Modified strain rate regime in ultrafine grained copper with silver micro-alloying

Y. Champion (1) , J. Bourgon (2) , Xavier Sauvage (3)

1 SIMaP - Science et Ingénierie des Matériaux et Procédés
2 ICMPE - Institut de Chimie et des Matériaux Paris-Est
3 GPM - Groupe de physique des matériaux

Ultrafine grained (UFG) copper with an average grain size of 115 nm was micro-alloyed with silver (UFG CuAg) to analyze its effect on strain rate sensitivity. The materials were prepared by sintering Ag mi-croalloyed-Cu ultrafine powder, using the spark plasma sintering (SPS) technique and after H 2 pre-an-nealing for oxide reduction. Mechanical tests show that UFG CuAg follows the law of behavior established for UFG Cu: σ σ ≈ (−) m B 1 / 0 , relating the strain rate sensitivity m and the applied stress, σ. In this relation, σ 0 is a threshold grain size dependent stress and B is characterizing the grain boundaries diffusion properties. Main difference compared to pure UFG copper is a large value of the parameter B for UFG CuAg, indicating a dominant role of the grain boundaries structure and chemistry on the rheology of UFG metals.

Mots clés: Micro-alloying; Silver; Strain rate; Strength; Ultrafine grained; Copper

Domaines: Matériaux

Y. Champion, J. Bourgon, Xavier Sauvage. Modified strain rate regime in ultrafine grained copper with silver micro-alloying. Materials Science and Engineering: A, 2016, 657, pp.1 - 5. ⟨10.1016/j.msea.2016.01.044⟩. ⟨hal-01622946⟩