Influences of microstructure and orientation on fracture toughness of intermetallic phase Al₂Cu‐based alloy under directional solidification

Abstract

The influences of microstructures and orientations on fracture toughness of intermetallic phase Al2Cu‐based alloys during different directionally solidified rates were investigated. With solidified rates increasing, the patterns of Al2Cu phase dendrite turned from faceted V‐shaped morphology to elongated plate‐shaped morphology and discontinuous complex morphology in longitudinal section. Moreover, the deviation angle between the growth direction of Al2Cu dendrite and the heat flow direction was increasing. Because of fine grain toughening and crack propagation path deflected by orientation, the fracture toughness of Al2Cu‐based alloy was improved. The experimental results showed that improving the brittleness could be well achieved under higher directionally solidified rate.

Combinatorial investigation of Al–Cu intermetallics using small-scale mechanical testing

“…p-17-at the top of the pillar, while the fracture surface of Delta phase (Figure 5b) exhibits a quasicleavage feature with slightly river markings. Cleavage fracture in the Theta phase has been previously reported using bulk three point bending tests at room temperature [51] and results from crack propagation initiating and extending along the (001) cleavage plane. Since the variation between conventional nanoindentation results was quite small for several phases (Figure 2), and micropillar testing is limited to a relatively small number of grains with different crystallographic orientations; statistical sampling of the intermetallic phases with hundreds of interrogated grains was performed using the NanoBlitz indentation mapping technique.…”

Archives of Metallurgy and Materials

“…3, and there had a certain deviation angle between these two directions. Thus the deviation angle of twinned dendrite was investigated and characterized by the EBSD analysis [15]. Figure 4 shows the EBSD maps in the transverse section, the corresponding (110)-pole figures and inverse pole figure of Al twinned dendrite at 1000 μm/s, respectively.…”