https://dc.engconfintl.org/cgi/viewcontent.cgi?article=1032&context=superalloys_ii

A critical review of high entropy alloys and related concepts

High-entropy alloys (HEAs) are alloys with five or more principal elements. Due to the distinct design concept, these alloys often exhibit unusual properties. Thus, there has been significant interest in these materials, leading to an emerging yet exciting new field. This paper briefly reviews some critical aspects of HEAs, including core effects, phases and crystal structures, mechanical properties, high-temperature properties, structural stabilities, and corrosion behaviors. Current challenges and important future directions are also pointed out.

https://www.tandfonline.com/doi/pdf/10.1080/21663831.2014.912690

High-Entropy Alloys: A Critical Review

Phase stability is an important topic for high entropy alloys (HEAs), but the understanding to it is very limited. The capability to predict phase stability from fundamental properties of constituent elements would benefit the alloy design greatly. The relationship between phase stability and physicochemical/thermodynamic properties of alloying components in HEAs was studied systematically. The mixing enthalpy is found to be the key factor controlling the formation of solid solutions or compounds. The stability of fcc and bcc solid solutions is well delineated by the valance electron concentration (VEC). The revealing of the effect of the VEC on the phase stability is vitally important for alloy design and for controlling the mechanical behavior of HEAs.

/pdf/effect-of-valence-electron-concentration-on-stability-of-fcc-3bvc8oeb0w.pdf

Effect of valence electron concentration on stability of fcc or bcc phase in high entropy alloys

Sluggish diffusion in Co-Cr-Fe-Mn-Ni high-entropy alloys

/pdf/phase-stability-in-high-entropy-alloys-formation-of-solid-54ci0ongt4.pdf

Phase stability in high entropy alloys: Formation of solid-solution phase or amorphous phase

Effect of aging temperature on microstructure and properties of AlCoCrCuFeNi high-entropy alloy

Characterization of hot deformation behavior of a new near beta titanium alloy: Ti-7333

Deformation and dynamic recrystallization behavior of a high Nb containing TiAl alloy

Transmission Electron Microscope (TEM) and Electron Backscattered Diffraction (EBSD) are employed to explore the influence of deformation conditions on microstructure and the deformation mechanism of a new near β titanium alloy Ti-7333 after hot compression tests which at temperatures ranging from 770 to 970 °C and strain rates ranging from 0.001 to 10 s −1 . The results showed that the effect of deformation parameters on microstructure evolution is significantly. Both increasing the temperature and decreasing the strain rate seem to promote the dynamic recrystallization process. The mechanism is dominated by dynamic recovery, globularization and dynamic recrystallization. The globularization trend of α phase is more remarkable deformed at higher temperature and lower strain rate. And reverse, the lower temperature and higher strain rate are more favorable to α phase refinement. The fraction of low-angle grain boundaries in the deformation microstructure decreases with the increasing of temperature and decreasing of strain rate. It illustrates the low-angle grain boundaries would turn to high-angle grain boundaries during deformation. The expression of the size of recrystallized grains D r and parameter Z is obtained by regression analysis as ln  D r =8.79964−0.33663ln  Z . All the deformed samples present strong 〈001〉 and weak 〈111〉 fiber texture. With the increasing of temperature and decreasing of strain rate, the 〈001〉 texture strengthens gradually and 〈111〉 texture weakens gradually until extinction.

Hui Chang

Papers

Effect of aging temperature on microstructure and properties of AlCoCrCuFeNi high-entropy alloy

Characterization of hot deformation behavior of a new near beta titanium alloy: Ti-7333

Deformation and dynamic recrystallization behavior of a high Nb containing TiAl alloy

Hot deformation mechanism and microstructure evolution of a new near β titanium alloy

Characterization of hot deformation behavior of Haynes230 by using processing maps