The Use of Analytical Electron Microcopy to Evaluate Fusion Boundary Microstructure Evolution in Zr- and Sc-Bearing Aluminum Alloys

摘要

1. As welded or low temperature aged (300℃) substrates of both Zr and Sc bearing alloys do not promote EQZ formation. 2. Sc-containing substrate in the solution heat-treated condition produces an EQZ. 3. Irrespective of substrate condition, lowering Zr and potentially Sc contents eliminates EQZ formation. 4. OIM analysis confirms epitaxy as the dominant solidification mode when EQZ is absent while the random orientations of the non-dendritic equi-axed grains confirm that this zone in Zr- (or Sc) bearing alloys, is formed via a heterogeneous nucleation mechanism. 5. Micro diffraction analysis confirms that non-dendritic grains within the EQZ of the alloy 2195 are the result of solidification phenomena.