Powder Bed Fusion of metals using laser beam (PBF-LB/M) relies on stable single-track and single-layer deposition to produce dense, and defect-free components, a requirement that is particularly challenging in bimetallic systems with dissimilar thermophysical properties. This study investigated the effects of PBF-LB/M process parameters on single-track and single-layer deposition in a bimetallic system comprising M300 maraging steel and C18150 copper alloy. An SLM 280 2.0 2MA PBF-LB/M machine equipped with twin 700 W IPG Ytterbium fiber lasers was used to print the bimetal samples. Laser scan velocities (500–1100 mm/s), laser powers (300–550 W), and hatch spacings (0.08–0.14 mm) were systematically varied for deposition of M300 on C18150 substrates and vice versa. Surface integrity was quantified using surface roughness parameters (Ra and Sa), while melt pool geometry and interfacial characteristics were analysed using optical and scanning electron microscopy. For single tracks of M300 deposited on C18150, increasing scan velocity led to higher surface roughness and reduced melt pool width and depth, whereas higher laser power increased melt pool dimensions. In contrast, single tracks of C18150 deposited on M300 exhibited discontinuous tracks, high variability in melt pool geometry, and unstable deposition behaviour. Single-layer results revealed smoother surfaces for M300 on C18150 under low scan velocity, 500–700 mm/s, small hatch spacing, 0.08–0.1 mm and high laser power, 400–450 W. The reverse configuration, C18150 on M300, however, rendered better surface quality at the same velocity and hatch space ranges but at higher power, 500–550 W. The lowest surface roughness (Ra = 15.7 ± 1.9 μm; Sa = 19.9 ± 0.4 μm ) was for M300 on C18150 configuration and for C18150 on M300 (Ra = 14.9 ± 7.1 μm; Sa = 48 ± 16 μm). Interfacial analysis showed material intermixing in both configurations, with more pronounced defect formation when depositing C18150 on M300. Overall, the results of this study provide critical insights into the process–structure relationships governing bimetallic PBF-LB/M fabrication and contribute to the advancement of parameter optimisation strategies for the production of structurally sound bimetallic components.
Laser powder bed fusion (LPBF) of CuCrZr is attractive for actively cooled, high-heat-flux components; however, the conventional post-heat treatment, solution annealing and ageing, is difficult to transfer to large and geometrically complex additively manufactured parts because quenching may promote distortions and cracking. A quench-free direct ageing would be industrially attractive if it preserves fatigue performance. In the present work, two industrially established LPBF CuCrZr conditions were compared: a directly aged material produced with an 80 μm layer thickness (DAH-80) and a solution-annealed and aged material with a 60 μm layer thickness (SA + AH-60). The routes differ not only in post-processing, but also in layer thickness and LPBF system; they are therefore assessed as production packages rather than isolated heat-treatment variants. Density, hardness, tensile properties, smooth and notched high-cycle fatigue (HCF), notch sensitivity (Theory of Critical Distances and the Averaged Strain Energy Density approaches), defect tolerance (El Haddad–corrected Kitagawa–Takahashi diagram) and low-cycle fatigue (LCF) were investigated. Despite a large gap in ultimate tensile strength (UTS, 478 vs. 359 MPa), the two routes show the same smooth HCF strength within 4
Additive manufacturing (AM) has revolutionized manufacturing processes by enabling the production of geometrically complex components coupled with the advantage of faster production times. Among its most promising advancements is the fabrication of polymer matrix composites which combine the benefits of lightweight design with high mechanical performance, through an additive manufacturing process referred to as Continuous Fiber Fabrication (CFF). This study is novel in that it assesses the torsional performance of Onyx® composites (i.e., nylon matrix comprised of chopped carbon fiber) and its fiber-reinforced variants (i.e., incorporation of continuous fibers such as Kevlar®(KF), or fiberglass (FG)), manufactured along the X-build orientation, with 0° fiber orientation. Experimental results revealed that unreinforced Onyx® composite specimens exhibited overall enhanced torsional performance as compared with its continuous fiber reinforced variants, achieving an average shear modulus, G, of 526.91 ± 94.57 MPa and average shear strain at failure, γ, of 1.73 ± 0.13 rad. Among the fiber-reinforced variants, Onyx®-fiberglass composite specimens exhibited the highest average shear strength, τ, of 64.06 ± 1.98 MPa, representing a 8.3
FDM technology is widely used for manufacturing polymers and composites, and acetone-based treatments are commonly employed for post-processing and surface finishing. However, the effect of direct liquid-acetone exposure on the structural integrity of FDM-fabricated materials particularly biocomposites remains insufficiently understood, presenting a practical concern where accidental solvent contact could compromise the structural performance of printed components. In the present work, the degradation behavior of FDM-printed PLA (polylactic acid), PLA–carbon fiber (CF), PLA–walnut wood fiber (WWF), and TPU (thermoplastic polyurethane) was experimentally evaluated under total liquid-acetone immersion at 25 ± 2 °C for up to 30 min, with observations recorded at 5 min intervals using optical microscopy, SEM, and FTIR. Degradation was quantified through surface erosion, crack density, dimensional stability, and time to structural failure, and these indicators were subsequently integrated into a hybrid CRITIC–Entropy–TOPSIS multi-criteria decision-making framework to compare the four material systems. PLA-WWF exhibited the most severe deterioration, with approximately 95
Triply periodic minimal surface (TPMS) lattices offer strong potential for lightweight structural and energy-absorbing applications, however, the coupled influence of lattice topology, relative density, and post-processing-induced microstructural changes on their mechanical response remains insufficiently understood. In this study, Gyroid, Diamond, Primitive, and IWP AlSi10Mg TPMS lattices were fabricated via laser powder bed fusion (PBF-LB/M) at three relative densities and investigated in both as-built and EOS T6 heat-treated conditions. Quasi-static compression testing up to 50
