An atomistic study on tensile behaviors of nanocrystalline copper

In the present work, tensile behaviors of nanocrystalline copper influenced by size evenness of nanograins, crystallographic orientation, grain sizes, temperature, and strain rates are investigated by using molecular dynamics simulations. Results show that Young's modulus decreases with decreasing grain sizes when grain sizes are smaller than 9.8 nm, which agrees well with the inverse Hall-Petch relation. It is also demonstrated that both strength and modulus of nanocrystalline copper with random-sized grains are slightly higher than those with even-sized nanograins. With increasing temperatures, the modulus generally decreases, while the deteriorate slope of random-sized grains is slightly steeper than that of even-sized grains and the modulus of random-sized presents higher when temperature is below 900 K. This work sheds deep insights into tensile behaviors of nanocrystalline coppers at the nanoscale.