Hot deformation behavior of Hastelloy-X preforms built using directed energy deposition based laser additive manufacturing

摘要

Hastelloy-X (Hast-X) preforms built using Laser Directed Energy Deposition (LDED) are investigated for hot workability using hot deformation tests (temperature: 1223-1373 K, strain rate: 0.01-10 s(-1)). Strain hardening is observed at lower strain due to dislocation pileup and flow softening is observed at higher strain. Cyclic strain rate jump test and jump temperature tests are performed to calculate strain sensitivity factor and activation energy (Q), respectively. The derived constitutive equations are found to be in good agreement with experimental results with maximum deviation of 20%. Average Q value is found to be 280 kJ.mol(-1), which is lower than that for similar alloys in wrought condition. The lower 'Q' value confirms the suitability of hot working of LDED built Hast-X as a potential method to build high strength engineering components. (C) 2020 Elsevier B.V. All rights reserved.