Effect of high-temperature exposure on the microstructure and mechanical properties of the Al5Ti5Co35Ni35Fe20 high-entropy alloy

Piotr Bała, Kamil Górecki, Wiktor Bednarczyk, Maria Wątroba, Sebastian Lech, Jakub Kawałko
2019 Journal of Materials Research and Technology  
j m a t e r r e s t e c h n o l . 2 0 2 0;9(1):551-559 w w w . j m r t . c o m . b r High entropy alloys Aging Microstructure ␥ Discontinuous precipitation a b s t r a c t Effect of high-temperature exposure on the microstructure and mechanical properties of the Al5Ti5Co35Ni35Fe20 High-Entropy Alloy was studied. High-entropy alloys belong to the group of multi-principal element alloys composed of at least five elements with a concentration between 5 and 35 atomic pct. Despite the multicomponent
more » ... the multicomponent composition, the goal is to achieve a simple solid solution. The alloy was exposed to a temperature range of 650-900 • C for 168 h (7 days), after hot rolling and air-quenching. After hot rolling the investigated alloy was not fully supersaturated. The application of air cooling caused ␥ precipitation, which was uniformly distributed within the microstructure. High-temperature exposure caused the growth of ␥ particles. At 700 • C and higher, additional continuous and discontinuous precipitation of ␥ was observed. Finally, the microstructure of the investigated alloy consisted of ␥ matrix and three types of ␥' precipitates, i.e. spherical ␥ phases with bimodal distribution within the grains and elongated DP ␥ phases present at the grain boundaries. The highest mechanical properties were obtained after exposure to 650 • C, which was caused by ␥ precipitation. Further increase in temperature decreased the mechanical properties.
doi:10.1016/j.jmrt.2019.10.084 fatcat:57lbijpydngm5lxswlfwonnnmy