|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Ultrafine-grained and Heterostructured Materials (UFGH XII)
||High-strength Gradient-microstructure Steels by Additive Manufacturing
||Wenqi Liu, Zaiqing Que, Roy Björkstrand, Mika Salmi, Jouni Partanen, Junhe Lian
|On-Site Speaker (Planned)
This study proves the possibility of producing the heterogeneously gradient structure by additive manufacturing (AM), which benefits to simultaneously improved strength and ductility. The laser powder bed fusion technique with rotation scanning strategy is employed for high-strength steel in this study. With the same process parameters and specimen dimensions, a block stacked along the transverse direction (TD) performs a multiscale gradient structure instead of the typical AM melting pool structure in a building direction (BD) stacked block. The hierarchical electron backscatter diffraction is developed to investigate the hierarchical microstructure heterogeneity regarding phase, grain, and sub-grain morphology. The in-situ tension coupling micro-computed tomography is employed to observe porosity evolution. A hypothesis on the intrinsic thermal field during production is proposed to correlate process, microstructure, and plasticity. Consequently, gradient structures in TD samples significantly contribute to its high strength of 1200 MPa with the ductility of averagely 34% longer than BD ones.
||Additive Manufacturing, Mechanical Properties, Iron and Steel