Fig. 1: Crack initiation and propagation configurations comparing Nb, NbMoTaW, and Nb₄₅ Ta₂₅ Ti₁₅ Hf₁₅.

For a \(\{110\}\langle 1\bar{1}2\rangle\) crack orientation, atomic configurations from fracture simulations for Nb (a, b), NbMoTaW (c, d) and Nb₄₅Ta₂₅Ti₁₅Hf₁₅ (e, f), at different loadings represented by the values of K_I listed below each panel. Crack initiation events for an atomically sharp crack tip are provided in (a, c, e) and for later stages of crack propagation (b, d, f). The crack initiates by bond breaking in Nb and NbMoTaW, and by dislocation emission in Nb₄₅Ta₂₅Ti₁₅Hf₁₅. The crack initiates by bond breaking in Nb and NbMoTaW, and dislocation emissions in Nb₄₅Ta₂₅Ti₁₅Hf₁₅. While the fracture mode remained the same in Nb and Nb₄₅Ta₂₅Ti₁₅Hf₁₅, it displays dislocation emissions during some of the later stages in NbMoTaW. The atoms are colored by their structural types identified by the DXA algorithm⁴⁴ in Ovito⁴⁵: blue represents atoms in bcc environments and white represents atoms in defected environments.