Decoupled magnetic tuning and hardness stability during spinodal decomposition in an Al-Cr-Fe-V high-entropy alloy
Materials Characterization, cilt.239, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 239
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.matchar.2026.116744
- Dergi Adı: Materials Characterization
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, Compendex, INSPEC, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
- Anahtar Kelimeler: Hardness stability, High-entropy alloys, Magnetic properties, Soft magnetic materials, Spinodal decomposition
- Orta Doğu Teknik Üniversitesi Adresli: Evet
Özet
A novel Al25Cr25Fe30V20 high-entropy alloy was designed using CALPHAD to undergo spinodal decomposition and produced by arc melting. The as-cast structure exhibits featureless homogenous equiaxed grains and body-centered cubic (BCC) structure. After a series of heat treatments from 2 to 12 h, SEM, TEM, and EDS analysis showed the alloy decomposed spinodally into a nanoscale network of two phases: a Fe- and an Al/Cr-rich phase, with a compositional difference of 14.1 at. % Fe. This chemical separation first switched the magnetic behavior of the alloy from paramagnetic to ferromagnetic. Subsequently, it significantly increased the saturation magnetization (σs) from 0.30 emu/g (2 h-annealed) to 0.59 emu/g (12 h-annealed). At the same time, the coercivity dropped from 82.7 Oe (2 h-annealed) to 61.4 Oe (12 h-annealed), indicating that coarsening of the network reduced the interfacial pinning sites and improved domain wall movement. Remarkably, this nanoscale chemical separation, which is confirmed by STEM-EDS mapping, had little effect on bulk mechanical properties. The microhardness (∼470 HV) and elastic modulus (∼220 GPa) remained consistent across all annealing conditions. This strong hardness stability is attributed to solid solution strengthening of the multicomponent matrix and the strengthening effect of the B2 ordered superlattice, which is confirmed via bulk XRD superlattice reflections. These findings demonstrate a new pathway for designing alloys without losing their mechanical integrity while being able to activate and tune the magnetic response of the material.