Shear Localization in Nanocrystalline Metals: A Combined Atomistic and Experimental Study
Amirhossein Khalajhedayati (UC Irvine), Timothy Rupert (UC Irvine)
From Atomistics to Reality: Spanning Scales in Simulations and Experiments Symposium A
Wed 10:45 - 12:15
CIT 165
Nanocrystalline metals exhibit great strength and unique deformation physics due to the dramatic increase in grain boundary volume fraction that accompanies nanostructuring. Evidence has emerged that the finest nanocrystalline metals deform in a manner that resembles metallic glass behavior, with increased pressure sensitivity of strength and a propensity for shear localization being reported in the literature. The possibility of shear banding is especially important and requires further study, as such behavior would limit practical usage and counteract any gains in strength that are achieved. In this talk, we first report on nanoindentation and microcompression experiments where shear banding is observed and discuss the implications of such behavior for real-world materials failure. Next, we use atomistic modeling to explore the physics of shear localization in nanocrystalline metals, with an emphasis on understanding atomistic mechanisms and the testing conditions which promote localization. Finally, by combining our modeling and experimental results, we propose paths for restricting localized failure in nanocrystalline materials.