The correlations between tensile properties and some common parameters in BCC refractory multi-principal element alloys (RMPEAs) have been systematically investigated. The findings can be used as guidelines for the alloy design. We found that there exists a positive linear correlation between average atomic shear modulus mismatch and yield strength, and more negative enthalpy of mixing is peculiarly prone to brittle fracture in RMPEAs. Meanwhile, some BCC RMPEAs with first-class tensile properties were designed successfully. The analyses of alloys’ toughen mechanism revealed that their high strength, as well as good ductility, is attributed to lattice distortion and dislocation glide respectively. GRAPHICAL ABSTRACT IMPACT STATEMENT This work provided some effective guidelines for the design of BCC refractory multi-principal element alloys with superior strength-ductility combinations via utilizing several common physical parameters.

Two-body abrasive wear tests of Fe-B alloys with various matrix microstructures were performed using a pin-on-disc tribometer at a normal load of 3 N. The wear behavior was analyzed using scanning electron microscopy (SEM) and color 3D laser scanning microscopy. The results show that the Fe–2 wt% B alloy is mainly composed of a metallic matrix, M₂B and M₂₃(C, B)₆. A pure pearlitic matrix occurs at a cooling rate of 0.05 °C/s, and a pure martensitic matrix forms at a cooling rate above 0.3 °C/s. Compared to the pearlitic matrix, the martensitic matrix can better support the M₂B against fracture and provides higher abrasion resistance for the Fe–2 wt% B alloy. Moreover, with an increase in sliding distance, the abrasion resistance of Fe–2 wt% B alloy decreases slightly at first and then decreases rapidly. To be exact, the M₂B is steadily scraped off until the critical sliding distance of 6.06 m is reached, after which the neighboring M₂B fractures, leading to high material removal.