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Technical Paper

Evaluation of the creep of the Ti-6Al-4V alloy with coating and atmosphere controlling

2006-11-21
2006-01-2866
The objective of this work was to evaluate the creep behavior of the Ti-6Al-4V alloy focusing on the determination of the experimental parameters related to the primary and secondary creep stages. Yttria (8 wt.%) stabilized zirconia (YSZ) with a CoNiCrAlY bond coat was atmospherically plasma sprayed on Ti-6Al-4V substrates. Constant load creep tests were conducted with Ti-6Al-4V alloy in air for coated and uncoated samples and in nitrogen atmosphere for uncoated samples at 500°C to evaluate the oxidation protection on creep of the Ti-6Al-4V alloy. Results indicated the creep resistance of the coated alloy was greater than uncoated in air, but nitrogen atmosphere was more efficient in oxidation protection.
Technical Paper

The Oxidation Effect in the Titanium Alloy at High Temperature

2007-11-28
2007-01-2814
The aim of this paper is to study of oxidation effects in creep of the Ti-6Al-4V alloy, in different atmospheres (air, nitrogen and argon). The samples were treated during 24 hours at 600°C in different atmospheres The samples treated during 24 hours at 600°C and the oxidation behavior in each atmosphere was observed. The oxidation was more aggressive in air atmosphere, forming TiO2 film in the surface. The alloy was tested in creep at 600°C in argon, nitrogen and air atmospheres using 250 MPa. The behavior of creep curves shows that useful life is better in atmospheres not so oxidant.
Technical Paper

Developing of New Titanium Alloys by Powder Metallurgy for Aerospace Applications

2003-11-18
2003-01-3605
Titanium alloys parts are ideally suited for advanced aerospace systems because of their unique combination of high specific strength at both room temperature and moderately elevated temperature, in addition to excellent general corrosion resistance. Despite these attractive features, use of titanium alloys in engines and airframes is limited by cost. The alloys processing by powder metallurgy eases the obtainment of parts with complex geometry and probably, cheaper. In this work, results of the Ti-6A1-4V, Ti-6Al-7Nb and Ti-13Nb-13Zr alloys production are presented. Samples were produced by mixing of initial metallic powders followed by uniaxial and cold isostatic pressing with subsequent densification by sintering at 1500 C, in vacuum. Sintered samples were characterized for phase composition, microstructure and microhardness by X-ray diffraction, scanning electron microscopy and Vickers indentation, respectively. Density was measured by Archimedes method.
Technical Paper

Application of Alumina Ceramic Powder in Combustion Engine Components to Thermal Insulation

2004-11-16
2004-01-3239
In a wide variety of applications, mechanical components have to operate under severe conditions, such as high load, speed or temperature and hostile chemical environment. Thus, ceramic coatings produced by thermal etching techniques are widely used for a range of industrial applications, to confer wear and erosion resistance, corrosion protection and thermal insulation. Thus, this work has as objective to deposition of the alumina ceramic powder by plasma etching in the combustion engine components (piston, valves, combustion camera), actuating such as thermal insulation to increase temperature in the combustion camera and consequently improvement of the efficiency and power. The ceramic-metal adhesion, thermal/mechanical and thermal insulation properties were evaluated by SEM and dynamometer tests, presenting promissory results related to performance and efficiency of the combustion engine recovered to ceramic powder material.
Technical Paper

Production of Ti-35Zr-10Nb Alloy by Powder Metallurgy for Automotive Application

2004-11-16
2004-01-3353
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.
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