MSE Seminar Series: Investigation of Porosity, Texture & Defonnation Behavior Using High Energy...

Friday, April 9, 2021
1:00 p.m.
via Zoom
Sherri Tatum

Speaker: Aeriel Murphy-Leonard, MSE Assistant Professor at The Ohio State University

Full Title: Investigation of Porosity, Texture and Defonnation Behavior Using High Energy X-rays During In-Situ Tensile Loading In Additively Manufactured 3 l 6L Stainless Steel


The evolution of damage, texture, and strain in additive manufactured (AM) 316L stainless steel produced via laser powder bed fusion was investigated during in-situ tensile loading using high energy X-rays. Synclu·otron X-ray computed tomography (XCT) measurements were perfonned to determine the initial porosity and monitor the evolution of porosity during tensile loading as well as detect the initiation and growth of voids from pre-existing pore defects in the specimens. The as-built tensile specimens had a cross-sectional area of 1 mm2, which was chosen in order to understand damage behavior in thin-walled strnctures. Far-field X-ray diffraction measurements were perfonned to quantify c1ystallographic texture and the distribution of internal elastic strains during loading. The initial texture from the AM build process had a weak {220} texture aligned parallel to the build direction. As a result of tensile defonnation, a str·ong {lll} + {200} double fiber texture develops at high tensile str·ains and remains until fracture. XCT results confirmed that the inhomogeneous distr·ibution of porosity near the surface played a significant role in damage evolution during tensile loading where voids and cracks initiated at pre-existing pores located within the contour zone. These pores were found to have asymmetric or irregular morphology. At high tensile str·ains, the massive accumulation of internal damage at these pores eventually c01mected to the surface reducing the ductility in these thin-walled AM samples and resulting in fnal failure. 


Aeriel D.M. Leonard is an assistant professor in the Department of Materials Science and Engineering at The Ohio State University. She earned her bachelor's degree in Metallurgical and Materials Engineering from the University of Alabama in 2012. After that, Dr. Leonard worked in the Corrosion Research Group at Alstom Inc. for a year. In 2013, she began her PhD journey at the University of Michigan in Materials Science and Engineering where she earned her PhD in 2018. Dr. Leonard's PhD work investigated real-time microstructural and defonnation evolution in magnesium alloys using advanced characterization techniques such high energy diffraction microscopy and electron back scatter diffraction. During her time at Michigan she led and worked on many teams aimed at increasing the number of unde1Tepresented minorities in engineering including developing and implementing a leadership camp for female engineering students in Momovia, Liberia. Dr. Leonard was awarded an NRC Postdoctoral Fellowship at the US Naval Research Laborat01y in Washington DC where she worked for two years. During this time, she used advanced characterization techniques such as x­ray computed tomography and high energy diffraction microscopy to understand damage and texture evolution during in-situ loading in additive manufactured materials. She also rnns a lifestyle blog titled AerielViews aimed at young graduate and professional students.

Audience: Campus 

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