Enhanced high-temperature strength of HfNbTaTiZrV refractory high-entropy alloy via Al2O3 reinforcement. (1st October 2022)

• Record Type: Journal Article
• Authors: Wang, Bingjie; Wang, Qianqian; Lu, Nan; Liang, Xiubing; Shen, Baolong
• Is Part Of: Journal of materials science & technology. Volume 123(2022)
• Page Start: 191
• Page End: 200
• Publication Date: 2022-10-01
• Subjects: Al2O3-reinforcement -- HfNbTaTiZrV -- Refractory high-entropy alloy -- Interstitial strengthening; Metals -- Periodicals; Materials science -- Periodicals; Materials science; Metals; Periodicals; 620.1105
• DOI: 10.1016/j.jmst.2022.01.025
• Languages: English
• ISSNs: 1005-0302

Abstract

Highlights: Oxide dispersion-reinforced HfNbTaTiZrV alloy with multiple strengthening mechanisms is fabricated by the addition of Al2 O3 oxide. Nanoscale Al2 O3 particles hinder the movement of dislocations and refine the grains from 80 to 13 μm. The interstitial strengthening improves the high temperature softening resistance of the studied alloy. 4 vol.%Al2 O3 -reinforced alloy displays superior compressive yield strength of 1392 MPa at 800 °C and 693 MPa at 1000 °C. 4 vol.%Al2 O3 alloy displays notable characteristics of lightweight and high-temperature resistance. Abstract: Novel composites of HfNbTaTiZrV refractory high-entropy alloy (RHEA) reinforced with 0–4 vol.% Al2 O3 particles have been synthesized by vacuum arc melting. The microstructure evolution, compressive mechanical properties at room and elevated temperatures, as well as strengthening mechanism of the composites were analyzed. The HfNbTaTiZrV RHEA reinforced with 4 vol.% Al2 O3 displayed excellent phase stability at elevated temperatures. A superior compressive yield strength of 2700 MPa at room temperature, 1392 MPa at 800 °C, and 693 MPa at 1000 °C was obtained for this composite. The improved yield strength resulted from multiple strengthening mechanisms caused by Al2 O3 addition, including solution strengthening, interstitial strengthening, grain boundary strengthening, and dispersion strengthening. Besides, the effects of interstitial strengthening increased with temperature and was the main strengthening mechanism at elevated temperatures. These findings not only promote the development of oxide-reinforced RHEAs for challenging engineering applications but also provide guidelines for the design of light refractory materials with multiple strengthening mechanisms.