|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Ultrafine-grained and Heterostructured Materials (UFGH XII)
||Severely Deformed Stainless Steel Reveals an Anomaly in Thermal Expansion Behavior
||Oliver Renk, Robert Enzinger, Christoph Gammer, Daniel Scheiber, Wolfgang Sprengel, Reinhard Pippan, Jürgen Eckert, Lorenz Romaner, Andrei Ruban
|On-Site Speaker (Planned)
The large densities of lattice defects in severely deformed metals can alter the thermal expansion behavior. Upon annihilation, the excess volume associated with them generally reduces the global thermal expansion compared to the defect-scarce reference sample. Here we report on the striking observation that a severely deformed austenitic steel expands more than its defect-scare reference. We will show that this yet unknown thermal expansion behavior is induced by the exceptionally high density of stacking faults (1.8 nm average spacing), inducing a fcc to hcp transition at the atomic scale. Due to the peculiar magnetic structure of the austenitic steel, longitudinal spin fluctuations induce a pronouncedly different expansion behavior of the fcc and hcp phase, provoking a strong thermal expansion normal to the fault plane. Other severely deformed samples with similar stacking fault density but where fcc and hcp phase expand similarly do not show the anomalous expansion, supporting this conclusion.
||Computational Materials Science & Engineering,