This study integrated the design concepts of high-entropy alloys and traditional superalloys to develop a precipitation-strengthened overlay high-entropy alloy, Al 6.9 Ti 6.9 Cr 15.5 Fe 34.5 Ni 36.2 . The study focused on revealing the nucleation, growth, and interaction mechanisms of L12 precipitated with dislocations at the nanoscale, combined with the synergistic effects of BCC/B2 phases. This article systematically analyzed the hightemperature mechanical properties, microstructure evolution, and dislocation motion laws of alloys from room temperature to 900 °C. The results indicated that the dispersed nanoscale L12 (Ni3 (Al, Ti)) phase (particle size ≤ 50 nm) in the post weld alloy matrix serves as the core strengthening phase, forming a semi coherent interface with the FCC matrix. Strengthening and toughening were achieved through mechanisms such as dislocation cutting and interface pinning. The microstructure of the alloy was basically stable from room temperature to 800 °C, and a small amount of η brittle phase precipitated at 700 °C. Significant coarsening of dendrites and BCC phase at 900 °C; The tensile strength of the alloy decreasesd with increasing temperature, with tensile strengths of 806.1 MPa and 127.4 MPa at room temperature and 900 °C, respectively. The strength at all temperatures was higher than that of the traditional Inconel 625 high-temperature alloy. The dislocation motion was mainly planar slip from room temperature to 700 °C, and L12 nanophase was strengthened by the synergistic effect of slip Manuscript Click here to access/download;Manuscript;Manuscript.docx plane softening and dislocation dipole array. Above 800 °C, dislocations underwent polygonization dominated by climb and cross slip, while L12 phase still delayed matrix softening through interface strengthening. The secondary nano precipitation of BCC/B2 phase further regulated dislocation pile up and stress concentration, achieving synergistic strength and plasticity at high temperatures
Xu et al. (2026) studied this question.