|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Multiscale Architectured Materials (MAM II): Tailoring Mechanical Incompatibility for Superior Properties
||High Temperature Plasticity of Cu-Cr Nanolayered and Chemically Nanostructured Cu-Cr Films
||Gerhard Dehm, T. Harzer, C. Liebscher, R. Raghavan
|On-Site Speaker (Planned)
This talk reviews the influence of microstructure evolution on the plasticity of Cu-Cr films using two microstructure concepts: nanolayering versus nanostructuring. PVD was used to create Cu-Cr nanolayered and alloyed films of identical composition. Alloyed films with 66at%Cu (Cu66Cr34) and Cu20Cr80 were found to form supersaturated solid solutions which consist only of bcc nanocrystals rather than fcc and bcc grains as thermodynamically expected. Advanced TEM studies reveal a hierarchical nanostructure for the bcc Cu66Cr34 alloy film: the supersaturated grains start to phase separate by spinodal decomposition leading to chemical gradients on the length-scale of a few nanometers. While the nanolayered Cu-Cr films reveal higher strength in microcompression testing at 25°C than the alloyed Cu-Cr films, they are more prone to diffusion assisted deformation at elevated temperatures. In contrast, the nanocrystalline grain size and chemical modulations within the supersaturated bcc grains lead to an improved mechanical performance at elevated temperature.