INTERACTION VOLUME EFFECTS OF ULTRASONICALLY CONSOLIDATED CU-AL CONCENTRATION PROFILES

摘要

Ultrasonic consolidation is an attractive manufacturing method to bond and fabricate multimaterialcomposite structures. Concentration profiles acquired through x-ray energy dispersivespectroscopy (XEDS) within the scanning electron microscope (SEM) are often used tocharacterize diffusion. Interaction volume interference, however, has a significant impact onaccurate measurement of concentration profiles for short-range diffusion. Concentration profilesgenerated through Monte Carlo simulations of electron trajectories showed broader diffusioncurves for higher accelerating voltages, resulting in higher calculated interdiffusion coefficients.XEDS of ultrasonically consolidated Cu-Al showed a diffusion distance of less than 2 microns,which is the same order of magnitude as the interaction volume interference. In this case, XEDSin the SEM can lead to significant errors in concentration profiles and is not a valid technique tomeasure interdiffusion coefficients for ultrasonically consolidated materials. For other diffusionprocesses, SEM XEDS can be a valid technique if a low accelerating voltage is used and thediffusion distance is large.