March 2018

 
CAMECA Calendar Competition Winning Image: Nanoscale phase separation in an AlCoCrFeNi high entropy alloy by Atom Probe Tomography
Nanoscale phase separation in an AlCoCrFeNi high entropy alloy by Atom Probe Tomography
High entropy alloys (HEAs) typically consist of five or more elements in nearly equal proportions. It is hypothesized that the large configurational entropy favors the formation of simple crystalline solid solutions. In reality, however, HEAs can undergo phase transformations such as precipitation, ordering, and spinodal decomposition. These nanoscale microstructural heterogeneities have a profound influence on the alloy’s properties. Using APT, NRL researchers investigated an Al0.5CoCrFeNi HEA, which spinodally decomposes into a disordered body-centered cubic (BCC) phase enriched in Cr, Fe,Co and an ordered BCC (B2) phase that is rich in Ni and Al.

Study was performed on a CAMECA LEAP 4000X Si.

Image was submitted by Keith Knipling, U.S. Naval Research Laboratory.

K. E. Knipling, J. L. Tharpe, and P. K. Liaw. Nanoscale Phase Separation in Al0.5CoCrFeNi(Cu) High Entropy Alloys as Studied by Atom Probe Tomography. Microscopy and Microanalysis, 23(S1), 726-727 (2017).