About this Abstract |
Meeting |
MS&T22: Materials Science & Technology
|
Symposium
|
Additive Manufacturing of Metals: Microstructure, Properties and Alloy Development
|
Presentation Title |
Exceptional Ductility Induced by The Intrinsic Grain Boundary Engineering |
Author(s) |
Lin Gao, Wenhao Lin, Zhongshu Ren, Ma Ji, Tao Sun |
On-Site Speaker (Planned) |
Lin Gao |
Abstract Scope |
Developing effective strategies to fabricate structural materials with superior mechanical performance is attractive in metal additive manufacturing (AM). We applied a wiggle deposition pattern in wire laser directed energy deposition of 316L stainless steel, which enables the grain boundary (GB) engineering during the solidification process. The as-deposited sample exhibits exceptional ductility without compromise of strength. Through multi-physics simulation and operando near-infrared imaging, we discover that the wiggle deposition induces highly dynamic melt flow and oscillating thermal gradient in the melt pool, which are responsible for the generation of GB protrusions consisting of multiple subgrains. This unique microstructure is found to promote intergranular deformation, therefore improving the tensile properties of the sample. We believe the fundamental principle of tailoring GB structures via perturbing the solidification can be readily implemented in other metal AM processes involving high-energy-density heat sources to further push the classical strength–ductility envelope of conventional and emerging alloys. |