The role of TEM specimen preparation in understanding aluminum alloy precipitation hardening mechanism
Precipitation hardening is the most commonly used method to enhance the mechanical properties of aluminum alloys. By utilizing the NanoMill system, researchers can precisely target specific regions on conventionally prepared specimens, producing high-quality TEM samples with optimal thickness for high-resolution TEM and aberration-corrected STEM imaging and analysis.
TEM specimen preparation of aluminum alloys AA7050 and AA2050 by electropolishing and concentrated Ar ion milling is demonstrated.
The ability to target a region of interest on conventionally prepared specimens using the NanoMill system results in TEM specimens of high quality and thickness suitable for HRTEM and aberration-corrected HAADF-STEM imaging
and analysis. Through atomic-resolution TEM and STEM, the evolution of precipitates from GP zones, GPII for AA7050 and GP(T1) and GP(θ”) for AA2050, meta-stable precipitates, η’ for AA7050 and T1 and θ’ for AA2050; to stable precipitates, η for AA7050, is identified. The transformation of the GP zones to the meta-stable precipitates is driven by in situ nucleation during the transformation step for both alloy systems.
