Effect of ZrH2 particles on the microstructure and mechanical properties of IN718 manufactured by selective laser melting

Coupled effect of microstructure and topology on the mechanical behavior of Inconel718 additively manufactured lattices

“…Table 4 summarizes the average yield stress, the ultimate tensile stress, and the tensile ductility corresponding to all the tests. The measured values lie within the relatively wide property ranges published for LPBF-processed Inconel718, which are often better than those reported for the as-cast condition [29,30,[35][36][37][38][39]. It can be seen that, for a given temperature, aging leads to a significant increase in the yield strength and in the ultimate tensile strength thanks to the precipitation hardening induced mainly by c 00 (Fig.…”

“…The hardness was measured in polished cross sections of the as-built and aged lattices perpendicular to the BD using a Shimadzu microhardness indenter, with forces of 4.9 and 9.8 N, respectively, and a dwelling time of 15 s. Ten hardness measurements were performed for each condition. The hardness of the as-built lattices (317 ± 8 HV) increased during aging up to a maximum of 502 ± 9 HV after 6 h. It must be noted that the measured hardness levels achieved following the direct aging treatment, and in the absence of any solutionizing step, are similar or higher than those reported for peak aged Inconel718 following the standard two-stage heat treatment [29,30], and somewhat lower than those achieved by direct double aging (535 HV) [31,32]. Treatments longer than about 8-10 h resulted in softening of the lattice material.…”

“…The aging treatment did not lead to any major changes in the misorientation of the grain boundary network. In both cases, as is typical of LPBF processed superalloys [29][30][31], a high fraction of low angle boundaries, with misorientations smaller than 5°, was present.…”

The Influence of Metastable Cellular Structure on Deformation Behavior in Laser Additively Manufactured 316L Stainless Steel

“…The near one-step process leads to enhanced mechanical properties, including high yield strength, intermediate tensile ductility, and better fatigue resistance. From the microstructural aspect, typical metastable cellular structures (MCSs) resulted from LAM process play a central role for high strength and intermediate-to-high ductility in many LAM materials, e.g., 316L stainless steel (SS) [1,2], Al-based alloys [4,5] and Ni-based superalloys [6,7]. During LAM process, the intrinsic solidification features-including fast cooling rate of 10 4 ~10 6 K/s and repeated thermal passes lead to redistribution of local chemical composition during solidification, and consequentially prevailing MCSs far from well-equilibrated state.…”