Fig. 3: Correlation of bulk modulus with TBOD in 13 HEAs.
From: Fundamental electronic structure and multiatomic bonding in 13 biocompatible high-entropy alloys

Dashed line is a linear fit that resulted from the coefficient of determination R2 = 0.70 of bulk modulus (K) in GPA and TBOD in e/Å of the 13 investigated HEAs. This means the K is tightly correlated with TBOD.