Effect of Cr and Zr on phase stability of refractory Al-Cr-Nb-Ti-V-Zr high-entropy alloys

JOURNAL OF ALLOYS AND COMPOUNDS

卷:757

Article

Yurchenko, N. Yu.¹  Stepanov, N. D.¹  Gridneva, A. O.¹  Mishunin, M. V.²  Salishchev, G. A.¹  Zherebtsov, S. V.¹ 

[1] Belgorod State Natl Res Univ, Lab Bulk Nanostruct Mat, Belgorod 308015, Russia

[2] Belgorod State Natl Res Univ, Lab Radiat Phys, Belgorod 308015, Russia

关键词: High entropy alloys;    Microstructure;    Phase transitions;    Mechanical properties;    Scanning electron microscopy;    SEM;    Transmission electron microscopy;    TEM;   

DOI  :  10.1016/j.jallcom.2018.05.099

来源: Elsevier

【 摘 要 】

The effect of annealing at 800 degrees C or 1000 degrees C for 100 h on the structure and mechanical properties of refractory AlCrxNbTiV and AlNbTiVZrx (x = 0-1.5) high-entropy alloys was studied. In the initial condition (annealing at 1200 degrees C for 24 h), the AlNbTiV and AlCn(0.5)NbTiV alloys were composed of the B2 phase while the AlCrNbTiV and AlCr1.5NbTiV alloys had a mixture of the B2 and Cr2Nb-type C14 Laves phases. The AlNbTiVZrx (x = 0.5-1.5) alloys in the initial condition consisted of the B2, Zr5Al3-type, and ZrAlV-type C14 Laves phases. Annealing of the AlCrxNbTiV (x = 0-1.5) alloys at 800 degrees C or 1000 degrees C resulted in (i) precipitation of the Nb2Al-type alpha-phase or an increase in the fraction of the Laves phase; (ii) an increase in the microhardness and a pronounced drop in ductility. Annealings of the AlNbTiVZrx (x = 0.5-1.5) alloys at 800 degrees C or 1000 degrees C led to insignificant changes in the structure and microhardness but somewhat decreased ductility. Quasi-binary AlNbTiV-Cr and AlNbTiV-Zr phase diagrams constructed with a Thermo-Calc software and TCHEA2 database were used to analyze phase transformations in the experimental alloys. The differences in the behavior of the Cr/Zr-containing alloys and the relationships between the phase composition and mechanical properties of the alloys were discussed. (C) 2018 Elsevier B.V. All rights reserved.

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