Powder bed binder jet printed alloy 625: Densification, microstructure and mechanical properties

Highlights: • Powder bed binder jet printing of alloy 625 argon atomized powder • Sintering from 1200 to 1300 °C with 99.6% maximum density at 1280 °C for 4 h • Chemical composition and phase formation analyses confirmed formation of various precipitates. • Alloy 625 produced by BJP had similar mechanical properties as cast alloy 625. Powder bed binder jet printing is an additive manufacturing method in which powder is deposited layer-by-layer and selectively joined in each layer with binder. Since the powder does not melt during printing, the density after printing is about 50%, and sintering is needed to densify as-printed parts. In this study, we investigate the effect of sintering temperature on density, microstructure, phase formation and mechanical properties of power bed binder jet printed alloy 625 parts. To determine the sintering temperatures, the as-received powder was subjected to differential scanning calorimetry analysis, and printed samples were cured and sintered at various temperatures under high vacuum. Density measurements, elemental analysis, phase formation and microstructure of as-printed, cured and sintered samples were investigated compared with mechanical properties. Results indicate that a fully densified parts with densities of up to 99.6%, as well as favorable mechanical properties (hardness of up to 238 HV_0.1 and UTS of up to 612 MPa) may be obtained for the sample sintered at 1280 °C. It is concluded that alloy 625 produced by powder bed binder jet printing can achieve similar density and mechanical properties as cast alloy 625.