O efeito da técnica de inclusão para fundição de titânio CP na fluidez, rusogidade, camada de reação e desajuste marginal

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência do método de processamento, sinterização convencional ou injeção a vácuo, na resistência à flexão e dureza de porcelanas feldspáticas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito de diferentes taxas de resfriamento sobre a porcelana feldspática de cobertura para infraestrutura em zircônia

Pós-graduação em Reabilitação Oral - FOAR

Tenacidade à fratura e dureza de porcelana feldspática adicionada de óxido de zircônio: efeito da concentração e da temperatura de sinterização

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Propriedades físicas e mecânicas de um cimento de ionômero de vidro após a incorporação de nanopartículas de dióxido de titânio

Pós-graduação em Ciências Odontológicas - FOAR

Caracterização mecânica de uma porcelana de aplicação convencional e uma prensada para recobrimento de infraestruturas de zircônia e o efeito do método de resfriamento na resistência à flexão biaxial do conjunto zircônia/porcelana

Pós-graduação em Reabilitação Oral - FOAR

Caracterização mecânica e microestrutural do aço MARAGING 300, soldado a plasma e submetidas a reparos

Pós-graduação em Engenharia Mecânica - FEG

Ti-Mo alloys employed as biomaterials: Effects of composition and aging heat treatment on microstructure and mechanical behavior

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A Quality Assessment of Titanium Castings Produced in an Experimental Short-Heating-Cycle Investment

The aim of this study was to evaluate the quality of casting produced in an experimental short-term heating-cycle investment. Thus, reaction layer and castability of titanium casting using an experimental spinel-based investment (VR) with short heating cycle were compared with the commercial short-heating-cycle spinel-based investment Trinell (TR), the silica-phosphate-based investment Rematitan Plus ( RP), and the conventional spinel-based investment Rematitan Ultra (RU). VR has polymeric fibers added to inorganic particles. Reaction layer assessments were carried out using Vickers hardness and elemental analysis using dispersive X-ray microanalysis (EDX). Mesh patterns were used for castability test, and powder characterization was made by scanning electron microscopy (SEM). Hardness evaluation showed no difference among the investments between 100 and 200 mu m. The most important contaminant element for VR, TR, and RU was oxygen. Higher levels of mold filling were found for TR, VR, and RU compared with that obtained with RP. The quality of castings, characterized by means of the assessments of reaction layer and castability, made from the VR was similar to the commercial investments TR and RU but superior to the RP.

Influência da potência de laser Nd: YAG na soldagem do aço inoxidável duplex UNS S32205

Pós-graduação em Engenharia Mecânica - FEIS

Estudo em fadiga no aço API 5L X80 soldado pelo processo HF/ERW

The technological advancement in order to improve the methods of obtaining energy sources such as oil and natural gas is mainly motivated by the recent discovery of oil reserves. So, increasingly , there is a need for a thorough knowledge of the materials used in the manufacture of pipelines for transportation and exploration of oil and natural gas. The steels which follow the API standard (American Petroleum Institute), also known as high strenght low alloy (hsla), are used in the manufacture of these pipes, as they have, with their welded joints, mechanical properties to withstand the working conditions to which these ducts will be submitted . The objective of this study is to evaluate the fatigue behavior in microalloyed steel grade API 5L X80 welded by process HF / ERW . For this, axial fatigue tests to obtain S-N curve (stress vs. number of cycles ) were conducted. To complement the study, it was performed metallographic , fractographic , Vickers hardness tests and tensile tests to characterize the mechanical properties of the steel and check whether the values satisfy the specifications of the API 5L standard . From the fatigue tests , it was concluded that the surface finish influences directly on the fatigue life of the material

Estudo de cerâmicas avançadas para fins de blindagem balística

The research involving new materials has always been considered as a differential in the development of a technology company. This occurred naturally since ancient times, often motivated by reasons of a certain age, where the most common material used was also the name of your time and may be cited as an example the Bronze Age, and later was the Iron. Currently, the use of firearms are they used in resolving conflicts between countries, or a more equivocal, as an instrument of social banditry make innovations in the area of shielding welcome, whether for personal use, in the form of vests or vehicle such as cars, tanks and even aircraft. In this context, is a Silicon Carbide Ceramic, with low density and high hardness. Thus, the aim of this study is the evaluation and comparison of these materials, seeking to improve their properties by means of additives such as boron and silicon metal and amorphous YAG. For this work, the specimens were pre-shaped by means of uniaxial later to be referred for isostatic pressing and sintering. The maximum percentage for each additive was 5%, except for the YAG whose percentage was 8.2% (mass percentage). All compositions were subjected to the same tests (x-ray diffraction, apparent density, optical microscopy, Vickers hardness, scanning electron Microscopita), so that one could draw a comparison between the materials under study, samples that showed better mechanical properties and micro structural, related here by hardness testing and microscopy (optical and SEM) were the silicon carbide doped with YAG and alumina samples, demonstrating the potential of these materials for ballistic protection. Other compositions have high porosity, which is highly undesirable, since in order to harmful influences on the mechanical properties discussed below

Caracterização de cerâmicas a base de nitreto de silício para aplicações estruturais

The need for development of new materials is a natural process in the companies’ technological point of view, seeking improvements in materials and processes. Specifically, among the materials, ceramic exhibit valuable properties, especially the covalent ceramics which have excellent properties for applications which requires the abrasion resistance, hardness, high temperatures, resistence, etc. being a material that has applications in several areas. Most studies are related to improvement of properties, specially fracture toughness that allows the expansion of its application. Among the most promising ceramic materials are silicon nitride (Si3N4) which has excellent properties. The goal of this work was the development and caracterization of Si3N4-based ceramics, doped with yttrium oxide (Y2O3), rar earth concentrate (CTR2O3) and cerium oxide (CeO2) in the same proportion for the evaluation of properties. The powders' mixtures were homogenized, dried and compressed under pressure uniaxial and isostatic. Sintering was carried out in 1850 ⁰C under pressure of 0,1MPa N2 for 1 h with a heating rate of 25 ⁰C / min and cooling in the furnace inertia. The characterizations were performed using Archimedes principle to relative density, weight loss by measuring before and after sintering, phase analysis by X-ray diffraction, microstructure by scanning electron microscope (SEM), hardness and fracture toughness by the method Vickers indentation. The results obtained showed relative density of 97-98%, Vickers hardness 17 to 19 GPa, fracture toughness 5.6 to 6.8 MPa.m1/2, with phases varying from α-SiAlON and β-Si3N4 depending the types of additives used. The results are promising for tribological applications and can be defined according to the types of additives to be used

Dureza e rugosidade superficial de cimentos de ionômero de vidro após ensaio de escovação

To evaluate the surface roughness and Vickers hardness of glass ionomer cements Ketac Molar® and Ketac Molar Easy Mix® (ESPE Dental AG) after brushing. Methods – After roughness and hardness tests of 14 specimens of each material, they were submitted to 30,000 brushing cycles and new analysis of roughness and hardness. Statistical analysis showed that there was no significant difference between the materials in relation to the initial roughness. Results – However, after brushing there was higher surface roughness for Ketac Molar Easy Mix®. For both materials, there was increase of hardness after brushing and the highest values were presented by Ketac Molar Easy Mix®. Conclusion – It can be concluded that, when choosing a glass ionomer cement for restoration it should be preferred to Ketac Molar, because it showed hardness similar to Ketac Molar Easy Mix, but it was less rough.

Addition of Chlorhexidine Gluconate to a Glass Ionomer Cement: A Study on Mechanical, Physical and Antibacterial Properties

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)