Elasticity of single crystal tungsten up to 11 GPa

Compressional (P) and shear (S) wave velocities of tungsten along the [100] and [110] directions were measured using ultrasonic interferometry up to 11.3 GPa in a multi-anvil apparatus. Benchtop measurements at ambient conditions yielded Vp=5.27(2) km/s and Vs=2.91(1) km/s. A global non-linear least-square fit of Vp^[100], VS^[100], and Vp^[110] was used to derive the elastic constants Cij via the relationships: C₁₁=ρ(Vp^[100])², C₄₄=ρ(Vs^[100])² and C₁₁+2C₄₄+C12=ρ(Vp^[110])². Our results show comparable values of derived elastic constants with previous low-pressure (up to 0.5 GPa) ultrasonic studies on tungsten single crystals, while previous density functional theory (DFT) calculations tend to underestimate . The elastic anisotropy increases slightly from 1.01 to 1.03 up to 11.3 GPa, indicating that tungsten remains nearly isotropic under compression. Mechanical property analyses, including Pugh’s and Pettifor’s modulus ratios, suggest that tungsten is weakly ductile, with ductility increasing slightly under pressure.