Investigation on β' phase inversion of peak-aging hot extruded GW84 alloy after short high temperature secondary aging

The beta' phase rapid transformation of peak-aging hot extruded GW84 alloy after short secondary aging at 250 degrees C and 300 degrees C were studied in this paper. The results show that strengthening phase, beta' phase (Mg-7(Gd,Y,Sm)) changed obviously, which is not recognised in previous studies. The strengthening phase is metastable beta' at first aging 200 degrees C x 96 h. After secondary aging at 250 degrees C for 7 min, some beta' precipitates transform into nano beta (Mg-5(Gd,Y,Sm)) particles, which exist at grain boundary, but there are still some beta' precipitates remaining at grain boundary. After secondary aging for 300 degrees C x 7 min, beta' precipitates completely transform into beta particles, which grow up to sub-micron particles at grain boundary. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The rapid transformation of the strengthening phase beta' phase in GW84 alloy after short secondary aging at 250°C and 300°C was studied, revealing the transition of some beta' precipitates into nano beta particles and eventually completely transforming into beta particles.