Quasistatic and dynamic mechanical response of laser powder bed fusion manufactured AA2219 alloy at cryogenic temperature

This work presents the mechanical assessment of AA2219 alloy, fabricated via Laser Powder Bed Fusion (LPBF), at - 196 °C in as-built (AB), T5 and T6 heat treated conditions. Cryo-hardness increased from 89 ± 1 BHN in the AB condition to 104 ± 3 BHN and 128 ± 2 BHN for the T5 and T6 conditions, respectively. Cryo-tensile testing was used to measure the yield strength (YS), ultimate tensile strength (UTS), and elongation at fracture. Results for the AB, T5 and T6 samples were 175 MPa, 352 MPa, 10.9%, 192 MPa, 376 MPa, 13.6% and 310 MPa, 487 MPa and 13.2%, respectively. The Cryo-Charpy energy of initiation (E_i) of the AB, T5 and T6 samples was 5.1 J, 4.4 J and 5.9 J, respectively, while the energy of propagation (Ep) showed a decreasing trend across the same samples, measuring 6.3 J, 4.7 J, and 2.7 J, respectively. This research elucidates the underlying mechanisms responsible for the varying combinations of strength and ductility observed at - 196 °C.