The effect of Al and Ti additions on the microstructure and properties of CoNiFe alloys was studied in this paper. The investigations were conducted on four specially designed and produced arc furnace alloys (from 3 to 5 components, with medium to high entropy). Samples in various states were analyzed, i.e., as-cast, after homogenization, after solution heat treatment, and after solution heat treatment and aging. The obtained samples were characterized by: SEM observations, EDS, XRD, TEM analyses, and finally, hardness measurements. The solid solution strengthening coming from the addition of 5 at. pct. Al was negligible, while the effect from the 5 at. pct. of Ti addition was significant. The precipitation hardening effect related to the presence of the (CoNi)₃Ti phase caused by the Ti addition is comparable with the total effect of the Al and Ti addition, which caused the precipitation of (NiCo)₃AlTi.

In this work, the influence of chromium and titanium on the microstructure and mechanical properties of cast steel is investigated. The analysis was carried out on a material covered by patent Pat.243157. Advanced techniques were used, including dilatometric analysis, light microscopy (LM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The material was examined in various states: as-cast, quenched, and quenched with subsequent tempering at 200?C, 400?C, and 600?C. Important mechanical properties such as hardness, yield strength, percentage elongation, percentage reduction in area after fracture, and impact toughness at temperatures ranging from -40?C to +20?C were evaluated. The results were compared with those of a reference cast steel without these alloying elements, allowing a detailed assessment of the influence of chromium and titanium. The investigation begins with a comprehensive literature review of the effects of these elements in iron-based alloys. The results highlight the influence of chromium and titanium on the mechanical properties and microstructural development of cast steel. These elements play a critical role in enhancing mechanical strength, particularly after quenching and tempering, although there are evident trade-offs in ductility and impact toughness. In addition, the study discusses the damage mechanisms, focusing on the role of titanium nitrides in the cracking process.

Additive manufacturing techniques employing laser-based metal melting have garnered significant attention within the scientific community. Despite a decade of comprehensive research on the fundamentals of these techniques, there still remain unexplored facets related to heat flux impact on metallic alloys’ properties. Particularly, the effects of point-by-point laser operation on melt pool formation in metallic materials still remain unclear. Thus, this study focuses on the implications of laser metal melting, particularly investigating a point-by-point laser mode operation’s influence on melt pool formation and its geometry in the phase-transformation-sensitive material H11 hot work tool steel. To examine the melt pool, singular laser tracks with various laser parameters were scanned across H11 sheet metal, which allowed for the elimination of layer-by-layer heat cycles’ influence on the melt pool’s microstructure. Samples were examined by means of metallography, revealing significant differences in the melt pool’s depth, influenced mostly by exposure time rather than volumetric energy density. Heat-affected zone effects were found to have a limited range and thus potentially marginal effects in layer-by-layer manufacturing conditions. At the same time, retained austenite concentrations near fusion lines have been found within melt pools, suggesting potential micro-segregation of the alloying additions. The results present guidelines towards laser melting processes optimization.