Search Results (4)

This study thoroughly investigates the influence of anisotropy on the formability of 2024-T3 aluminum alloy sheets using advanced techniques such as digital image correlation (DIC) and Marciniak tests. A key finding is the relatively small variation in anisotropy values across different strain paths and orientations, contrasting with more significant variations reported in other studies. Tests were conducted on nine samples with various geometries to induce specific strain paths, including uniaxial, plane, and balanced biaxial strains, oriented in different directions relative to the rolling direction. The study also provides a detailed analysis of microstructural and mechanical characteristics, such as precipitate distribution and anisotropy behavior, which are crucial for understanding the relationship between microstructure and material formability. The results show that while anisotropy impacts deformation capacity, the differences in formability among the directions were minimal, with slightly greater formability observed in the diagonal direction. These findings are compared with forming limit curves (FLCs), offering an integrated view of how relatively uniform anisotropic properties influence formability. These insights are essential for optimizing the processing and application of 2024-T3 alloy in industrial contexts, emphasizing the importance of understanding anisotropy in the design of metal components. Full article

The Royal Philanthropic Vaccine Expedition is considered in the history of medicine as the first international health expedition aimed at the global elimination of a contagious disease: smallpox. However, the initiatives carried out in this way before the arrival of the Balmis Expedition, by surgeons from the Spanish Navy, are less well known. Thus, the main objective of this research work is to offer an overview of the different anti-variolic vaccination initiatives prior to the campaign financed by the Spanish crown from these health facilities. Using the heuristic and hermeneutic method, our article is based on primary sources contrasted with specialised literature. The results obtained are presented in a narrative style from each of the surgeons identified as decisive in the implementation of the vaccine, thus providing a divergent and unpublished historiographic approach. As the facts described show, before the arrival of Balmis the vaccine substance was introduced in those countries thanks to the initiative of various surgeons: in Puerto Rico by Francisco Oller; in Cartagena and Santa Marta in Colombia by Ángel Hidalgo; in Venezuela by Alonso Ruiz; in Cuba by Tomás Romay and Bernardo de Cózar; in the Viceroyalty of New Granada (Colombia) by Lorenzo Vergés; in Guatemala by Miguel José Monzón and José María Ledesma; in the Viceroyalty of New Spain by Alejandro García Arboleya and Antonio Serrano; in Peru by Pedro Belomo; in Río de la Plata by Cristóbal Martín de Montúfar; in the Chilean region of Coquimbo by José María Gómez; and in the Philippines by Cristóbal Regidor. Finally, it should be noted that these surgeons and the approach presented are part of a historiography based on the personal actions of professionals trained, for the most part, at the Medical–Surgical School of Cadiz. Full article

Ballast is essential for vessels to lower their centre of gravity, improve stability, and ease their motion during sailing. During the modern period, heavy materials used for ballasting ships were an issue of particular concern for both authorities and ship owners, subjected to increasing control, regulation, and standardisation. These items represent a very common find in wreck sites and deserve special attention, as their characteristics, distribution, and provenance can deliver critical information for assessing where the vessel was ballasted, sailing routes, ship tonnage, and site formation processes. This article is centred on pig iron ingots, introduced in the early 18th century in sailing warships and shortly thereafter in sizeable merchant vessels, a type of ballast which is frequently overlooked in archaeological research. In particular, specimens retrieved from the Chilean Navy armed transport Infatigable (1855) were analysed through macroscopic and physicochemical characterisation using LM, SEM-EDS, WD-XRF, and IGF. The results obtained indicate the ingots were manufactured with cast iron of different quality, suggesting they may have come from different production centres. The investigation resulted in a better understanding of ballasting practices on a South American navy ship in the early post-independence period and provided new data for discussions of off-site and non-nautical technological issues, such as the materials, knowledge, and techniques associated with the production of pig iron in the mid-19th century. Full article

Four TRIP (Transformation Induced Plasticity) assisted steels, three TBF (TRIP Bainitic Ferrite) steels and one TPF (TRIP Polygonal Ferrite) steel, were manufactured from three different carbon contents (0.2, 0.3 and 0.4 wt.% C), to study the evolution of their microstructure and tensile mechanical properties in 15 mm thick plates. TBF steels were subjected to the same austenitization heat treatment and subsequent bainitization isothermal treatment. The TPF steel was subjected to an intercritical annealing and subsequent isothermal bainitization treatment. All were microstructurally characterized by optical, scanning electron and atomic force microscopy, as well as X-ray diffraction. Mechanically, they were characterized by the ASTM E8 tensile test and fractographies. For the TBF steels, the results showed that when the carbon content increased, there were an increase in volume fraction of retained austenite, of the microconstituent “martensite/retained austenite” and in the tensile strength; and a decrease in the volume fraction of bainitic ferrite matrix and elongation; with an improvement in TRIP behavior due to the increase in retained austenite. The TPF steel presented around 50% ductile polygonal ferrite developing better TRIP behavior than the TBF steels. The evolution of the fractographies was ductile to brittle for TBF steels with an increase in carbon content, and for TPF, the appearance of the fracture surface was ductile. Full article