|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||High Entropy Alloys IV
||Phase Decomposition of a Single-phase Nanocrystalline CoCrFeMnNi High-entropy Alloy
||Benjamin Schuh, Francisca Mendez-Martin, Bernhard Völker, Easo P. George, Helmut Clemens, Reinhard Pippan, Anton Hohenwarter
|On-Site Speaker (Planned)
An equiatomic CoCrFeMnNi high-entropy alloy was subjected to severe plastic deformation using high-pressure torsion. After this process the alloy remained a true FCC solid solution down to atomic scales with a grain size of ~50 nm leading to an increase in tensile strength to 1950 MPa and hardness of ~520 HV. Isochronal (1 hour) anneals led to a hardness increase with a maximum hardness of ~630 HV at about 450 °C before softening set in at higher temperatures. Isothermal anneals at 450°C revealed a hardness rise to a maximum of about 910 HV after 100 hours. This unexpected annealing response was correlated with decomposition of the solid solution into a nanocomposite structure consisting of four different phases using transmission electron microscopy and 3-dimensional atom probe tomography. Tensile tests revealed severe embrittlement due to the phase decomposition. Our results give new valuable insights into the phase stability of single-phase high-entropy alloys.
||Planned: A print-only volume