Strain-Induced Surface Dynamics of Aluminum Studied by In Situ Photoelectron Emission

Abstract

In situ photoelectron emission in high-purity aluminum deformed under uniaxial tension while exposed to pulsed excimer laser radiation (248 nm) is reported in this paper. The effect of various surface treatments, including polishing, air oxidization, carbon coating, and gold coating, on photoelectron emission was investigated. The photoelectron emission signals are sensitive to strain-induced surface structure changes, such as slip lines and slip bands. In the case of aluminum with oxide of 4.5 nm thickness, the photoelectron emission increases gradually in a nonlinear fashion at the early stage of deformation (strain ≤0.05). Then the photoemission grows linearly until the accumulated strain reaches about 0.17. In the final stage, the photoelectron intensity increases parabolically until failure. The transition of photoelectron emission from linear to parabolic growth correlates with the onset of strain localization. The strain-induced microstructural change was also analyzed by scanning electron microscopy (SEM). The photoelectron emission signals from aluminum during tension were interpreted in the light of surface treatment, surface electron work function, and surface microstructural change.