The effect of temperature on the high-strain-rate response of Co-Al-W- base alloys: Experiments and modeling

Two novels Powder Metallurgy (PM) cobalt-based superalloys with a γ/γ’ dual-phase microstructure have been subjected to dynamic uniaxial compression tests at temperatures from 25 °C to 850 °C, and a high strain rate of 2500 s−1, to investigate the effect of temperature on their high-strain-rate resp...

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Bibliographic Details
Published in:Journal of alloys and compounds 2022-03, Vol.897, p.163154, Article 163154
Main Authors: Casas, Rafael, Sancho, Rafael, Campos, Mónica, Gálvez, Francisco
Format: Article
Language:English
Subjects:
Aluminum
Anomalies
Cobalt base alloys
Cobalt-base superalloys
Compression tests
Constitutive model
Constitutive models
Finite element method
Heat resistant alloys
Heat treating
High strain rate
High temperature
Hopkinson-bar
Mathematical models
Powder metallurgy
Split Hopkinson pressure bars
Strain rate sensitivity
Superalloys
Temperature
Temperature dependence
Temperature effects
Yield strength
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Summary:Two novels Powder Metallurgy (PM) cobalt-based superalloys with a γ/γ’ dual-phase microstructure have been subjected to dynamic uniaxial compression tests at temperatures from 25 °C to 850 °C, and a high strain rate of 2500 s−1, to investigate the effect of temperature on their high-strain-rate response. Compression tests have been performed using a Split Hopkinson Pressure Bar (SHPB), focusing on the temperature-dependent anomalies of the flow stress at high temperatures for both alloys. The analysis of the experimental results indicates an important strain-rate sensitivity and thermal softening effect with a noticeable positive stress peak at high temperatures. Finally, a Johnson-Cook-type constitutive model is developed to describe the flow stress as a function of the temperature, including the anomalous positive peak temperature. The modified JC model presents a good correlation to predict the behavior of both Co-based superalloys over wide ranges of temperatures through simulating the experimental camping with Abaqus. This model offers a potential instrument to simulate and optimize high impact events applications. [Display omitted] •The effect of temperature on the dynamic flow stress of two Cobalt based superalloys, processed by Powder Metallurgy (PM) route, was investigated and modelled.•Both alloys showed a positive temperature dependence of the yield strength above 600 °C.•The addition of alloying elements (Ti and Ta) shifted to 800°C the peak flow stress and improved the performance above 700 °C.•A constitutive model was developed to describe the flow stress as a function of the temperature.
ISSN:0925-8388
1873-4669
DOI:10.1016/j.jallcom.2021.163154