Powder bed fusion technology has undergone a remarkable amount of development in recent years in the field of medical implants due to the advantages associated with it. In many implant applications that demand loads in parts with a high degree of roughness and small dimensions, the mechanical properties, especially fatigue properties, play a key role in the success of the implants. One of the most used materials in this field is Ti-6Al-4V. On the other hand, the high cost of titanium powders makes it necessary to search for suitable powder recycling strategies. In this work, the effects of dimensions and powder recycling on the roughness and the mechanical properties of cylinder specimens were obtained from tensile static and fatigue tests of Ti-6Al4V Extra-Low Interstitial (ELI) parts. Four types of specimens were fabricated by laser powder bed fusion (two dimensions (section diameters of 2 mm and 5 mm) with new powder and with recycled powder). Results show that the oxygen concentration increased with recycling. No significant effects of recycling were observed on the monotonic tensile strength specimens. However, specimens fabricated with recycled powder showed greater roughness, lower ductility, and lower fatigue strength than those fabricated with new powder. On the other hand, the 5-mm-diameter specimens showed slightly better fatigue behavior than the 2-mm-diameter ones.

This paper presents preliminary results in determining the optimum parameters for graffiti removal in a ornamental granite, Rosa Porriño, by means of Nd:YVO4 laser at the wavelength of 355 nm and different fluences. The spray-paints (black, blue, red and silver) tested in this work were chemically characterized by means of elemental analysis, XRF, SEM/EDX and FTIR. The assessment of cleaning and characterization of the stone substrate before and after irradiation was performed by means of optical microscopy, SEM-EDX, and confocal microscopy. The analysis of the irradiated samples showed in some cases, damage in the granite substrate associated to thermal effects. The severity and kind of damage, depends on the laser fluence delivered, the constituent mineral irradiated, and the color used to paint the stone. So, at the highest levels of fluence the laser beam is able to scratch the surface, being the depth of the grooves in the stone measured by confocal microscopy. Moreover, SEM images show the differential damage caused in mineral constituents of granite i.e., quartz, feldspars, and biotite, the latter providing to be the most affected mineral, reaching melting even at low levels of fluence. It was appreciated that the color of the spray-paint affects the results of cleaning, and observed differences could be attributed to different organic constituents in the paints or the presence of metallic particles in its composition, as occurs with silver paint.

Thoracic reconstructions are essential surgical techniques used to replace severely damaged tissues and restore protection to internal organs. In recent ye