Interface Modification for Fiber-Reinforced Titanium Aluminide Composites

1990 ◽  
Vol 194 ◽  
Author(s):  
Daniel E. Boss ◽  
J. M. Yang
Keyword(s):  
Heat Treatment ◽  
Silicon Carbide ◽  
Aluminum Oxide ◽  
Titanium Carbide ◽  
Titanium Diboride ◽  
Titanium Aluminide ◽  
Chemical Vapor ◽  
Silicon Carbide Fiber ◽  
Gamma Titanium Aluminide ◽  
Before And After

AbstractCandidate diffusion barrier coatings were applied to aluminum oxide and silicon carbide fibers, and consolidated in a gamma titanium aluminide alloy. Interfacial coatings of titanium carbide and titanium diboride were applied to the fibers using chemical vapor deposition, while calcium oxide coatings were applied from a solution. Sections of these specimens were vacuum encapsulated in quartz tubing and heat treated for 50 hours at 1100°C. The thermochemical stability of the fibers was evaluated using energy dispersive x-ray spectroscopy to compare the fiber-matrix interface of the specimens before and after heat treatment. Both the as-manufactured and the coated aluminum oxide fibers showed no discernable interaction with the titanium aluminide matrix. Titanium diboride effectively prevented the silicon carbide fiber from reaction with the matrix. The silicon carbide fiber which was coated with titanium carbide showed significant reaction between the fiber and the coating after heat treatment.

Application of chemical vapor deposited yttria for the protection of silicon carbide fibers in a SiC/Ni3Al composite

1990 ◽  
Vol 5 (11) ◽  
pp. 2706-2717 ◽  
Author(s):  
D. J. Larkin ◽  
L. V. Interrante ◽  
A. Bose
Keyword(s):  
Silicon Carbide ◽  
Nickel Aluminide ◽  
Chemical Vapor ◽  
Degradation Process ◽  
Auger Spectroscopy ◽  
Silicon Carbide Fibers ◽  
Sic Fiber ◽  
Chemical Vapor Deposited ◽  
Volatile Products ◽  
Before And After

A CVD process has been developed for coating Textron-Avco SCS-6 SiC fiber with yttria. Both Y(fod)3·H2O and Y(thd)3 (fod = 1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octanedionato; thd = 2,2,6,6-tetramethyl-3,5-heptanedionato) were examined as potential Y2O3 CVD precursors. Analysis of the deposits by Auger spectroscopy indicated significant F and C'incorporation in the case of Y(fod)3 · H2O whereas, under appropriate conditions, Y(thd)3 gave a deposit which was essentially free of C and other impurities. GCFTIR analysis of the volatile products of the CVD process indicated isobutylene, tetrafluoroethylene, 1,1-difluoroethylene, fluoroform, and fluoroethylene for Y(fod)3 · H2O and mainly isobutylene and propylene for Y(thd)3. The precursor Y(thd)3 was chosen to deposit 1–2 μm of yttria on short lengths of silicon carbide fibers. The coated fibers were then incorporated into a nickel aluminide (Ni3Al) matrix by reactive sintering, with yttria affording protection from the known SiC + 2Ni ⇉ Ni2Si + C degradation process. The SiC/Ni3Al composites, before and after annealing at 1000 °C for up to 100 h, were studied by using SEM and EMPA to determine the extent of reaction. With the exception of certain portions of the fibers that were inadequately coated with yttria, complete protection of the fibers was indicated.

Preparation of Zirconia Coatings on Silicon Carbide Fiber by Metal Organic Chemical Vapor Deposition

2021 ◽  
Vol 57 (3) ◽  
pp. 269-274
Author(s):  
V. E. Prokip ◽  
V. V. Lozanov ◽  
D. A. Bannykh ◽  
N. B. Morozova ◽  
N. I. Baklanova
Keyword(s):  
Silicon Carbide ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Silicon Carbide Fiber ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

Effect of Heat Treatment on the Microstructure and Mechanical Properties of Cf/SiC Composites

2007 ◽  
Vol 336-338 ◽  
pp. 1291-1293
Author(s):  
Xin Gui Zhou ◽  
Chang Cheng Zhou ◽  
Chang Rui Zhang ◽  
Ying Bin Cao ◽  
Shi Qin Zou
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Fracture Toughness ◽  
Silicon Carbide ◽  
Shear Strength ◽  
Carbon Fiber ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Carbon Coatings ◽  
Sic Composites

3D braided carbon fiber reinforced silicon carbide (3D-Cf/SiC) composites were fabricated by precursor infiltration and pyrolysis(PIP), with carbon coatings prepared by chemical vapor deposition (CVD) before PIP. The effect of 1873K heat treatment on the mechanical properties of Cf/SiC composites were investigated. The results showed that heat treatment before PIP can increase the density of composites and lead to excellent properties of Cf/SiC composites. The flexual strength of the Cf/SiC composites with one cycle of 1873 K heat treatment reached 571 MPa, shear strength 51 MPa, and fracture toughness 18 MPa⋅m1/2.

The Microstructure, Creep, and Hardness Properties of Powder Metallurgy Beta Gamma TiAl-4Nb-3Mn Alloy

2012 ◽  
Vol 706-709 ◽  
pp. 1100-1105
Author(s):  
Trevor Sawatzky ◽  
Dong Yi Seo ◽  
H. Saari ◽  
D. Laurin ◽  
Young Won Kim
Keyword(s):  
Heat Treatment ◽  
Titanium Aluminide ◽  
Hot Isostatic Pressing ◽  
Lamellar Microstructure ◽  
Beta Phase ◽  
Heat Treatment Condition ◽  
Tensile Creep ◽  
Nominal Composition ◽  
Gamma Titanium Aluminide ◽  
Heat Treated

Pre-alloyed beta gamma titanium aluminide powder with a nominal composition of TiAl-4Nb-3Mn is consolidated by hot isostatic pressing. After consolidation, a step cooled heat treatmentis performed to homogenize the material and produce a fully lamellar microstructure. Various agingheat treatments are then performed with the goal of forming interfacial beta phase precipitates alonglamellar interfaces. The step cooled heat treatment produces a relatively fine microstructure with alamellar spacing of 0.04 μm and an average lamellar colony size of 60 μm. The aging heat treatmentsgenerate beta phase precipitates along lamellar colony boundaries but not along lamellar interfaces,and result in lamellar degredation and grain growth. Constant load tensile creep and room temperaturehardness tests are performed on step cooled heat treated and step cooled heat treated and aged specimens.Creep resistance, generally, improves with aging time, even with no interfacial precipitation,and the lamellar degredation that occurs with aging. The microstructures of the as-tested specimensare characterized and related to the creep properties. The hardness values are also compared as afunction of selected heat treatment condition and microstructural features.

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