reconstructed in 3D and reveal chemical information at interfaces with resolution down to nanometer in both lateral and longitudinal direction. This 3D-SIMS analytics tool facilitates the quantification of Inter diffusion of ceramic/metal interfaces, which is crucial to tell the bonding in between. In terms of the 3D-SIMS views of Al+, Cr+ and Zr+ ions in the TiAlC coating and Zr substrate, diffused Al and Cr were clearly observed in both as-deposited and annealed states. Quantification results of stoichiometric ratio indicated that Cr diffused more than Al. By Gaussian convolution of the 3D-SIMS data, the counts density of investigated species was transformed into quasi-concentration space. The concentration contour can be given and exhibited the relationship relative to the initial interface in 3D view. It shows that the diffusion front was uneven and Cr diffused more and further than Al.
4D X-ray Tomography Investigation of Dendrite Evolution in Al Alloys: Tiberiu Stan1; Yue Sun1; Kate Elder1; Xianghui Xiao2; Michel Rappaz3; Peter Voorhees1; 1Northwestern University; 2Argonne National Laboratory; 3Ecole Polytechnique Federale de Lausanne
The mechanisms by which metallic dendrites grow remain controversial and not well understood. The 4D evolution of dendritic two-phase mixtures in Al-Cu and Al-Zn alloys is determined using coupled in-situ x-ray computed tomography (XCT) and x-ray diffraction (XRD). The experiments give new information about: solid-liquid volume fractions, dendrite tip growth rates and morphologies, secondary branch spacings and symmetries, interfacial curvatures and areas, and coarsening dynamics. Conventional Al – 20 wt% Zn alloys solidify via fcc Al dendrites which grow in <100> directions. The addition of just 0.1 wt% Cr leads to twinned dendrites which instead grow in <110> directions. It is postulated that the Cr addition forms metastable five-fold symmetric quasicrystals with edges that favor the nucleation of twinned dendrites. The combination of 4D XCT and XRD techniques used in this study provide new insights into the growth of regular and twinned dendrites in metallic alloys.
3D-XRD Study of Phase Transformation Microstructures in Deep Earth Minerals: Sebastien Merkel1; Christopher Langrand1; Angelika Rosa2; Volodymyr Svitlyk2; David Dobson3; Nadège Hilairet1; 1Universite de Lille; 2ESRF; 3University College London
Hydrostatic pressure has a profound effect on the properties of materials. In the Earth's mantle for instance, minerals undergo series of phase transformations with implications for its structure and dynamics. Here, we use multigrain crystallography combined with high pressure / high temperature experiments in diamond anvil cells in order to asses the effect of phase transformations on deep Earth minerals microstructures.We focus our study on a perovskite (Pv) to post-perovskite (pPv) transformation, both orthorhombic structures. A polycrystal of NaCoF3 is compressed up to 30 GPa at 900 K, inducing the Pv-pPv transformation, and decompressed, inducing the reverse transformation. Using in-situ measurements, we study the induced microstructures (grain orientations, grain sizes, etc) and the corresponding transformation mechanisms. The results have important geophysical implications. They also demonstrate the relevance of the technique for other geophysical systems but also in other scientific fields for which high pressure transformation microstructures are relevant.
Internal Stress and Damage Evolution during Loading of Additively Manufactured Stainless Steel: Bjorn Clausen1; Reeju Pokharel1; Timothy Ickes1; Darren Pagan2; Joel Bernier3; Donald Brown1; George Gray1; 1Los Alamos National Laboratory; 2Cornell University; 3Lawrence Livermore National Laboratory
Additive manufacturing (AM) of metals has the potential to revolutionize the manufacturing industry; however, significant challenges remain before it can be qualified as a transformative metal component fabrication technique. We will present the results of in-situ HEDM and tomography measurements during tensile loading of as-built and heat treated AM 304L stainless steel (SS). The measurements were performed using the RAMS2 load frame on the F2 instrument at CHESS. Near-Field, Far-Field HEDM and tomography were invoked for the heat treated AM SS to monitor the development of internal stresses and void/fracture. The initial microstructure of the as-built AM SS did not lend itself to HEDM measurements as the grain size is very small and the dislocation density is relatively high, but powder diffraction measurements of average internal stress and texture as well as tomography measurements to determine the void formation and fracture of the material was applied during the loading.
Coarsening Statistics in an Iron Polycrystal and Advances in Grain Boundary Energy Extraction: Yu-Feng Shen1; Xiaoting Zhong1; He Liu1; Aditi Bhattacharya1; Gregory Rohrer1; Robert Suter1; 1Carnegie Mellon University
Near-field High Energy x-ray Diffraction Microscopy (nf-HEDM) is used to track the three dimensional microstructural evolution of an alpha phase iron sample under thermal annealing. We study the evolution of grain and grain boundary statistics. By matching grains across the two measured states, we track thousands of grains as they evolve, along with the movements of grain boundaries. Further, we present new solution methods and a new algorithm for extracting relative grain boundary energies based on observations of large numbers of triple junction topologies. Accelerated convergence of the original Morawiec formulation of the problem is achieved with modern optimization methods. A new formulation will be presented that avoids the limitations of binning of the five dimensional space of grain boundary character.
3:10 PM Break