Abstract

The last decade has seen tremendous advances in the ability of X-rays and neutrons at large scale facilities to probe microstructure at unprecedented length and time scales under unique environments that simulate manufacturing conditions. Concurrently, manufacturing is undergoing a revolution as investments are made in advanced manufacturing techniques, such as additive manufacture.  It is natural that advanced manufacturing techniques should couple with advanced in-situ characterization techniques in order to accelerate the process of qualification of products for critical applications. This talk will present our efforts to characterize the processing/microstructure/properties/performance relationship of additively manufactured materials across many length and time scales utilizing both neutron and high-energy x-ray scattering techniques.  As an example of studying the effect of processing on microstructure, high energy x-ray diffraction has been used to monitor microstructural evolution in-situ during additive manufacture of 304L stainless steel with sub-second time resolution and sub 0.1mm spatial resolution. Specifically, the evolution of phase fractions, liquid and multiple solid phases, is monitored immediately following deposition. On larger time and length scales, neutron diffraction has been used to monitor microstructural evolution in-situ during post-deposition heat treatment of stainless steel, an integral part of metal additive manufacture. The study is extended to include the linkage of processing to properties through in-situ neutron diffraction measurements during deformation of additively manufactured materials.

Biography

Don Brown received his PhD in Physics from the Penn State University in 1998 focusing on using x-ray and neutron scattering techniques to characterized materials confined to nano-voids.  He began his career as a postdoc working at the neutron scattering center at Los Alamos National Lab.  He has been the lead instrument scientist since the commissioning of the Spectrometer for Materials Research at Temperature and Stress (SMARTS) in 2003 until now. SMARTS was the first neutron scattering instrument designed for the study of engineering materials and is based on a philosophy of studying materials response to conditions simulating operation and/or processing conditions.  Don has extended this philosophy to include large scale x-ray scattering facilities such as the advance photon source at Argonne National Lab. His work has focused on the study of nuclear weapons and energy materials, but included components of aerospace, automotive, and functional materials as well. Most recently, his research has included in-situ processing and performance of additively manufactured materials.