A. Thomas

Bio: A. Thomas is an academic researcher from Polytechnic University of Catalonia. The author has contributed to research in topics: Superalloy & Inconel. The author has an hindex of 1, co-authored 1 publications receiving 300 citations.

Hot deformation behavior and processing map of a typical Ni-based superalloy

Abstract: The hot compressive deformation behaviors of a typical Ni-based superalloy are investigated over wide ranges of forming temperature and strain rate. Based on the experimental data, the efficiencies of power dissipation and instability parameters are evaluated and processing maps are developed to optimize the hot working processing. The microstructures of the studied Ni-based superalloy are analyzed to correlate with the processing maps. It can be found that the flow stress is sensitive to the forming temperature and strain rate. With the increase of forming temperature or the decrease of strain rate, the flow stress significantly decreases. The changes of instability domains may be related to the adiabatic shear bands and the evolution of δ phase(Ni 3 Nb) during the hot formation. Three optimum hot deformation domains for different forming processes (ingot cogging, conventional die forging and isothermal die forging) are identified, which are validated by the microstructural features and adiabatic shear bands. The optimum window for the ingot cogging processing is identified as the temperature range of 1010–1040 °C and strain rate range of 0.1–1 s −1 . The temperature range of 980–1040 °C and strain rate range of 0.01–0.1 s −1 can be selected for the conventional die forging. Additionally, the optimum hot working domain for the isothermal die forging is 1010–1040 °C and near/below 0.001 s −1 .

Flow behavior and microstructures of superalloy 718 during high temperature deformation

Abstract: Flow behavior and microstructures of superalloy 718 were investigated by hot compression tests performed at temperatures ranging from 950 to 1100 °C with strain rates of 10−3 to 1 s−1. The dependence of the peak stress on deformation temperature and strain rate can be expressed by a hyperbolic-sine type equation. The activation energy for superalloy 718 is determined to be 443.2 kJ mol−1. A power exponent relationship between the peak strain and the Z parameter is obtained. Microstructure analysis shows that the dynamically recrystallized grain size is inversely proportional to the Z parameter. The nucleation mechanisms of DRX are closely related to the value of Z parameter. Under low Z conditions, DRX nucleation and development are mainly assisted by the formation of twins near the original grain boundaries.

Review on powder-bed laser additive manufacturing of Inconel 718 parts

Abstract: This study presents a thorough literature review on the powder-bed laser additive manufacturing processes such as selective laser melting of Inconel 718 parts. This article first introduces the gen...