EFFECT OF SURFACE ALUMINIZING ON LONG-TERM HIGH-TEMPERATURE THERMAL STABILITY OF TC4 TITANIUM ALLOY

2016 ◽  
Vol 23 (02) ◽  
pp. 1550102 ◽  
Author(s):  
JINGJIE DAI ◽  
JIYUN ZHU ◽  
LEI ZHUANG ◽  
SHOUYING LI
Keyword(s):  
High Temperature ◽  
Glow Discharge ◽  
High Temperature Oxidation ◽  
Room Temperature ◽  
Discharge Plasma ◽  
Glow Discharge Plasma ◽  
Ti Alloy ◽  
High Temperature Stability ◽  
Temperature Oxidation

Aluminum (Al)–rich titanium (Ti)–Al alloyed coating was fabricated on the surface of TC4 Ti alloy to improve the high-temperature stability of TC4 Ti alloy by means of arc-added glow discharge plasma technology. Microstructure, room-temperature properties and long-term high-temperature oxidation behavior of the alloyed sample were investigated. The results show that a uniform and compact Ti–Al alloyed coating with about 30[Formula: see text][Formula: see text]m thickness formed on the surface of TC4 Ti alloy. Microhardness and room-temperature wear resistance of the alloyed sample improved significantly. Long-term oxidation behaviors of the samples in air at 800[Formula: see text]C for 1000[Formula: see text]h show that the mass gain of the alloyed sample was 0.3686[Formula: see text]mg/cm2, while that of the substrate was 18.2095[Formula: see text]mg/cm2. Arc-added glow discharge plasma aluminizing improved high-temperature oxidation resistance of TC4 Ti alloy significantly.

Increased High Temperature Oxidation Resistance of Ni20Cr20Fe5Nb1Y2O3 Alloy with Nano-Sized Grains

2005 ◽  
Vol 486-487 ◽  
pp. 109-112 ◽  
Author(s):  
Il Ho Kim ◽  
S.I. Kwun
Keyword(s):  
Tensile Strength ◽  
High Temperature ◽  
Mechanical Alloying ◽  
Tensile Properties ◽  
Oxidation Resistance ◽  
Tensile Property ◽  
High Temperature Oxidation ◽  
Room Temperature ◽  
Dispersion Strengthening ◽  
Temperature Oxidation

The oxidation and tensile properties of a Ni20Cr20Fe5Nb alloy and a Ni20Cr20Fe 5Nb1Y2O3 alloy with nano-sized grains were compared with those of the comercial IN718 alloy. The oxidation resistance of the Ni20Cr20Fe5Nb1Y2O3 alloy was superior to that of the Ni20Cr20Fe5Nb and IN 718 alloys. This superior oxidation resistance was the result of both the formation of dense oxides on the surface of the alloy and the interruption of Cr migration in the alloy by the addition of Y2O3. Moreover, the tensile property of the Ni20Cr20Fe5Nb1Y2O3 alloy at room temperature and 400oC was higher than that of the Ni20Cr20Fe5Nb and IN718 alloys by more than 300MPa (30%). This result can be attributed to the dispersion strengthening of Y2O3. The relatively low tensile strength at 600°C and 800°C of the alloys fabricated by mechanical alloying was attributed to grain refinement showing intergranular fracture at high temperatures.

High Temperature Oxidation and Corrosion of Silicon-Based Non-Oxide Ceramics

1999 ◽  
Vol 122 (1) ◽  
pp. 13-18 ◽  
Author(s):  
H. Klemm ◽  
M. Herrmann ◽  
C. Schubert
Keyword(s):  
High Temperature ◽  
Elevated Temperatures ◽  
Microstructural Analysis ◽  
Temperature Stability ◽  
Ambient Air ◽  
High Temperature Stability ◽  
Temperature Oxidation ◽  
Sic Ceramics ◽  
Silicon Based

The present study is focussed on the oxidation behavior of nonoxide silicon-based ceramics. Various Si3N4 and SiC ceramics were examined after long term oxidation tests (up to 5000 h) at 1500°C in ambient air. The damage mechanisms were discussed on the basis of a comprehensive chemical and microstructural analysis of the materials after the oxidation tests. The diffusion of oxygen into the material and its further reaction in the bulk of the material were found to be the most critical factors during long term oxidation treatment at elevated temperatures. However, the resulting damage in the microstructure of the materials can be significantly reduced by purposeful microstructural engineering. Using Si3N4/SiC and Si3N4/MoSi2 composite materials provides the possibility to improve the high temperature stability. [S0742-4795(00)00301-X]

scholarly journals Evaluation of the Effect of Glow Discharge Plasma Surface Treatment on Bonding Cements to Zirconia

2018 ◽  
Vol 12 (1) ◽  
pp. 846-855
Author(s):  
Abdulelah M. Binmahfooz ◽  
Ghadeer I. Basunbul ◽  
Aws S ArRejaie
Keyword(s):  
Glow Discharge ◽  
Surface Treatment ◽  
Discharge Plasma ◽  
Glow Discharge Plasma ◽  
Cohesive Failure ◽  
Luting Agent ◽  
Plasma Surface Treatment ◽  
Adhesion Failure ◽  
Alternative Solutions

Background: The major difference in the chemical composition of Y-TZP ceramics, as compared with conventional porcelain, led researchers to develop alternative solutions for achieving durable and long term bonding with the zirconia surface. Objective: The study aims to evaluate the effects of glow discharge treatment on the bonding between cement and zirconia. Methods: The zirconia rings and rods were prepared with the Zirconia Y-TZP powder and TZ-3YSB-E (Tosoh-Zirconia) through auto-mix to investigate the glow discharge and thermo-cycling. An orientation Teflon mold was used to centralize each rod into the zirconia ring, and aided as a cementation jig during the cementation procedure. Results: Cohesive failure (2/3 or more of luting agent remained on the zirconia surface) has been majorly observed with RelyX Ultimate, while adhesion failure (less than 1/3 of the luting agent remained on the zirconia surface) has been primarily observed in Ketac-Cem. Mixed failure was observed among the three specimen including Rely X Unicem 2, Multilink Auto-mix and Ceramir. Conclusion: The glow discharge surface treatment procedure had a major impact on bond strength to zirconia.

scholarly journals HIGH TEMPERATURE OXIDATION OF TI-6AL-4V ALLOY FABRICATED BY ADDITIVE MANUFACTURING. INFLUENCE ON MECHANICAL PROPERTIES

2020 ◽  
Vol 321 ◽  
pp. 03006
Author(s):  
Antoine CASADEBAIGT ◽  
Daniel MONCEAU ◽  
Jonathan HUGUES
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Additive Manufacturing ◽  
Titanium Alloys ◽  
Oxidation Kinetics ◽  
High Temperature Oxidation ◽  
Effect Of Temperature ◽  
Premature Failure ◽  
Temperature Oxidation

Titanium alloys, such as Ti-6Al-4V alloy, fabricated by additive manufacturing processes is a winning combination in the aeronautic field. Indeed, the high specific mechanical properties of titanium alloys with the optimized design of parts allowed by additive manufacturing should allow aircraft weight reduction. But, the long term use of Ti-6Al-4V alloy is limited to 315 °C due to high oxidation kinetics above this temperature [1]. The formation of an oxygen diffusion zone in the metal and an oxide layer above it may reduce the durability of titanium parts leading to premature failure [2, 3]. In this study, Ti-6Al-4V alloy was fabricated by Electron Beam Melting (EBM). As built microstructure evolutions after Hot Isostatic Pressure (HIP) treatment at 920 °C and 1000 bar for 2h were investigated. As built microstructure of Ti-6Al-4V fabricated by EBM was composed of Ti-α laths in a Ti-β matrix. High temperature oxidation of Ti-6Al-4V alloy at 600 °C of as-built and HIP-ed microstructures was studied. This temperature was chosen to increase oxidation kinetics and to study the influence of oxidation on tensile mechanical properties. In parallel, two other oxidation temperatures, i.e. 500 °C and 550°C allowed to access to the effect of temperature on long-term oxidation.

Arc-Spraying Composite Coatings on Mild Steel for Long-Term High-Temperature Oxidation Protection

2013 ◽  
Vol 690-693 ◽  
pp. 2039-2045
Author(s):  
Zhong Li Zhang ◽  
Qi Shen Wang ◽  
Peng Rao Wei ◽  
Xue Gong
Keyword(s):  
High Temperature ◽  
High Temperature Oxidation ◽  
Protective Coatings ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Arc Spraying ◽  
Al Alloy ◽  
Temperature Oxidation ◽  
Oxidation Protection

An arc-spraying composite coating system for high-temperature oxidation protection is composed of an inner Fe-Cr-Al alloy layer and an Al-Si alloy outer layer. The high-temperature oxidation behavior of the composite coatings on steel substrate was studied during isothermal exposures in air at 900°C. Experiments show that the coatings on steel substrate are not deteriorated and the substrate is protected well, being exposed to high temperatures up to 900°C. Inter diffusion of alloying elements within the protective coatings occur, while the elements, Cr and Al, are also diffusing to the core of the base metal. As test time proceeds, a large number of chromium oxides are generated in situ within the protective coatings, especially close to the coating/substrate interface. The oxides generated increase the bond strength of the coating to the steel substrate, and together with the surface alumina they provide a long-term effective anti-oxidant protection to steel substrate. The results on titanium sponge production site show that the protective coatings on the reactor have provided an effective protection and prolong the lifetime at least forty percent for the reactors.

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