Overcoming the strength-ductility trade-off in refractory medium-entropy alloys via controlled B2 ordering

Herein, we showed that controlled additions of Al, which provided a certain degree of B2 ordering, resulted in a similar to 37%-enhancement of both yield strength and uniform elongation in Al-x(NbTiZr)(100-x) (x = 0; 2.5; 5; 7.5 at.%) refractory medium-entropy alloys. The improvement of properties stemmed from the solid solution and short-range order strengthening, as well as from the alteration in a character of dislocation glide. The B2 ordering caused the formation of multiple dislocation bands and the activation of cross-slip, which improved the macroscopic stability of plastic flow and extended the strengthening stage, thereby postponing necking. IMPACT STATEMENT Controlled Al-induced B2 ordering helps overcome the strength-ductility dilemma in refractory medium-entropy alloys due to solid solution and short-range strengthening coupled with the dislocation motion changing.

Automated summary

Controlled Al-induced B2 ordering helps overcome the strength-ductility dilemma in refractory medium-entropy alloys due to solid solution and short-range strengthening coupled with the dislocation motion changing.