Fig. 1. Material‒structure‒performance integrated LAM technology in multifunctional design and manufacturing^[7]

Fig. 2. Morphology and cracking mechanism of solidification crack in LAM nickel-based superalloys. (a) Correlation between solid phase fraction and solidification cracking index (SCI)^[24]; (b) schematic diagram of cracking mechanism^[25]; (c) solidification crack in CM247LC alloy^[24]; (d) solidification crack in IN939 alloy^[24]

Fig. 3. Morphology and cracking mechanism of liquation crack in LAM nickel-based superalloys. (a) Constitutional liquation^[1,24];

Fig. 4. Differential scanning calorimetry curves and morphology of ABD-850AM, CM247LC and IN939 alloys^[24]

Fig. 5. DDC and its relationship with temperature in LAM nickel-based superalloys. (a) Morphology of DDC in IN738 alloy^[34];

Fig. 6. Calculation and design of formable new γ' phase strengthened nickel-based superalloys. (a) Relationship between SAC risk and Al, Ti+Nb+Ta contents^[24]; (b) γ' phase morphology and size in different generations of nickel-based single crystal superalloys^[40]; (c) relationship between mole fraction of γ' phase and SAC merit index^[24]; (d) relationship between creep life and SAC merit index^[24]

Fig. 7. Relationship between the integrity of LAM component and process parameters and alloy composition^[9,37]. (a) Defects caused by incompatibility between laser process parameters and alloy composition; (b) influence of composition optimization on solidification characteristics and formability of alloys

Fig. 8. Inhibitory effect of composition modification on crack in nickel-based superalloys. (a) Mechanism of reduced cracking sensitivity in new γ' phase strengthened MAD542 alloy^[41]; (b) influence of Zr content on crack density, size and quantity of carbide and ΔT of IN738LC alloy^[45]

Fig. 9. Inhibitory effect of adding nanoparticles on crack in nickel-based superalloys. (a) Influence of 2.5% TiC on grain morphology and solute enrichment in IN738LC alloy^[51]; (b) influence of 0.1% GNPs on grain morphology and dislocation distribution in K418 alloy^[52]

Fig. 10. Defect control and mechanical properties of LAM IN738LC alloy^[18]. (a) Formability of IN738LC alloy under different laser powers and scanning speeds; (b) LPBF process map of IN738LC alloy; (c) influence of post-processing on tensile properties of as-printed samples at room temperature; (d) jet turbine blade fabricated by LPBF

Fig. 11. Thermodynamics-guided LAM superalloy design process^[72]. (a) Interdendritic composition segregation measured by APT; (b) influence of partitioning behavior of alloy element on T_solidus; (c) influence of alloy element on driving forces of phase formation, and a schematic diagram of the whole design process

Fig. 12. Prediction of crack susceptibility in LAM nickel-based superalloy^[76]. (a) Construction process of ML model; (b) fitting performance of ML models on training sets; (c) comprehensive influence of elements on crack susceptibility evaluated by ML prediction model

Fig. 13. Relationship between composition and formability of nickel-based superalloys. (a) Formability of nickel-based superalloys represented by the contents of Al+Ti and Cr+Co^[38]; (b) composition distribution of formable/unformable superalloys in Cr¯‒Al¯ system

Fig. 14. Cracking resistance and mechanical properties of MNiHEA alloy^[93]. (a) Relationship between average SCI value and solidification cracking in the last solidification stage; (b) uniaxial tensile engineering stress-strain curves; (c) strengthening and toughening mechanisms of as-built and aged alloys

Fig. 15. Research on cracking behavior of LAM γ' phase strengthened nickel-based superalloys. (a) Summary of cracks causes and control methods^[66]; (b) comparison of room-temperature tensile properties of representative formable and unformable superalloys before and after crack control^[1]

Table 1. Effects of elements on the metallurgical performance of γ' phase strengthened nickel-based superalloys^[16]

Table 2. Composition and cluster formula analysis of nickel-based superalloys^{[44,82,84-86]}