Mechanical properties of pure elements from a comprehensive first-principles study to data-driven insights

Abstract

Unraveling mechanical properties from fundamental is far from complete despite their vital role in determining applicability and longevity for a given material. Here, we perform a comprehensive study related to mechanical properties of 60 pure elements in bcc, fcc, hcp, and/or diamond structures by means of pure alias shear and pure tensile deformations via density functional theory (DFT) based calculations alongside a broad review of existing literature. The present data compilation enables a detailed correlation analysis of mechanical properties, focusing on DFT-based ideal shear and tensile strengths (${\tau }_{\text{is}}$ and ${\sigma }_{\text{it}}$), stable and unstable stacking fault energies (${\gamma }_{\text{sf}}$ and ${\gamma }_{\text{us}}$), surface energy (${\gamma }_s$), and vacancy activation energy ($Q_V$); and experimental hardness ($H_B$), ultimate tensile strength (${\sigma }_{\text{UT}}$), fracture toughness ($K_{\text{Ic}}$), and elongation (${\epsilon }_{\text{EL}}$). The present work examines models, identifies outliers, and provides insights into mechanical properties, for example, (i) $H_B$ is correlated by $Q_V$, ${\sigma }_{\text{UT}}$ by $\sqrt{{\gamma }_s}$ or $\sqrt{{\gamma }_{\text{us}}}$, and $K_{\text{Ic}}$ by ${\gamma }_s$; (ii) data outliers are identified for Cr (related to ${\tau }_{\text{is}}$, ${\gamma }_s$, $Q_V$, and ${\sigma }_{\text{UT}}$), Be (${\tau }_{\text{is}}$, ${\gamma }_{\text{sf}}$, ${\gamma }_{\text{us}}$, and $Q_V$), Hf ($H_B$ and $K_{\text{Ic}}$), Yb (all properties), and Pt (${\gamma }_{\text{sf}}$ vs. ${\gamma }_{\text{us}}$); and (iii) ${\tau }_{\text{is}}$, ${\sigma }_{\text{it}}$, ${\gamma }_{\text{sf}}$, ${\gamma }_{\text{us}}$, ${\gamma }_s$, $Q_V$, and $H_B$ are highly correlated to elemental attributes, while ${\sigma }_{\text{UT}}$, $K_{\text{Ic}}$, and especially ${\epsilon }_{\text{EL}}$ are less correlated due mainly to experimental uncertainty. In particular, the present data compilation provides a solid foundation to model properties such as ${\gamma }_s$ and ${\tau }_{\text{is}}$ of multicomponent alloys and ${\tau }_{\text{is}}$ of unstable structures like bcc Ti, Zr, and Hf.