Vickers Hardness
Mostrando 13-24 de 165 artigos, teses e dissertações.
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13. Softening Behavior During Annealing of Overaged and Cold-rolled Aluminum Alloy 7075
This work proposes studying the softening kinetics of aluminum alloy 7075-T6. Firstly, AA 7075 strips were overaged (300°C and 5 hours). Then, the overaged strips were cold-rolled at room temperature (45% in thickness reduction) and, after that, annealed at different temperatures (200°C and 250°C) and time intervals (30 minutes - 4 hours). By using polari
Mat. Res.. Publicado em: 30/05/2019
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14. Boriding and boronitrocarburising effects on hardness,wear and corrosion behavior of AISI 4130 steel
ABSTRACT The effects of boriding and boronitrocarburising surface treatments on the microstructure and mechanical properties of AISI 4130 steel have been investigated. Pack boriding was carried out at 1223 K for 5 h and 8 h, while the double treatment of boronitrocarburising consisted of salt bath nitrocarburising at 853 K for 6 h followed by pack boriding a
Matéria (Rio J.). Publicado em: 20/05/2019
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15. Microstructure and Wear Resistance of ZrC-ZrB2 /Ni Composite Coatings Prepared by Plasma Transferred Arc Cladding
The ZrC-ZrB2/Ni metal matrix composite coatings were in-situ synthesized from a mixture of Ni, Zr and B4C by plasma transferred arc (PTA) cladding process. Microstructures and phase constituents of the coatings were characterized by electron probe micro-analyzer (EPMA) and X-ray diffraction (XRD). Microhardness and wear resistance of the coatings were system
Mat. Res.. Publicado em: 06/05/2019
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16. Brittleness index and its relationship with materials mechanical properties: Influence on the machinability of CAD/CAM materials
Abstract: The aim of this study is to evaluate the machinability of four CAD/CAM materials (n = 13) assessed by brittleness index, Vickers hardness, and fracture toughness and interaction among such mechanical properties. The materials selected in this in vitro study are Feldspathic ceramic [FC], Lithium-disilicate glass ceramic [LD], leucite-reinforced glas
Braz. oral res.. Publicado em: 04/04/2019
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17. Nickel-Titanium Alloys Welding of Thin Sheets Using GTAW: Comparative Study Between Similar and Dissimilar Welding with AISI 304 Stainless Steel
The objective of the present work was to evaluate welding of thin sheets (thickness < 1 mm) of similar and dissimilar NiTi alloys with AISI 304 stainless steel using the Gas Tungsten Arc Welding (GTAW) process and to study the mechanical and metallurgical properties of the joints with and without post-welding heat treatment (PWHT). The GTAW process was chose
Mat. Res.. Publicado em: 08/11/2018
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18. Can heat-pressed feldspathic ceramic be submitted to multiple heat-pressing?
Abstract The aim of this study was to determine if multiple processing (heat-pressing) of a dental ceramic influences flexural strength, hardness, and microstructure. Ninety bar-shaped specimens (15 mm × 4 mm × 2 mm) of a pressed ceramic (Vita PM9) were fabricated and randomly divided into 6 groups (n = 15) according to the factors “number of pressings�
Braz. oral res.. Publicado em: 25/10/2018
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19. Physicomechanical characterization and biological evaluation of bulk-fill composite resin
Abstract The aim of this study was to evaluate the cytotoxic effect, degree of conversion (% DC), Vickers hardness (VH), and surface morphology of composite resins. Eleven resins, nine bulk-fill resins, and two conventional resins were evaluated. Each material was sampled to evaluate DC (using FTIR), VH, cytotoxicity (using MTT and Neutral Red - NR test), su
Braz. oral res.. Publicado em: 25/10/2018
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20. Effect of Solidification Processing Parameters and Silicon Content on the Dendritic Spacing and Hardness in Hypoeutectic Al-Si Alloys
Aluminium with silicon as alloying element, form a class of material providing the most significant part of all material casting manufactured materials. These alloys have a wide range of applications in the automotive and aerospace industries. It is widely recognized that moderate addition of silicon to aluminum, significantly improves the resulting mechanic
Mat. Res.. Publicado em: 17/09/2018
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21. Effect of Hot Deformation on Microstructure, Hardness and Precipitation Kinetics in a C350 Maraging Steel Modified by Titanium Addition
Maraging steels are alloys with a good balance between strength and fracture toughness. These properties are obtained by quenching and aging treatments, where the precipitation of intermetallic compounds is promoted in a martensitic matrix. In this context, this paper aims to evaluate the effect of hot deformation on microstructure, kinetics and formation of
Mat. Res.. Publicado em: 17/09/2018
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22. Extensión de durabilidad de pistones de bombas de fractura hidráulica mediante el empleo de tecnología de nitruración por plasma y PVD
ABSTRACT Hydraulic stimulation technique consists of "fracturing" the formation (rock reservoirs) through pumping a fracturing fluid downhole. This operation is performed by using hydraulic fracturing pumps. The pistons of these pumps are mechanical components performing the intake and compressing fracture fluid by reciprocating action. During this alternati
Matéria (Rio J.). Publicado em: 19/07/2018
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23. Optimización del proceso RSW para acero DP 1000
ABSTRACT In recent times new materials have been introduced in automobiles construction in order to reduce their weight and consequently fuel consumption and emissions level. Among them are Dual Phase (DP) steels, constituted by a ferritic matrix with martensite islands. Resistance Spot Welding (RSW) is the most commonly used welding process in the automotiv
Matéria (Rio J.). Publicado em: 19/07/2018
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24. Caracterización del comportamiento frente a la corrosión en soldaduras de recargue de aceros inoxidables superdúplex
ABSTRACT Superduplex stainless steels have a dual structure constituted approximately by 50% of ferrite and 50 % of austenite. This fact produces a good combination of mechanical properties and corrosion resistance. Thanks to these features their use is growing, mainly in the industries of paper, chemical, gas and oil. Surfacing welding is used for the manuf
Matéria (Rio J.). Publicado em: 19/07/2018