Microstructural evolution, nanoprecipitation behavior and mechanical properties of selective laser melted high-performance grade 300 maraging steel

Crystallographic Features of Microstructure in Maraging Steel Fabricated by Selective Laser Melting

“…The melt pools were approximately 50-100 µ m high ( Figure 3a) and approximately 50 µ m wide (Figure 3b). They contained elongated cellar structures with a mean spacing of approximately 500 nm (Figure 3c,d), as reported in the literature [10,11,[19][20][21]. The elongation direction of the cellar structure appears to be independent of the presence of the melt pool boundaries.…”

“…During the cooling process, the locally irradiated areas are rapidly quenched from the austenitic region to reach temperatures that are lower than the martensite start temperature, resulting in the formation of a martensite structure that contributes strengthening materials. The strength level of SLM-fabricated maraging steels is approximately 1 GPa [9][10][11]. The subsequent aging at elevated temperatures (~460 • C) enhances the precipitation of fine intermetallic phases within the martensite structure, which further strengthens the materials [9][10][11].…”

“…The strength level of SLM-fabricated maraging steels is approximately 1 GPa [9][10][11]. The subsequent aging at elevated temperatures (~460 • C) enhances the precipitation of fine intermetallic phases within the martensite structure, which further strengthens the materials [9][10][11]. However, most previous studies have investigated the effect of laser scanning conditions and aging treatments on the mechanical properties (strength and fatigue) of SLM-fabricated maraging steels [11][12][13][14].…”

“…The subsequent aging at elevated temperatures (~460 • C) enhances the precipitation of fine intermetallic phases within the martensite structure, which further strengthens the materials [9][10][11]. However, most previous studies have investigated the effect of laser scanning conditions and aging treatments on the mechanical properties (strength and fatigue) of SLM-fabricated maraging steels [11][12][13][14]. Although the crystallographic orientation relation has been determined in as-quenched maraging steels [15], the microscopic features of the SLM-generated martensite structure remain unclear.…”

Sensitivity of direct metal laser sintering Maraging steel fatigue strength to build orientation and allowance for machining

“…Regarding the allowance factor, it refers to the allowance accounted during the machining task at every sample gage. According to Ta et al, 27 the volumetric percentages are respectively 89.7% and 10.3%. For the sake of clarity, consistently with Croccolo et al, 3 a double notation has been used: The sample sets have been identified by both their sequential number and a letter (H for horizontal, V for 3) vertical, and S for slanted), followed by a number indicating the entity of allowance.…”