Synergetic effects of trace Sc/Zr/TiB2 on recrystallization and strengthening behavior of Al–Mg alloys

The development of a new generation of high-performance Al alloys, achieved through Sc/Zr-modified Al–Mg-based alloys, is attracting growing attention. However, the significant cost associated with Sc presents a barrier to further advancement. In this study, the inclusion of trace heterogeneous TiB₂ particles is employed to regulate the microstructural evolution process, thereby achieving high-performance aluminum alloys with optimal strength-ductility characteristics with minimal Sc addition. The ultimate tensile strength of Al–Mg-Sc-Zr-TiB₂ alloy reached 442.4 MPa, with a elongation of 16.6%. The combined impact of TiB₂ particles and Al₃(Sc,Zr) precipitates on the microstructure evolution of the Al–Mg alloy during hot deformation was investigated. It was observed that spherical Al₃(Sc,Zr) precipitates with sizes ranging from 5 to 10 nm dispersed in the matrix, during the hot deformation process, functioned as Zener pinning sites for dislocations, thus increasing the proportion of low-angle grain boundaries (LAGBs) and suppressing the dynamic recrystallization (DRX) process. The incorporation of trace TiB₂ particles induced the particle-stimulated nucleation effect, accelerating DRX and refining the microstructure. The density of LAGBs further increased, and the proportion of continuous dynamic recrystallization also rose. Furthermore, the TiB₂ particles mitigated the anisotropy of material and inhibited DRX grain growth, thereby expanding the subsequent processing window and offering more potential applications for the materials. This study provides new insights into the production of high-performance Al alloy products.

Graphical abstract