Modifying the surface of titanium alloys with a laser considerably increases the specific area, which has beneficial implications for the osseointegration process. In this study, Yb:YAG laser was used to modify the surface of the commercial β-type Ti-15Mo alloy. The process parameters used were based on a suitable osseointegration condition for this treatment. The effect of such modification on the fatigue performance of the alloy was analyzed. To assess the impact of surface modification on the alloy’s fatigue performance, axial fatigue tests were conducted on specimens with both polished and laser-modified surfaces (R = 0.1). Fatigue strength was evaluated using a staircase method, where specimens were subjected to varying maximum stress levels to determine the fatigue limit after 5x106 cycles. The results showed that the laser-modified surface presented cavities and roughness values such that the effect on fatigue was highly detrimental. A reduction of around 75% in the fatigue limit (maximum stress) was obtained, indicating that modifying the Ti-15Mo alloy with laser for medical purposes may require integrated biological-mechanical development. area study YbYAG Yb YAG βtype β type Ti15Mo TiMo Ti 15Mo Mo treatment analyzed s lasermodified modified R 0.1. 01 0.1 . 0 1 0.1) method x 5x10 cycles detrimental 75 obtained biologicalmechanical biological mechanical development 0. 5x1 7 5x

Abstract Paper aims This paper aimed to analyze the level of involvement of companies in the state of São Paulo with aspects of occupational health and safety (OH&S) and with NBR ISO 45001:2018. OH&S aspects have acquired increasing prominence worldwide especially due to the unprecedented publication of ISO 45001 in 2018. Originality To the authors’ knowledge, this is the first paper published in Brazil to explore the applicability of ISO 45001 to Brazilian companies. Research method A survey was structured based on the requirements of the standard and sent to a sample of companies. After data collection and analysis, interviews were conducted with some of the companies as a way to complement and specify the data obtained. Main findings OH&S operations with a management approach mostly occur in large companies. Small and medium-sized companies also work on OH&S aspects, however with specific actions oriented towards the compliance with Regulatory Standards by the Ministry of Labor. The knowledge about ISO 45001 proved to be still incipient. Implications for theory and practice Since very few companies have performed some kind of work in order to bring the requirements of ISO 45001 to the organizational environment, new gaps must be filled concerning OH&S aspects.

The effect of a surface treatment by Nd:YAG laser irradiation on the fatigue behavior of Ti-6Al-4V ELI was studied. Axial fatigue tests were performed to obtain S-N curves in polished and laser treated conditions. Roughness measurements and scanning electron microscopy were used to characterize the features of the modified surface. A reduction in the fatigue strength of around 35% was obtained after the laser treatment of the material surface. Although the surface roughness was in the micrometer scale, a notch effect was suggested to be the reason for the deleterious influence of the laser on the fatigue strength. The reduction in the fatigue strength obligatory demands redesign of implants for laser modified surfaces of Ti-6Al-4V alloy.

The objective of this investigation was to evaluate the influence of surface modification by femtosecond laser (with average fluence of 0.6 J/cm2 and scanning speed of 0.1 mm/s) on the fatigue resistance of Ti-6Al-4V ELI alloy. A significant reduction in the fatigue strength of the material modified by laser was observed. Residual tensile stresses generated during surface modification were negligible, presenting lower values than those found on the unmodified surface. Based on a recently developed and published prediction model, the reduction of the fatigue strength was ascribed to the surface roughness created during the laser treatment of the alloy. An evidence was that the fatigue crack nucleation occurred in the modified region, rather than at the edge of the rectangular specimens as in the untreated condition.

Nanotechnology is seeing as having potential to raise benefits to several research and application areas. Recently materials with nanostructured surfaces of nanopores, nanotubes and nanowires have become an important investigation field, since their chemical and physical properties may be substantially different from those of the corresponding substrate. In face of the necessity of assuring that such modifications are not deleterious to the mechanical behavior, the purpose of this work was to evaluate the fatigue performance of CP-Ti grade 2 with the surface modified by the formation of nanotubes on their different crystalline structures. The nanotubes layers were produced by anodic oxidation using a potential of 20V during 1h and a solution of glycerol, H2O and NaF, and analyzed by scanning electron microscopy. In order to obtain the anatase and rutile structures, annealing treatments were respectively performed at 450°C and 650°C. The axial fatigue tests were conducted in physiological solution at 37°C following the stepwise load increase approach. When compared to the material without surface modification (polished surface), the results showed that the anatase phase did not affect the fatigue response, maintaining the fracture stress in 500 MPa, whereas the rutile phase caused a decrease to 450 MPa.

A soldagem por fricção por ponto (FSpW) é um processo de soldagem no estado sólido adequado para a produção de juntas pontuais, especialmente em materiais leves, que são particularmente interessantes devido ao potencial de redução de peso. A penetração de uma ferramenta não-consumível e rotacional especialmente desenvolvida cria uma junção entre as placas sobrepostas através de calor por fricção e deformação plástica. A perda de material é mínima, obtendo-se, portanto, uma junta totalmente consolidada com superfície plana (sem furo). Neste trabalho, investigou-se o efeito dos parâmetros do FSpW, tais como velocidade de rotação, profundidade de penetração e tempo de residência, na resistência ao cisalhamento das juntas de liga de magnésio AZ31. A otimização dos parâmetros de entrada do processo foi realizada através do método de Taguchi de DOE. A análise de variância foi aplicada para determinar a importância individual de cada parâmetro. Os gráficos dos efeitos principais foram utilizados para indicar os melhores níveis que maximizam a resistência ao cisalhamento. Os resultados mostram que a profundidade de penetração da ferramenta possui a maior influência sobre a resistência da solda, seguida da velocidade de rotação e tempo de residência.

Friction spot welding (FSpW) is a solid state welding process suitable for producing spot-like joints, especially in lightweight materials, which are particularly interesting due to the weight saving potential. The plunging of an especially designed non-consumable and rotating tool creates a connection between overlapped sheets through frictional heat and plastic deformation. Minimum material loss is observed, and therefore a fully consolidated joint with flat surface (no keyhole) is obtained. In the current study, the effect of FSpW parameters, such as rotational speed, plunge depth and dwell time, on lap shear strength of AZ31 magnesium alloy joints was investigated. The optimization of input process parameters was carried out through Taguchi approach of DOE. Analysis of variance was applied to determine the individual importance of each parameter. Main effect plots were used to indicate the best levels for maximizing lap shear strength. The results show that tool plunge depth has the higher effect on the weld strength, followed by rotational speed and dwell time.

A recente preocupação quanto às mudanças climáticas vem impulsionando pesquisas em eficiência energética dos meios de transportes no sentido de reduzir a emissão de gases. Uma das principais soluções consiste na redução do peso estrutural através da aplicação de novos materiais, como as ligas leves de alumínio e magnésio. Entretanto, novos usos ficam muitas vezes limitados pela dificuldade de união desses materiais. A técnica de soldagem por fricção e mistura (FSW) é um processo de união no estado sólido que surge como uma alternativa viável para substituir ou complementar as tecnologias de união consagradas. Como uma junta contínua não é sempre a requisitada, duas tecnologias de união por ponto derivadas do FSW estão em desenvolvimento: soldagem por fricção e mistura por ponto (FSSW) e soldagem por fricção por ponto (FSpW). Além de fornecerem juntas de elevada resistência e praticamente isentas de defeitos, estas técnicas apresentam alta eficiência energética, curto ciclo de soldagem, facilidade de automação e compatibilidade com o meio-ambiente, fazendo frente às técnicas convencionais de união por ponto, como a soldagem por resistência por ponto (RSW) e a rebitagem.

The recent concern about climate change has stimulated research into transport energy efficiency in order to reduce the emission of gases. One of the main solutions is to reduce the structural weight through the application of new materials, such as aluminum and magnesium lightweight alloys. However, new applications are often limited by the difficulty of joining these materials. Friction Stir Welding (FSW) is a solid state joining technique that emerges as a viable alternative to replace or complement the established joining technologies. As a continuous weld is not always requested, two spot welding technologies derived from FSW are under development: Friction Stir Spot Welding (FSSW) and Friction Spot Welding (FSpW). Besides providing almost defect-free and high strength joints, these techniques exhibit high energy efficiency, short welding cycle, ease of automation and environmental compatibility, competing against the conventional spot joining techniques, such as Resistance Spot Welding (RSW) and riveting.