The Role of Frictional Sliding in Transverse Failure of a Titanium Aluminide Composite

2009 ◽  
pp. 58-58-8
Author(s):  
DB Marshall ◽  
WL Morris ◽  
BN Cox ◽  
DA Kouris
Keyword(s):  
Titanium Aluminide ◽  
Frictional Sliding ◽  
Transverse Failure

scholarly journals Detachment of compliant films adhered to stiff substrates via van der Waals interactions: role of frictional sliding during peeling

2014 ◽  
Vol 11 (97) ◽  
pp. 20140453 ◽  
Author(s):  
Rachel R. Collino ◽  
Noah R. Philips ◽  
Michael N. Rossol ◽  
Robert M. McMeeking ◽  
Matthew R. Begley
Keyword(s):  
Van Der Waals ◽  
Van Der Waals Interactions ◽  
Work Of Adhesion ◽  
Interface Fracture ◽  
Strong Function ◽  
Frictional Sliding ◽  
Fracture Models ◽  
Synthetic Adhesives ◽  
Interface Sliding

The remarkable ability of some plants and animals to cling strongly to substrates despite relatively weak interfacial bonds has important implications for the development of synthetic adhesives. Here, we examine the origins of large detachment forces using a thin elastomer tape adhered to a glass slide via van der Waals interactions, which serves as a model system for geckos, mussels and ivy. The forces required for peeling of the tape are shown to be a strong function of the angle of peeling, which is a consequence of frictional sliding at the edge of attachment that serves to dissipate energy that would otherwise drive detachment. Experiments and theory demonstrate that proper accounting for frictional sliding leads to an inferred work of adhesion of only approximately 0.5 J m −2 (defined for purely normal separations) for all load orientations. This starkly contrasts with the interface energies inferred using conventional interface fracture models that assume pure sticking behaviour, which are considerably larger and shown to depend not only on the mode-mixity, but also on the magnitude of the mode-I stress intensity factor. The implications for developing frameworks to predict detachment forces in the presence of interface sliding are briefly discussed.

Glasses and Multi-Component Sol-Gels for Use as High-Temperature Protective Coatings

1990 ◽  
Vol 180 ◽  
Author(s):  
Lauri J. Devore ◽  
Nora R. Osborne
Keyword(s):  
Thin Film ◽  
High Temperature ◽  
Ambient Temperature ◽  
Titanium Aluminide ◽  
Protective Coatings ◽  
Sol Gel ◽  
Film Coatings ◽  
Interfacial Conditions ◽  
Thin Film Coatings

ABSTRACTTwo multi-component sol-gel compositions were developed and compared to several commercially available high-temperature glasses. All were then used and characterized as protective coatings for intermetallic titanium aluminide.The sol-gels were studied as thin film coatings and the commercial glasses were studied as enameled coatings. Attention was given to (1) the effect of the application temperature on the original microstructure of the metal, and (2) the role of interfacial conditions between the glass and metal in cyclic and isothermal thermal cycles between ambient temperature and 760°C (1400°F).

Hot Working of Ti Aluminide Made through Reaction Synthesis

2012 ◽  
Vol 710 ◽  
pp. 137-142
Author(s):  
Rohit Kumar Gupta ◽  
Bhanu Pant ◽  
Vijaya Agarwala ◽  
Parameshwar Prasad Sinha
Keyword(s):  
Microstructure Evolution ◽  
Titanium Aluminide ◽  
Hot Isostatic Pressing ◽  
Hot Working ◽  
Reaction Synthesis ◽  
Refined Grains ◽  
Isostatic Pressing ◽  
Die Forging ◽  
Open Die Forging

Hot working of titanium aluminide made through reaction synthesis (RS) has been studied. Hot isostatic pressing under argon, isothermal pressing under vacuum, open die forging and pack forging was carried out. Hot worked billet samples were characterized for density and microstructure evolution. Presence of refined grains and dynamically recrystallized grains were observed. In case of open die forging, presence of twins was also found. From the present study, near isothermal working through near conventional processes has been confirmed. However, role of isothermal working in obtaining crack free sound deformed product has also been noted.

On the role of frictional sliding in the compressive fracture of ice and granite: Terminal vs. post-terminal failure

2006 ◽  
Vol 54 (15) ◽  
pp. 3923-3932 ◽  
Author(s):  
E SCHULSON ◽  
A FORTT ◽  
D ILIESCU ◽  
C RENSHAW
Keyword(s):  
Frictional Sliding ◽  
Compressive Fracture

Effect of fiber coating on the mechanical behavior of SiC fiber-reinforced titanium aluminide composites

1993 ◽  
Vol 8 (4) ◽  
pp. 905-916 ◽  
Author(s):  
S.M. Jeng ◽  
J-M. Yang ◽  
J.A. Graves
Keyword(s):  
Mechanical Behavior ◽  
Titanium Aluminide ◽  
Effective Diffusion ◽  
Fiber Surface ◽  
Model Material ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Fiber Coating ◽  
Sic Fiber

The effects of fiber surface coatings on the mechanical behavior and damage mechanisms of SCS-6 fiber-reinforced titanium aluminide matrix composites have been studied. Two different coating layers are used as model material: a brittle TiB2 and a ductile Ag/Ta duplex layer. The role of the coating layer on the interfacial reaction, interfacial properties, and mechanical behavior of the composites was characterized. Results indicate that both TiB2 and Ag/Ta are effective diffusion barriers in preventing fiber/matrix interfacial reactions during composite consolidation. However, the deformation mechanisms and crack propagation characteristics in these two coated composites are quite different. The criteria for selecting an improved interlayer to tailor a strong and tough fiber-reinforced titanium aluminide matrix composite are also discussed.

Oxidation Behavior of Intermetallic Titanium Aluminide Alloys

2012 ◽  
Vol 1516 ◽  
pp. 77-88 ◽  
Author(s):  
Michael Schütze ◽  
Simone Friedle
Keyword(s):  
Oxide Scale ◽  
Titanium Aluminide ◽  
Titanium Aluminides ◽  
Life Time ◽  
Alloying Elements ◽  
Protective Oxide ◽  
High Temperature Alloys ◽  
Titanium Aluminide Alloys ◽  
Slow Growing

ABSTRACTAbove 750-800°C oxidation becomes a serious life time issue for the new group of intermetallic light-weight high temperature alloys based on titanium aluminides (TiAl). Fast growing titanium oxide competes with protective alumina as a surface scale in the oxidation reaction by which the formation of a slow-growing protective oxide scale is prevented. The key to the development of alloys with sufficient oxidation resistance is the understanding of the thermodynamic and kinetic situation during the oxidation process. The latter is influenced by the type of alloying elements, the Al- and Ti-activities in the alloy, the oxidation temperature and the environment (e.g. dry or humid air, etc.). This paper provides a comprehensive summary of the oxidation mechanisms and the parameters influencing oxide scale formation. Besides the role of metallic alloying elements, the halogen effect will also be discussed. The paper finishes with recent results concerning the prevention of oxidation-induced room temperature embrittlement of TiAl alloys.

Effect of Ti Particle Size on Reaction Synthesis of Ti Aluminide

2012 ◽  
Vol 710 ◽  
pp. 314-319 ◽  
Author(s):  
Rohit Kumar Gupta ◽  
Bhanu Pant ◽  
Vijaya Agarwala ◽  
Parameshwar Prasad Sinha
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Titanium Aluminide ◽  
Reaction Synthesis ◽  
Particle Sizes ◽  
Minor Phase ◽  
Chemical Homogeneity ◽  
Major Phase ◽  
Ti Powder

Titanium aluminide intermetallic was made through reaction synthesis (RS) process using elemental powders. Pressure assisted synthesis was carried out at high temperature under vacuum. Ti powder with two different particle sizes (200μm and 30μm average) were used in RS. Synthesized blocks were homogenized and characterized for chemical homogeneity, density, phase formation and microstructure evolution. Products near to theoretical density have been obtained with uniform chemistry after homogenization. Al3Ti as a major phase along with TiAl as minor phase was confirmed after RS and TiAl along with Ti3Al was observed after homogenization. Homogenization cycle was found to be different for the alloys made through different Ti particle sizes. Significant role of Ti particle size has been observed in this pressure assisted RS process.

On the Role of Interphases in the Transverse Failure of Fiber Composites

1994 ◽  
Vol 3 (4) ◽  
pp. 357-377 ◽  
Author(s):  
M. Gosz ◽  
B. Moran ◽  
J.D. Achenbach
Keyword(s):  
Fiber Composites ◽  
Transverse Failure
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