Aluminum alloys are widely used in lightweight applications but frequently suffer mechanical degradation athigh temperatures due to phase coarsening. This study presents a novel Al-6.5Ni-1.4Fe-0.9Zr (wt.%) neareutecticalloy, designed using thermodynamic principles and non-equilibrium solidification modeling to optimizeboth printability and mechanical performance. Fabricated via laser powder bed fusion, the alloy exhibitsfine grains in both the horizontal and vertical planes, refined by Zr-induced nucleation, thereby minimizingmicrostructural anisotropy. The as-built alloy achieves a yield strength of 395 MPa and ultimate tensile strengthof 560 MPa, primarily attributed to its refined ~300 nm cellular microstructure and high dislocation density.After 100 h of thermal exposure at 350 ◦C, the alloy maintains stable hardness and demonstrates superior heatresistance. In situ synchrotron X-ray diffraction was used to analyze dislocation density evolution using theWilliamson-Hall method, revealing increased dislocation accumulation during tensile loading and partial recoveryafter aging. Nanosized L12-Al3Zr precipitates with coherent interfaces contribute to thermal stability,exhibiting a low coarsening rate of 6.1 nm3/s at 400 ◦C. These findings underscore the potential of the Al-6.5Ni-1.4Fe-0.9Zr alloy for high-performance applications in environments where long-term thermal stability andmechanical integrity are crucial.
Li et al. (2026) studied this question.