| Abstract Scope |
Unit cell topology and mechanical properties at room-temperature and 650℃ of additively manufactured IN718 lattice structures were investigated. 12-different lattice structures (BCC, FCC, BCCZ, FCCZ with 2mm, 3mm, 4mm unit-cell sizes; Z means strut designed along the build-direction) were manufactured by laser powder bed fusion process. Solution treatment and standard-aging were also conducted. The relative density of lattice structures were measured 11%~34% according to topology of unit-cell. In standard-aged strut, γ΄, γ΄΄, δ and carbide were observed and analyzed. The characteristic of compressive stress-strain curves followed the general trend of typical lattice structures. However, despite BCCZ has highest relative density, FCCZ shows higher compressive strength in all unit-cell size than BCCZ at RT (FCCZ:180.1MPa, BCCZ:155.7MPa in 2mm unit-cell) and 650℃ (FCCZ:158.5MPa, BCCZ:102.3MPa in 2mm unit-cell). In addition, standard-aged specimens show 20% higher compressive strength on average than as-built. Correlations between structural and microstructural characteristics and deformation behavior were also discussed. |