• Nili-Ahmadabadi, Mahmoud
• Shahmir, Hamed
• Andrzejczuk, Mariusz
• Langdon, Terence G.
• Lewandowska, Małgorzata
• Shafiee, Ahad

Abstract

A CoCrFeNiMnTi0.1 high-entropy alloy (HEA) was processed by high-pressure torsion (HPT) followed by postdeformationannealing (PDA) at 200–900 °C. Microstructural evaluations revealed that the initial and HPTprocessedmicrostructures consisted of a single fcc phase and there was no evidence for decomposition duringsevere plastic deformation. However, PDA at temperatures below 900 °C promoted the formation of a multiphasemicrostructure containing new precipitates and significant grain coarsening occurred after PDAat> 800 °C due to a dissolution of the precipitates. PDA at 800 °C for 60 min led to very good mechanicalproperties with an ultimate tensile strength (UTS) and elongation to failure of> 1000 MPa and ~ 40%, respectively.The results demonstrate that the minor addition of Ti to the CoCrFeNiMn alloy has no direct effect onthe strengthening mechanisms but nevertheless this addition significantly increases the thermal stability of theprecipitates and these precipitates are effective in minimizing grain coarsening. Therefore, the Ti addition plays an important role in strengthening the HEA.

Topics

• polymer
• grain
• phase
• strength
• precipitate
• annealing
• tensile strength
• decomposition
• phase stability