A precision additive manufacturing method based on laser powder bed fusion (LPBF) is applicable to the forming of various precise and complex structures

and has attracted increasing attention in the field of nuclear energy additive manufacturing. Inconel 625

as a nickel-based alloy with excellent high-temperature properties

holds significant application prospects in nuclear heat exchange equipment. In this study

LPBF forming process parameters were investigated for Inconel 625 nickel-based alloy. Thirty sets of process parameters were designed with laser power (250-500 W) and scanning speed (800-1

200 mm/s) as variables

and the optimal process window was screened through Archimedes density measurements and metallographic characterization. Subsequently

solution heat treatments at 1

090–1

180 °C (held for 1 h) were performed on the as-deposited specimens

and the microstructure

room-temperature tensile properties

impact properties

and physical properties (coefficient of thermal expansion and thermal conductivity) of the heat-treated specimens were systematically characterized. The results show that at a laser power of 350 W and a scanning speed of 1

100 mm/s

the relative density of the specimens reaches 99.96% with an average grain size of 76.5 μm

exhibiting a uniform and dense microstructure. After solution treatment at 1

120 ℃

the room-temperature ultimate tensile strength of specimens in the X

Y

and Z directions all exceed 885 MPa

the yield strength exceeds 543 MPa

and the elongation after fracture exceeds 39.3%. The impact absorbed energy differs significantly among the three directions. When the solution treatment temperature exceeds 1

120 ℃

the yield strength of the alloy decreases notably

while the anisotropy is markedly improved. In the temperature range of 250-350 ℃

the instantaneous coefficient of thermal expansion is approximately 14×10

-6

/K

and the thermal conductivity gradually increases with rising temperature; both values show minor differences from

those of wrought Inconel 625. The research findings can provide effective support for the manufacturing and performance evaluation of nuclear heat exchange equipment.