Phase stability and compressive properties of low-density (Zr50Ti35Nb15)100-xAlx high entropy alloys. (September 2022)

• Record Type: Journal Article
• Authors: Gao, K.; Wang, J.Z.; Meng, Y.H.; Li, Y.; Zhang, Y.
• Is Part Of: Intermetallics. Volume 148(2022)
• Publication Date: 2022-09
• Subjects: High entropy alloys -- Phase stability -- B2 structure -- Compressive properties; Intermetallic compounds -- Metallography -- Periodicals; Metallic glasses -- Periodicals; Composés intermétalliques -- Métallographie -- Périodiques; 669.94
• DOI: 10.1016/j.intermet.2022.107622
• Languages: English
• ISSNs: 0966-9795

Abstract

Abstract: In the present study, phase stability and compressive mechanical properties of the (Zr50 Ti35 Nb15 )100-x Alx (x = 0 to 30 at.%) high-entropy alloys were investigated. It was found that the crystalline structure of cast alloys changed from the initial disordered body-centered cubic (BCC) structure to an ordered body-centered cubic (B2) structure as the Al concentration was increased. Their microstructure and phase evolution after long-term annealing up to 1000 h at temperature ranging from 900 °C to 1100 °C were analyzed. Annealing has no obvious influence on the matrix phase of Zr50 Ti35 Nb15, which keeps BCC structure during all the annealing processes. For the alloys (Zr50 Ti35 Nb15 )80 Al20 and (Zr50 Ti35 Nb15 )70 Al30 with higher Al content, secondary phase (Al3 Zr5 ) precipitates after annealing at 900 °C. With the increasing annealing temperature to 1000 °C or 1100 °C，there is a tendency that the amount of the Al3 Zr5 phase decreases slightly, indicating that Al3 Zr5 phase is unstable at high temperature. Accompanied by the phase change, there were also corresponding variations in compressive properties. The secondary phase precipitated in the (Zr50 Ti35 Nb15 )80 Al20 and (Zr50 Ti35 Nb15 )70 Al30 decreases the compressive plasticity, but has little influence on the yield strength. Meanwhile, the compressive properties of as-cast (Zr50 Ti35 Nb15 )90 Al10 and (Zr50 Ti35 Nb15 )85 Al15 were also tested to investigate the effect of Al content on the yield strength. Our findings provide a new insight in developing low-density high entropy alloys containing Al. Highlights: Low-density high entropy alloys with higher Al content were investigated. Phase stability at high temperature of 900–1100 °C was investigated. The secondary phase is detrimental to the compressive plasticity, but has little effect on the yield strength. Solid solution strengthening plays an important role in increasing the strength.