Effect of niobium additions on CO2-enhanced oxidation of titanium-aluminum intermetallic alloys

1997 ◽  
Vol 48 (3-4) ◽  
pp. 201-214 ◽  
Author(s):  
Jeffrey W. Fergus
Author(s):  
O. Popoola ◽  
A.H. Heuer ◽  
P. Pirouz

The addition of fibres or particles (TiB2, SiC etc.) into TiAl intermetallic alloys could increase their toughness without compromising their good high temperature mechanical and chemical properties. This paper briefly discribes the microstructure developed by a TiAl/TiB2 composite material fabricated with the XD™ process and forged at 960°C.The specimens for transmission electron microscopy (TEM) were prepared in the usual way (i.e. diamond polishing and argon ion beam thinning) and examined on a JEOL 4000EX for microstucture and on a Philips 400T equipped with a SiLi detector for microanalyses.The matrix was predominantly γ (TiAl with L10 structure) and α2(TisAl with DO 19 structure) phases with various morphologies shown in figure 1.


Author(s):  
Ian M. Anderson

B2-ordered iron aluminide intermetallic alloys exhibit a combination of attractive properties such as low density and good corrosion resistance. However, the practical applications of these alloys are limited by their poor fracture toughness and low room temperature ductility. One current strategy for overcoming these undesirable properties is to attempt to modify the basic chemistry of the materials with alloying additions. These changes in the chemistry of the material cannot be fully understood without a knowledge of the site-distribution of the alloying elements. In this paper, the site-distributions of a series of 3d-transition metal alloying additions in B2-ordered iron aluminides are studied with ALCHEMI.A series of seven alloys of stoichiometry Fe50AL45Me5, with Me = {Ti, V, Cr, Mn, Co, Ni, Cu}, were prepared with identical heating cycles. Microalloying additions of 0.2% B and 0.1% Zr were also incorporated to strengthen the grain boundaries, but these alloying additions have little influence on the matrix chemistry and are incidental to this study.


Alloy Digest ◽  
1997 ◽  
Vol 46 (9) ◽  

Abstract Sandvik Ti-3Al-2.5V Grade 9 titanium-aluminum alloy offers excellent corrosion resistance, especially to chloride media, and has a high strength-to-weight ratio, which is especially suitable for use in aerospace applications. Tubing can be produced having a CSR (contractile strain ratio) that enhances the fatigue endurance limit. This datasheet provides information on composition, physical properties, elasticity, tensile properties, and bend strength as well as fatigue. It also includes information on corrosion resistance as well as forming, machining, and joining. Filing Code: TI-109. Producer or source: Sandvik.


2020 ◽  
pp. 313-317
Author(s):  
A.I. Kovtunov ◽  
Yu.Yu. Khokhlov ◽  
S.V. Myamin

Titanium—aluminum, titanium—foam aluminum composites and bimetals obtained by liquid-phase methods, are increasingly used in industry. At the liquid-phase methods as result of the reaction diffusion of titanium and aluminum is formed transitional intermetallic layer at the phase boundary of the composite, which reduces the mechanical properties of titanium and composite. To reduce the growth rate of the intermetallic layer between the layers of the composite and increase its mechanical properties, it is proposed to alloy aluminum melt with nickel. The studies of the interaction of titanium and molten aluminum alloyed with nickel made it possible to establish the effect of temperature and aluminizing time on the thickness, chemical and phase compositions of the transition intermetallic layer. The tests showed the effect of the temperature of the aluminum melt, the nickel concentration on the strength properties of titanium—aluminum bimetal.


2019 ◽  
Author(s):  
Jiahui Ji ◽  
Rashed M. Aleisa ◽  
Huan Duan ◽  
Jinlong Zhang ◽  
Yadong Yin ◽  
...  

1985 ◽  
Vol 50 (10) ◽  
pp. 2093-2100
Author(s):  
Štěpán Pick ◽  
Mojmír Tomášek ◽  
Mojmír Šob

Partial wave analysis together with the qualitative examination of hybridization has been performed for two ordered intermetallic alloys with CsCl structure, FeV, and CoTi. The results resemble those obtained previously for FeTi, although important deviations are present as well. The stabilization of the ordered phase is again due to ionic effects. Qualitative arguments are suggested to explain the small stability of the CsCl phase of FeV and some differences in the FeTi and CoTi phase diagrams.


2019 ◽  
Vol 28 (3) ◽  
pp. 433-443 ◽  
Author(s):  
Mingwen Bai ◽  
Bo Song ◽  
Liam Reddy ◽  
Tanvir Hussain

Abstract MCrAlY–Al2O3 composite coatings were prepared by high-velocity oxygen fuel thermal spraying with bespoke composite powder feedstock for high-temperature applications. Powder processing via a suspension route was employed to achieve a fine dispersion of α-Al2O3 submicron particles on the MCrAlY powder surface. This was, however, compromised by ~ 50% less flowability of the feedstock during spraying. Nevertheless, the novel powder manufacturing process introduced in this study has shown potential as an alternative route to prepare tailored composite powder feedstock for the production of metal matrix composites. In addition, the newly developed MCrAlY–Al2O3 composite coatings exhibited superior oxidation resistance, compared to conventional MCrAlY coatings, with the formation of nearly exclusively Al2O3 scale after isothermal oxidation at 900 °C for 10 h. The addition of α-Al2O3 particles in the MCrAlY coatings as a second phase was found to have promoted the formation of YAG oxides (YxAlyOz) during spraying and also accelerated the outwards diffusion of Al, which resulted in enhanced oxidation resistance.


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