Details

Autor(en) / Beteiligte

• Park, H-S
• Rudd, R E
• Cavallo, R M
• Barton, N R
• Arsenlis, A
• Belof, J L
• Blobaum, K J M
• El-dasher, B S
• Florando, J N
• Huntington, C M
• Maddox, B R
• May, M J
• Plechaty, C
• Prisbrey, S T
• Remington, B A
• Wallace, R J
• Wehrenberg, C E
• Wilson, M J
• Comley, A J
• Giraldez, E
• Nikroo, A
• Farrell, M
• Randall, G
• Gray, 3rd, G T

Titel

Grain-size-independent plastic flow at ultrahigh pressures and strain rates

Ist Teil von

• Physical review letters, 2015-02, Vol.114 (6), p.065502-065502, Article 065502

Ort / Verlag

United States: American Physical Society

Erscheinungsjahr

2015

Link zum Volltext

Quelle

American Physical Society

Beschreibungen/Notizen

• A basic tenet of material science is that the flow stress of a metal increases as its grain size decreases, an effect described by the Hall-Petch relation. This relation is used extensively in material design to optimize the hardness, durability, survivability, and ductility of structural metals. This Letter reports experimental results in a new regime of high pressures and strain rates that challenge this basic tenet of mechanical metallurgy. We report measurements of the plastic flow of the model body-centered-cubic metal tantalum made under conditions of high pressure (>100  GPa) and strain rate (∼10(7)  s(-1)) achieved by using the Omega laser. Under these unique plastic deformation ("flow") conditions, the effect of grain size is found to be negligible for grain sizes >0.25  μm sizes. A multiscale model of the plastic flow suggests that pressure and strain rate hardening dominate over the grain-size effects. Theoretical estimates, based on grain compatibility and geometrically necessary dislocations, corroborate this conclusion.