Constitutive modeling of hot deformation behavior of vacuum hot pressed Cu–8Cr–4Nb alloy. (15th June 2015)

• Record Type: Journal Article
• Authors: Shukla, A.K.; Narayana Murty, S.V.S.; Sharma, S.C.; Mondal, K.
• Is Part Of: Materials & design. Volume 75(2015:Nov.)
• Page Start: 57
• Page End: 64
• Publication Date: 2015-06-15
• Subjects: Hot pressing -- Dispersion hardening -- Hot deformation -- Constitutive modeling -- Activation energy; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2015.03.023
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract : Graphical abstract: Highlights: Isothermal hot compression behavior of vacuum hot pressed Cu–8Cr–4Nb is reported for the first time. Cu–8Cr–4Nb alloy was isothermally hot compressed in the temperature range of 800–950 °C and strain rate range of 0.01–10 s −1 . Constitutive model for hot-deformation of Cu–8Cr–4Nb was successfully developed. The activation energy for hot deformation of Cu–Cr–Nb alloy was calculated to be 436.89 kJ/mol. The high activation energy was attributed to presence of fine Cr2 Nb precipitates. Abstract: In the present study, atomized Cu–8Cr–4Nb alloy powder having in-situ formed Cr2 Nb precipitates was vacuum hot pressed to near theoretical density. The hot-pressed alloy was hot isothermally compression tested at temperatures of 800 °C, 850 °C, 900 °C and 950 °C and strain rates of 0.01 s −1, 0.1 s −1, 1 s −1 and 10 s −1 to study the deformation behavior. The effect of friction between sample and compression die was evaluated and was found to be quite low. The measured flow stress data was used for the development of constitutive model for hot deformation behavior Cu–8Cr–4Nb alloy. The activation energy for hot deformation of hot-pressed Cu–8Cr–4Nb alloy was calculated to be 436.89 kJ/mol, which is significantly higher than that of the pure copper. The higher activation energy is attributed to the presence of Cr2 Nb precipitates which are expected to generate threshold stress and reduce the effective stress available for thermal deformation.