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This research explores how variations in laser powder bed fusion (LPBF) parameters—laser power (P), scanning speed (v), and base plate preheating temperature (ϑp)—affect the mechanical properties of the EOS Co-Cr SP2 dental alloy. A central composite design (CCD) was used to optimize the process parameters. Mechanical testing focused on crucial properties for dental applications, including yield strength (Rp0.2), elongation (ε), toughness (KVa), and flexural strength (Rms). Microstructural analysis was conducted using light and electron microscopy, while XRD identified microstructural phases. Statistical analysis (ANOVA, Scheffé post hoc test, α = 0.05) revealed significant effects of P, v, and ϑp on the mechanical properties. Response surface models (RSMs) were developed, and optimal parameters were determined to achieve maximum toughness and flexural strength. Maximum values were obtained with laser power above 205 W and base plate preheating at 310 °C. The mathematical model predicted toughness values with less than 5% deviation from experimental results, indicating high accuracy. [ABSTRACT FROM AUTHOR]

Nowadays, nuclear energy is one of the most replaceable energy sources for a broader range of advantages [1]. Harsh service conditions are the main concern for the development of structural materials in nuclear applications [2]. The oxide dispersion strengthened (ODS) steel is the most promising candidate for fulfilling the desired criteria as structural materials for nuclear applications [3]. The present study uniquely revealed the newly formed microstructure of ODS steel fabricated by pulse plasma sintering (PPS) to establish the ability to work in extremely severe service conditions. The attempt to fabricate ODS steel by PPS could be the most commendable method over other conventional sintering methodologies. In this research, we produced austenitic ODS steels with Y2O3 addition. The ODS steel powders were produced using different mechanical alloying parameters: duration of 5, 10 and 50 hours of milling at 250 rpm in Ar atmosphere. The influence of 1 wt.% of Y2O3 on the fabrication of ODS steel by PPS has been investigated in terms of microstructure, mechanical properties and corrosion resistivity. Microstructure has been evaluated by SEM, EDS, XRD, TEM and EBSD, mechanical tests were made using an uniaxial tensile test and microhardness, while corrosion resistance was evaluated based on electrochemical tests The microstructural study revealed that the properties of the produced materials depends on the mechanical alloying conditions. The highest tensile strength was achieved after mechanical alloying during 50 h, while the lowest after 5 h of mechanical alloying. The highest elongation was measured after 5 hours of powder milling. It may be supposed that a fine and uniform distribution of oxide particles helps to resist corrosion in ODS steel as compared to coarse grains formed after shorter milling times. [ABSTRACT FROM AUTHOR]

Modified aluminium alloy EN AW 7075 was LPBF processed (laser powder-bed fusion, also known as a selective laser melted (SLM) process) with different process parameters and various element additions. Due to the interesting behaviour of the samples, where different additions of elements play their role in the material, we performed a systematic and detailed microstructural characterisation. The samples for microstructure investigation were prepared according to a standard metallographic process by grinding and polishing in the samples' built-up direction. Characterisation was done by light (LM), scanning electron microscopy (SEM) and the selected samples were prepared and characterized by transmission electron microscopy (TEM). For SEM analyses, it was necessary to additionally prepare the surface of the samples with a short OPS polishing. From the results of the SEM EBSD and EDS analyses, we see the microstructure evolution, which led to improved mechanical properties of the final material. Small phases observed by SEM were systematically analysed by TEM, where we could conclude which precipitates influence the material during the AM process and improve the mechanical properties, which can be achieved only by AM techniques. [ABSTRACT FROM AUTHOR]

PBF-LB/M is a metal additive manufacturing process that enables the production of complex-shaped products with very low porosity and excellent mechanical properties. However, different laser beam shapes and varying energy inputs during the LPBF process affect the solidification rate and microstructure development. We investigated and compared the microstructures using samples made with the standard Gaussian laser beam and two laser beams in the shape of a Donut. It was found that changing the laser beam shape and volume energy input increases the grain size and texture. However, the cellular dendritic structure remains very similar, as does the fraction of the Laves phase. The samples were heat-treated at different temperatures, and we tracked the microstructure development, which revealed that carbides begin to form at specific temperatures. These carbides can be undesirable for mechanical properties due to their notch effect. At higher laser energy inputs, somewhat larger segregations may occur, which can influence carbide precipitation. [ABSTRACT FROM AUTHOR]