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This study aims to determine some mechanical properties of an Inconel 718 aged superalloy obtained through hot tensile tests. These properties as conventional 0.2% yield strength (σv), ultimate strength (σUTS), and specific elongation assessment (εu) are important parameters in the study of the mechanical material behavior. The superalloy was subjected to hot tensile tests at 650 to 700°C and a strain rate of 0.5 mm/min according to ASTM E-8. It is used a scanning electron microscope (SEM) to obtain images of the fracture surface of the specimens. The images of the fracture surface are analyzed in order to relate the temperature of the test with the type of mechanism of fracture.

This work intends to analyze the influence of the stress and temperatures used in creep mechanical tests in the types of fractures that occurred in the superalloy Inconel 718. For this, the superalloy was subjected to creep tests under the conditions 625 to 814 MPa at temperatures of 650, 675 and 700°C. After the tests, the fractured samples were cleaned on an ultrasound and subjected to microstructural analysis using the technique of scanning electron microscopy. Images were performed with different increases in order to analyze the type of fracture that occurred in the material. The elongated sample and its reduction in area were also measured in order to study the effects of different conditions used in the creep tests under material's fracture.

The automotive industry has identified several automobile components that could be replaced with titanium alloy components, either through direct replacement in existing designs or, preferably, in new designs to fully exploit the unique properties of titanium. The alloy processing by powder metallurgy (M/P) eases the obtainment of parts with complex geometry and, probably, cheaper. In this work, results of the Ti-35Zr-10Nb alloy production are presented. This alloy due to its high wear, impact and corrosion resistance is a promising candidate for automotive applications. Samples were produced by mixing of initial metallic powders followed by uniaxial and cold isostatic pressing with subsequent densification by sintering between 900-1400 °C, in vacuum. Sintering behavior was studied by means of dilatometry. Sintered samples were characterized for phase composition, microstructure and microhardness by X-ray diffraction, scanning electron microscopy and Vickers indentation, respectively.

In this work five methods of heat treatments are investigated in order to obtained convenient volume fractions of ferrite, bainite, martensite and retained austenite, starting with a low carbon steel and seeking the distinction of the phases, through optical microscopy. Specific chemical etching is improved. The results in tensile and fatigue tests were accomplished and the results were related with the microstructural parameters. The results show that the mechanical properties are closely related with the phases, grains size and the phases morphology.

The aim of this paper is to analyze the microstructural development in samples of Ti-48Al-2Cr-2Nb (at.%) alloys obtained by powder metallurgy (P/M). This alloy has potential applications when high operating temperatures are required, e. g. turbines, aerospace applications, automotive engines valves and turbocharger rotors. The elementary powders were mixed for 1 hour, cold uniaxially pressed at 60 MPa and sintered at 1100°C, for 1 hour, under vacuum. Then, the specimens were milled and submitted to a second stage that included cold isostatic pressing (400 MPa) with subsequent hot uniaxial pressing (20 MPa), between 900 up to 1200°C, for 2 hours, in argon atmosphere. The alloys were characterized by XRD (X-ray diffraction), SEM (Scanning Electron Microscopy), EDS (Energy Dispersive Spectroscopy) and Vickers microhardness measurements. The results indicated the viability of the route and the tendency of a lamellar microstructure in high sintering temperatures.

The present study concerns laser surface nitriding of Ti-6Al-4V. The Ti-6Al-4V alloy was submitted a superficial treatment of pulsed laser Nd:YAG (λ=1.064 μ\m) in atmosphere of 40wt% nitrogen-60wt% argon. The samples were characterized by optical microscopy and electron scanning microscopy. The microstructure of the surface nitrided Ti-6Al-4V consists of TiN dendrites distributed in α--Ti matrix. It can be noted that there is a significant enhancement in surface roughness after surface nitriding (6.60 μm) as compared to the as received Ti-6Al-4V (0.46 μm). The microhardness of the surface is improved to 1100 VHN as compared to the 340 VHN of substrate.

The study of creep has a major importance when materials are submitted to high stress and homologous temperature. Superalloys are designed to operate under high stress, temperature and corrosion environment. Those properties of superalloys are due to high temperature stable matrix, solid solution elements and precipitated particles. This study aims to determine the creep resistance of Inconel 718 aged superalloy obtained through the tests according to ASTM E139-06, at stress range of 510 to 700 MPa and temperature of 675°C. The parameters as the primary creep time (tp), steady-state creep rate (εs), time to rupture (tr) and strain to rupture (εr) are important to evaluate the creep resistance. It used a scanning electron microscope (SEM) to obtain images of the fracture surface of specimens. The images of the fracture surface were investigated in order to relate the temperature of test with the fracture mechanism.

Materials with appropriate behavior at high temperatures and aggressive environments have become a scientific and technological necessity nowadays. Studies have been undertaken for improvement in getting new alloys, especially for the reevaluation of existing commercial alloys, through the acquisition of data under conditions of higher severity. In this context it was used for this work to Ti-6Al-4V in the form of cylindrical bars, provided forged and annealed at 190°C for 6 hours and cooled in air, which has favorable properties for aerospace application. The alloy after heat treatments to obtain the bimodal structures, martensite and Widmanstätten was subjected to creep tests at 600°C under the conditions of 250 and 319 MPa, in the form of constant load. The structures of Widmanstätten and martensite showed higher creep resistance in both stress conditions used in the trials.

CVD diamond film deposition on WC-Co substrate is the most likely application of diamond CVD technology towards large scale production, due to its suitability to aluminium alloys machining in the automotive and aerospace industry. Several film-substrate interfaces and surface modifications have been developed aiming higher levels of simultaneous diamond film-substrate adherence and substrate surface toughness, however the results are still far bellow industry requirements for widen scale application. In this work a new interface is introduced in the CVD diamond films technology, which consists of a thermo-reactive deposited and diffused vanadium carbide layer, highly adequate to diamond films deposition on cemented carbide cutting and forming tools. This interface presents good diamond growth characteristics, thermal expansion coefficient similar to the substrate and, in addition, high hardness and mechanical strength.