Entropy tailoring of thermodynamic behaviors and magnetocaloric effects in (GdTbDy)CoAl metallic glasses

• Published in: Materials & design Vol. 238; p. 112653
• Main Authors: Jin, Fan, Yuan, Chenchen, Pang, Changmeng, Wang, Xinming, Cao, Chengrong, Huo, Juntao
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.02.2024; Elsevier
• Subjects: Configurational entropy; Magnetocaloric effects; Metallic glasses; Thermodynamic behaviors; Thermodynamic behaviors; Metallic glasses; Magnetocaloric effects; Configurational entropy
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2024.112653

The kinetic behaviors and magnetocaloric properties of LE, ME, and HE MGs. [Display omitted] •(GdTbDy)CoAl metallic glasses (MGs) with low-, medium-, and high-entropy (HE) and critical diameters of more than 5 mm were fabricated.•The high configuration entropy could promote atomic motion, leading to the reduction of viscosity and deterioration of glass-forming ability.•The notable ordered structure in HE MGs slightly decreases activation energies for glass transition and crystal growth.•The high structural order, spin glass behaviors, and complicated compositions comprehensively contribute to outstanding magnetocaloric effects. The effect of configuration entropy (ΔSconf) on thermal properties and magnetocaloric effects (MCE) of metallic glasses (MGs) remains vague. In this work, Tb55Co17.5Al27.5 low-, (Gd0.5Tb0.5)55Co17.5Al27.5 medium-, and (Gd1/3Tb1/3Dy1/3)55Co17.5Al27.5 high-entropy (LE, ME, and HE) MGs with critical diameters more than 5 mm were successfully fabricated. Systematic investigations into their thermodynamic behaviors suggest that high ΔSconf might deteriorate glass forming ability (GFA) along with reduced viscosity. Simultaneously, an improved thermal stability was observed in ME and HE MGs for their high activation energies for glass transition, crystal nucleation and growth, while the notable ordered structure in HE MG could accelerate glass transition and crystal growth by reducing activation energies. Studies of MCE indicate that the distinguished spin glass behaviors and higher structural order in HE MGs comprehensively contribute to an enhanced relative cooling power and a broader magnetic-transition temperature range, whereas the change of Curie temperature and maximum magnetic entropy more depends on the de Gennes factor rather than ΔSconf. All three designed MGs manifesting the competitive GFA and MCE could be candidates for magnetic refrigeration. Our studies show that entropy tailoring seems to play a dominant role in determining thermodynamic behaviors, which could help to design more stable MCE MGs.