3D Grain Mapping Using X-ray Microscopy: Advances in Laboratory-based Diffraction Contrast Tomography (LabDCT)

Thursday, August 6 | 2:00 pm EDT

Hrishikesh Bale, Ph.D.

Carl Zeiss X-ray Microscopy

Dr. Hrishikesh Bale is the Market Solutions Manager for Engineering Materials at ZEISS Microscopy. He has been working in the area of advanced composites and structural materials for over 20 years. His research focus lies in advanced materials characterization using in situ micro and nano-mechanical testing using X-ray computed tomography. He also specializes in new applications development for laboratory 3D X-ray diffraction imaging techniques both at micro and nano scale. Before joining Carl Zeiss Microscopy in 2014, he held a joint post-doctoral scholar appointment at Lawrence Berkeley National Laboratory and UC Berkeley in the Material Science and Engineering department working as part of the National Hypersonics Science Center, imaging advanced CMC materials under in situ high-temperature conditions. He received his Ph.D. in Materials Science from Oklahoma State University in 2010 with a focus on microscale residual stress determination using Synchrotron Laue Microdiffraction techniques. He lives in the San Francisco Bay Area.

Abstract

Mechanical, thermal, electrical, and optical properties of materials are frequently linked directly to the microstructure, including three-dimensional grain characteristics like size, morphology, and orientation. Control over these aspects of the microstructure can accordingly be used to tune the performance of materials in diverse ways. Microscopists have classically employed techniques including polarized light microscopy and EBSD to probe these structures in high resolution across a 2D cross-sectional plane. Obtaining 3D data has been achieved by a mix of serial sectioning using either mechanical polishing or ion beam milling, with the trade-off that the observed structure of the material is consumed in the process.

Probing with X-rays provides an attractive alternative, offering signal penetration into and out of a sample’s interior nondestructively. Early implementations of this Diffraction Contrast Tomography approach have emerged from a few select synchrotron facilities worldwide, with exciting research opportunities but limited user access. However, recent advances in X-ray sources, detectors, and algorithm development have opened the door for new, powerful, and widespread applications for 3D grain mapping within a laboratory setting.

In this talk we will present the latest technology in lab-based diffraction contrast tomography, LabDCT, implemented on the ZEISS Xradia 620 Versa X-ray microscope. We will cover a brief overview of the working principles, and then discuss numerous applications covering a spectrum of material systems from highly symmetric cubic materials to some of the low-symmetry materials that were previously challenging to investigate.

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