3D In-situ Stop Action Study of Recrystallization in Additively Manufactured 316L Stainless Steel: Reconstruction Optimization and Observations

Abstract

A volume of an additively manufactured 316L stainless steel sample has been tracked during its recrystallization using near- and far-field High Energy Diffraction Microscopy (HEDM) and absorption tomography at Advanced Photon Source beamline 1-ID. A near-field compatible in situ furnace allows monitoring of Bragg diffraction signals as they evolve out of a weak and diffuse background while the sample temperature is ≈ 1250° C. The sample is rapidly cooled to room temperature after observation of significant signal evolution and ∼ 0.035 mm3 is mapped by the near-field method. Four cycles of heat treatment follow the structure from a state of small, isolated grains through impingement of domains to near completion of recyrstallization. Here, the experiment and reconstructions are described, and recrystallized fractions, twin domains, and distributions of grain boundary types are discussed.

Modeling of experimentally observed topological defects inside bulk polycrystals

“…For example, comparisons have been made between observed plastic behaviors and model expectations including twinning [7], grain rotation and breakup [8,9] as well as crack nucleation and propagation [10][11][12]. Studies of thermal responses include recrystallization [13][14][15] coarsening [16][17][18][19] and phase transformations leading to abnormal grain growth [20]. These studies provide direct experimental observations that can and are being used to develop improved models of materials responses.…”