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The increasing lifetime of the population on a world-wide scale over the last decades has led to a significant growth in the use of surgical implants for replacement of bones and teeth in affected patients. Other factors, such as scientific-technological development and more frequent exposure of individuals to trauma risk, have also contributed to this general trend. Metallic materials designed for applications in surgical implants, no matter whether orthopedic or dental, must show a group of properties in which biocompatibility, mechanical strength, and resistance to degradation (by wear or corrosion) are of primary importance. In order to reach these aims, orthopedic materials must fulfill certain requirements, usually specified in standards. These requirements include chemical composition, microstructure, and even macrographic appearances. In the present work, three cases of implant failure are presented. These cases demonstrate the most frequent causes of premature failure in orthopedic implants: inadequate surgical procedures and processing/ design errors. Evaluation techniques, including optical and scanning electron microscopy (SEM), were used to evaluate macroscopic and microstructural aspects of the failed implants, and the chemical composition of each material was analyzed. These evaluations showed that design errors and improper surgical procedures of outright violation of standards were the cause of the failures.

The development of the oil and gas industry in Brazil in the last decades has led to petroleum extraction in deeper water and extremely corrosive environments, associated to the presence of H2S, CO2 and chlorides, as well as mechanical loads caused by the wave's movement and sea streams. In these adverse conditions the search for new materials with adequate properties for this kind of application is intense.In the present work a study is carried out on the microstructure and mechanical properties of the super alloy Inconel 718 subjected to different temperatures and times of solution and aging heat treatments. This material, usually used in the fabrication of aircraft motor and energy generation turbines, in the present case is proposed for the fabrication of bolts used in the fixation of submarine pipes for oil extraction.The use of techniques like optical microscopy, automatic image analysis, scanning electron microscopy (SEM) and hardness and tensile tests, allowed the identification of the ideal conditions for heat treating this material for this kind of application.

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Metallic materials designed for applications in orthopedic or dental surgical implants must show a group of properties, including biocompatibility, mechanical strength and resistance to degradation (by wear or corrosion) outstand. In order to assure that the properties are achieved, the implant materials must fulfill certain requirements, usually specified in standards. The standards also include chemical composition, microstructure and even macrographic aspects. The main aim of this work was to perform a failure analysis on a titanium-based dental implant and connect the possible causes of failure with the associated material requirements which were previously mentioned. Evaluation techniques included metallographic analysis by optical microscopy and fractographic analysis by scanning electron microscopy (SEM). The results of the examinations suggested that, in spite of their adequate microstructures, the implants fractured due to the overload generated by stress raisers which were found in the implants.

The automotive industry is one of the most dynamic and competitive segments of the international economy and it has invested considerable resources into the research and development of new components and the improvement of existent pieces. Nonetheless, failures continue to occur, often because of defects in a component. Failure analysis uses several techniques to investigate causes of the defect which led to the failure of a component, equipment, or structure. Usually, these causes are related to the use of inadequate materials, the presence of defects which appear during fabrication or design errors, or improper assembly, maintenance and use. Knowledge about these causes and the correction of such anomalies allow the improvement of the performance of components regarding both efficiency and safety. In this study, the results of the failure analysis of the drive bar of a police car are presented and light optical microscopy and scanning electron microscopy (SEM) results are used to show that the presence of an already existent defect and an unfavorable microstructure led to the occurrence of brittle fracture which caused the premature and catastrophic failure of this component.

Inconel 718 is a widely used alloy in aircraft motor components due to a combination of some properties that are very favorable to this type of application and among these properties two ones must be emphasized: Good corrosion resistance at relatively high temperatures and adequate strength at theses temperatures. In spite of these favorable characteristics of this alloy, the normal service conditions of these components can generate damages that can hamper their use, thus leading to the necessity of weld repair in some regions of these elements. In this work, a study on the microstructural and mechanical properties characterization of the seal of an aircraft motor is carried out. With this purpose techniques such as optical microscopy, scanning electron microscopy (SEM) and microhardness were used to analyze the microstructure and mechanical properties of Inconel 718 after repair welding and aging.