Andrew (Chihpin) Chuang, Ph.D.,Assistant Physicist, X-ray Science division of Advanced Photon Source, Argonne National Laboratory
The demand to produce a high-efficiency engine that is both lightweight and cost-effective is increasing rapidly in recent years. Current higher strength irons are difficult to cast in complex shapes with thin walls like engine blocks and cylinder heads, have poor thermal conductivity, and can require expensive heat treatments that adds to the higher casting costs. Over the years, improvements in cast iron materials have largely occurred by accident largely because the austenite-graphite eutectic solidification process is not well understood. The physical properties of cast irons are determined by the 3D morphology of the graphite and its spatial arrangement within the material. The classification of graphite in terms of size, distribution and type in cast irons is usually used to as a reference to concisely define the material being made. The development of high energy x-ray techniques in recent decades makes it a promising tool to provide a comprehensive description of the graphite morphology in the specimen. In this work, we utilized x-ray radiography and tomography techniques to perform 3D-characterization of graphite morphologies in different types of mixed graphite irons and the austenite-graphite eutectic solidification process. The goal aims to understand the microstructure that forms during the various stages of solidification and solid-state transformations and its relationship with the alloying, treatment, inoculation and casting conditions.
Andrew (Chihpin) Chuang, Ph.D., is an assistant physicist in Materials Physics & Engineering group in X-ray Science division of Advanced Photon Source at ANL. His research focus on using non-conventional, non-destructive synchrotron X-ray diffraction/scattering/imaging techniques (e.g. Energy-dispersive X-ray diffraction, high-energy x-ray tomography, high-energy diffraction microscopy) to study the structure-property relationship of engineering alloys and composites. He primarily collaborates with industry partners including Caterpillar, Pratt & Whitney, GE and Royce Rolls to develop solutions for real-world applications and problems. One of his project with Caterpillar aims to develop next generation high strength cast iron for heavy-duty vehicles. As a key contributor, he utilized X-ray tomography and radiography to investigate 3D morphology of graphite in cast iron, its relationship with process parameters and the growing mechanism during solidification. The work was reported by Journal of Synchrotron Radiation as APS facility highlight and by Foundry Magazine. Andrew received his Ph.D. degree in Materials Science and Engineering from the University of Tennessee (UT) at Knoxville in 2013. He joined Energy Systems Division in 2014 as a post-doctoral appointee before starting his appointment with XSD in 2016.
Host: Dr. Sheng-Wei Chi