Effect of lattice preferred orientation on lattice strains in polycrystalline materials deformed under high pressure: Application to hcp-Co

The present paper readdresses the issue of stress and strain analysis for hcp-metals plastically deformed under high pressure in the diamond anvil cell with an application to cobalt at 42 GPa. The effective single crystal elastic moduli deduced from radial X-ray diffraction under Reuss or geometric averages, including effects of lattice preferred orientations, and assuming a constant stress within the sample, consistently differ from those measured with other technique with the largest deviations observed on C44. These results are then interpreted as an (hkl)-dependent effective differential stress.