Stony Brook Researchers Examine Corrosion Behavior of 3D Printed Steel

A multi-modal investigation of additively manufactured 316L stainless steel revealing a heterogeneous—and correlative—distribution of crystal defects in the bright-field transmission electron micrograph (grey-scale) and alloying elements in the superimposed x-ray fluorescence map (colored). Image courtesy of Dr. W. Streit Cunningham and Prof. Jason Trelewicz, Stony Brook University.

A new study led by researchers from Stony Brook University (Stony Brook, New York, USA) examines the connections between the corrosion behavior and underlying materials structure in laser additively manufactured 316L stainless steel, a corrosion resistant metal used widely in Naval applications. This steel is manufactured using laser additive manufacturing, a form of 3D printing that builds up parts layer-by-layer by melting and resolidifying metal powders.

In the study published in the November issue of Additive Manufacturing, the uses multimodal synchrotron X-ray techniques to uncover new connections between printing parameters and the defect state in the material. Exploring these connections can enable researchers to map pathways for developing an improved corrosion resistant printed alloy by engineering its defects at the nanoscale. The research also demonstrated that multimodal synchrotron techniques help to establish correlations between the printing process, the underlying structure of the material, and its realized performance.

“The major focus of our study was to understand the corrosion behavior of laser additively manufactured 316L stainless steel in the context of microstructural defects that form due to the rapid solidification rates inherent to this 3D printing process,” explains Jason Trelewicz, the study’s corresponding author and associate professor of materials science and engineering in the College of Engineering and Applied Sciences and the Institute for Advanced Computational Science. “We show that while uniform surface corrosion of the printed 316L is similar to a traditional 316L alloy, the printed material exhibits an increased susceptibility to pitting, particularly in the samples with the greatest defect density uncovered from our synchrotron measurements.”

The team consisted of research scientists and students in Trelewicz’s group, the Engineered Microstructures and Radiation Effects Laboratory, working with collaborators at Brookhaven National Laboratory (Upton, New York, USA). They conducted their synchrotron X-ray experiments at Brookhaven’s National Synchrotron Light Source II, and 316L samples were printed at Penn State University (Centre County, Pennsylvania, USA). The team performed correlative electron microscopy at the Center for Functional Nanomaterials at Brookhaven and corrosion measurements were performed at Stony Brook University.

Beyond the development of novel additively manufactured materials, Trelewicz says the findings highlight the critical role correlative synchrotron X-ray and electron microscopy measurements can play in building a detailed picture of volume-averaged microstructural trends in materials developed by laser additive manufacturing.

Source: Stony Brook University News,