Fig. 1. SEM morphology and elemental mapping of (CoCrNi)94Al3Ti3 alloy powder. (a) Secondary electron image showing spherical powder particle morphology; (b-f) EDS elemental maps: (b) Cr distribution; (c) Co distribution; (d) Ni distribution; (e) Al distribution; and (f) Ti distribution.

Fig. 2. (a) Schematic of SLM scanning strategy with the rotation angle of 67°; (b) dimensions of bulk samples and machined specimens for mechanical tensile testing.

Fig. 3. EBSD analysis of (CoCrNi)94Al3Ti3 alloy in the XOY plane: (a) IPF map showing grain morphology; (b) grain boundary distribution; (c) KAM map; (d) grain size distribution; (e) pole figures showing texture characteristics; (f) schematic diagram of three sequential stages in microstructural evolution.

Fig. 4. EBSD analysis of (CoCrNi)94Al3Ti3 alloy in the XOZ plane: (a) IPF map showing columnar grain morphology; (b) grain boundary distribution; (c) KAM map; (d) grain size distribution; (e) pole figures showing texture characteristics; (f) schematic illustration of directional growth characteristics along the building direction.

Fig. 5. Mechanical response of (CoCrNi)94Al3Ti3 alloy at different strain rates: (a) engineering stress-strain curves; (b) true stress-strain curves.

Fig. 6. Mechanical response of additively manufactured (CoCrNi)94Al3Ti3 alloy at 298 K and 77 K: (a) engineering stress-strain curves; (b) true stress-strain curves.

Fig. 7. SEM images of the fracture surfaces of the (CoCrNi)94Al3Ti3 alloy at different strain rates: (a1-d1) low magnification, (a2-d2) intermediate magnification, and (a3-d3) high magnification views. Strain rates: (a1-a3) 10−3 s−1, (b1-b3) 10−2 s−1, (c1-c3) 10−1 s−1, and (d1-d3) 7.5 × 10−1 s−1.

Fig. 8. Microstructural characteristics of (CoCrNi)94Al3Ti3 alloy deformed at different strain rates: (a-c) 10−3 s−1, (d-f) 10−2 s−1, (g-i) 10−1 s−1, and (j-l) 7.5 × 10−1 s−1. (a, d, g, j) IPF maps showing grain orientation distribution; (b, e, h, k) KAM distribution statistics with corresponding KAM maps (inset); (c, f, i, l) {100}, {110}, and {111} pole figures showing texture evolution.

Fig. 9. Grain boundary maps of the (CoCrNi)94Al3Ti3 alloy deformed at different strain rates: (a) 10−3 s−1, (b) 10−2 s−1, (c) 10−1 s−1, and (d) 7.5 × 10−1 s−1.

Fig. 10. EBSD analysis of (CoCrNi)94Al3Ti3 alloy deformed at 298 K (a-c) and 77 K (d-f): (a, d) IPF maps, (b, e) KAM maps, (c, f) grain boundary maps. Statistical analysis: (g, h) grain size distributions, (i) KAM value distribution, (j, k) pole figures showing {100}, {110}, and {111} orientations, and (l) misorientation angle distribution.

Fig. 11. TEM observation of the as-SLMed (CoCrNi)94Al3Ti3 alloy: (a) TEM bright-field image showing dislocation cells and high-density staggered zones; (b) high-density dislocation walls and dislocation tangles; (c) TEM bright-field image and corresponding EDS elemental mapping of Al, Ti, Co, Cr and Ni; (d) TEM image showing L12 precipitated phase; (e) high-resolution TEM image of the precipitated phase; (f) SAED pattern showing {111} reflections.

Fig. 12. Schematic illustration of L12 phase formation in CoCrNi-based alloy: (a) CoCrNi matrix structure; (b) Al and Ti doping and diffusion; (c) formation of L12 precipitates within CoCrNi matrix.

Fig. 13. Schematic of strain rate effects on dislocation behavior: (a) strain concentration at 10−3 s−1, (b) uniform slip at 10−2 s−1, and (c) blocked dislocation motion at 10−1 s−1.

Fig. 14. Schematic of deformation mechanisms at 77 K: (a) early stage with dislocations and slip bands, (b) late stage showing twin boundaries.