Mechanical behavior of high-density nanocrystalline gold prepared by gas deposition method

• Published in: Acta materialia 1998-12, Vol.47 (1), p.211-217
• Main Authors: Sakai, S., Tanimoto, H., Mizubayashi, H.
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: structure, mechanical and thermal properties; Elasticity, elastic constants; Exact sciences and technology; Mechanical and acoustical properties of condensed matter; Mechanical properties of solids; Metals. Metallurgy; Physics
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/S1359-6454(98)00339-5

Nanocrystalline gold (n-Au) specimens with the theoretical density were prepared using the gas deposition method, and mechanical tests were carried out. In the elastic range, the Young's modulus found below 80 K for n-Au specimens with mean grain size of 26–60 nm is higher than 92% of the bulk value, suggesting that the Young's modulus in the grain boundary region is higher than 70% of the bulk value. Above 200 K, anelastic strain due to a certain relaxation in the grain boundary region increases with increasing temperature, giving a decrease in the Young's modulus. Plasticity tests were made near room temperature for n-Au specimens with mean grain size of 15–60 nm. The Hall–Petch relationship is observed in the Vickers microhardness tests with a holding time of 10 s, and creep deformation proceeds in quasi-static tensile tests for 10 3–10 5 s, indicating that the preferable plastic deformation process near room temperature in n-Au is governed by not only the stress level but also the strain rate.