Microstructure and Mechanical Properties of Additively Manufactured Haynes 282: A Comparative Analysis between Laser Powder Bed Fusion and Laser Powder Directed Energy Deposition Technologies

This study compares the microstructure and tensile properties of Haynes 282 fabricated using laser powder bed fusion and laser powder directed energy deposition. Both sets underwent stress-relieving, followed by hot isostatic pressing, and the standard double aging heat treatment. Tensile testing was conducted at room temperature on specimens fabricated with both technologies to evaluate and compare their tensile behaviors. Results show that the ultimate tensile and yield strengths of laser powder bed fused specimens were 18% and 57% higher, respectively than those of laser powder directed energy deposited ones, whereas the elongation to failure was similar in both. The difference in strengths is attributed to the differences in the size of γ' precipitates and grains, i.e., those in the laser powder directed energy deposited specimens being larger, whereas similar elongation to failure is attributed to the carbide debonding dominating the fracture mechanism in both batches.Mechanical Engineerin

Effect of heat treatment on the microstructure and mechanical properties of Monel K500 alloy fabricated via L-PBF and LP-DED

This study examines and compares the effect of different heat treatments (HT) on the microstructure and mechanical properties of Monel K500 fabricated using laser powder bed fusion (L-PBF) and laser powder directed energy deposition (LP-DED) technologies. The as-fabricated Monel K500 specimens exhibited dendritic microstructure and elemental micro-segregation due to high cooling rates induced during the fabrication process. The applicability of HT proposed in the literature for wrought Monel K500 was investigated for L-PBF and LP-DED using four different HT procedures involving hot isostatic pressing (HIP), solution annealing (SA), and aging. The mechanical properties of test specimens were evaluated using uniaxial tensile testing at room temperature. The microstructural evolution of test specimens during HT was analyzed using a scanning electron microscope. For all HT conditions investigated, L-PBF Monel K500 specimens consistently displayed higher strength and lower ductility compared to the LP-DED counterparts. The HT procedure involving HIP at 1160°C for 3hr at 100 MPa, SA at 1100°C for 15 min, and three step aging at 610°C for 16 hr, 540°C for 6 hr, and 480°C for 8 hr resulted in highest strength for both L-PBF and LP-DED fabricated Monel K500.Mechanical Engineerin

A Comparison of Microstructure and Mechanical Performance of Inconel 718 Manufactured via L-PBF, LP-DED, and WAAM Technologies

The microstructure and mechanical properties of additively manufactured (AM) alloys can be significantly affected by variations in cooling rates, resulting from different process conditions across different additive manufacturing (AM) platforms. Therefore, it is crucial to understand the effect of manufacturing process on the microstructure and mechanical properties of AM Inconel 718. This study examines three AM processes: laser powder bed fusion, laser powder directed energy deposition, and wire arc additive manufacturing. Results show that fully heat treated laser powder bed fused (L-PBF) and wire arc additively manufactured (WAAM) Inconel 718 specimens exhibit higher strength compared to laser powder directed energy deposited (LP-DED) ones due to finer grain structure in L-PBF and retained dendritic microstructure in WAAM. The ductility in LP-DED Inconel 718 was slightly higher compared to WAAM and L-PBF due to relatively small carbide size, which causes stress concentration in a small material volume, leading to delayed fracture.Mechanical Engineerin

Z-inertial fusion energy: power plant final report FY 2006.

This report summarizes the work conducted for the Z-inertial fusion energy (Z-IFE) late start Laboratory Directed Research Project. A major area of focus was on creating a roadmap to a z-pinch driven fusion power plant. The roadmap ties ZIFE into the Global Nuclear Energy Partnership (GNEP) initiative through the use of high energy fusion neutrons to burn the actinides of spent fuel waste. Transmutation presents a near term use for Z-IFE technology and will aid in paving the path to fusion energy. The work this year continued to develop the science and engineering needed to support the Z-IFE roadmap. This included plant system and driver cost estimates, recyclable transmission line studies, flibe characterization, reaction chamber design, and shock mitigation techniques

Additively Manufactured 316L Stainless Steel: Effect of Heat Treatment on Microstructure and Tensile Properties

The microstructure and tensile properties of 316L stainless steel (SS) fabricated using the laser powder directed energy deposition (LP-DED) after various heat treatment (HT) steps such as stress-relief (SR), solution annealing (SA), and hot isostatic pressing (HIP) are characterized. Microstructures before and after HTs are analyzed using both optical and scanning electron microscopy (SEM). Both quasi-static uniaxial tensile and hardness tests are performed to measure mechanical properties. The tensile results indicate that the non-heat treated (NHT) condition possesses higher strengths but lower ductility as compared to the other HT conditions (i.e., SR, SA, HIP, SR+SA, and SR+HIP). By employing the two-step HT conditions (i.e., SR+SA and SR+HIP), no significant changes on tensile properties as compared to the individual single-step HT conditions (i.e., SA or HIP) are observed. The findings suggest that two-step HTs are not required for LP-DED 316L SS unless HIP is needed to minimize volumetric defect contents.Mechanical Engineerin

Additively Manufactured Haynes 230 by Laser Powder Directed Energy Deposition (LP-DED): Effect of Heat Treatment on Microstructure and Tensile Properties

The microstructure and tensile mechanical properties of Haynes 230 fabricated through laser powder directed energy deposition (LP-DED) were investigated, varying temperature heat treatments between 900°C to 1177°C following deposition. Scanning electron microscopy (SEM) was employed for microstructural analysis, whilst tensile testing was utilized to evaluate the room temperature mechanical properties of the alloy. In an as-deposited state, the initial microstructure consisted of cellular γ and M6C/M23C6 carbides. The cellular regions seem to be fully dissolved upon solutionizing at 1177°C for 3 hours. Following post-deposition heat-treatments, the carbides were observed to precipitate and grow along the grain boundaries as well as in the interior of grains. Solutionizing at 1177°C for 3 hours following stress-relieving yielded better ductility and had an insignificant effect on the strength.Mechanical Engineerin

Microstructure and Mechanical Properties of Additively Manufactured Haynes 230: A Comparative Study of L-PBF vs. LP-DED

This study investigates the microstructure and room temperature mechanical properties of Haynes 230 fabricated via laser powder bed fusion (L-PBF) and laser powder directed energy deposition (LP-DED). Both L-PBF and LP-DED specimens underwent similar multiple-step heat treatments (HT): stress-relieving (1066°C for 1.5 hours), followed by hot isostatic pressing (at 1163°C and 103 MPa for 3 hours), and solution annealing (1177°C for 3 hours). Microstructural analysis was conducted employing a scanning electron microscope. Uniaxial tensile tests at room temperature were conducted to evaluate the mechanical properties. The change in microstructures after HT and tensile results for both L-PBF and LP-DED specimens were comparable. Upon HTs, the micro-segregation and dendritic microstructure observed in non-heat treated conditions were almost fully dissolved, and carbide phases (M6C/M23C6) formed within grain interiors and grain boundaries in both L-PBF and LP-DED specimens. Finally, the failure mechanisms under tensile load have been studied and compared by fractography.Mechanical Engineerin