Ti alloys

Oxygen Acetaldehyde, acetone, alcohols, alkali metals, alkaline earth metals, Al-Ti alloys, ether, carbon disulflde, halocarbons, hydrocarbons, metal hydrides, 1,3,5-trioxane... 

The SME was first reported in 1951 involving a Au—Cd alloy (1). Many other alloys exhibiting this behavior have since been discovered some of these are Hsted in Table 1. It was, however, the discovery of the SME in the nominally equiatomic Ni—Ti alloy that led to commercial appHcations. This... 

Casting of Ti alloys for crowns and bridges is done in investment molds that have been allowed to cool almost to room temperatures after firing. The castings are cleaned in electrolytic solutions or in special chemical polishing solutions that impart a bright smooth surface finish to the casting... 

In some materials and environments, cracks grow steadily under a constant stress intensity K which is much less than (Fig. 23.8). This is obviously dangerous a structure which is safe when built can become unsafe with time. Examples are brass in ammonia, mild steel in caustic soda, and some A1 and Ti alloys in salt water. 

III Ti, Ti alloys Halide-free acids >0.0 >-0.32 Protection against weight loss... 

R. Yang, S.V. Parker, J.A. Leake, R.W. Cahn, New metastable phases in nickel -rich Ni-Al-Ti alloys, in Alloy Modelling and Design, ed.G.M.Stocks and P.A. Turchi, The Minerals, Metals Materials Society (1994), p.303. 

In addition to the alloys in Table 4.21, Ni-Sn and Ni-Ti alloys also possess useful corrosion resistance. Ni-Sn alloys are extremely brittle and, because of this, are used only as electrodeposited coatings. Ni-Ti alloys over a wide range of compositions have been studied, of which perhaps the intermetallic compound NiTi (55 06Ni-44-94Ti) has attracted the most interest. 

Fig. 4.31 Anodic behaviour of Ni-Ti alloys in HCl + 3 -5% NaCKpFl 1), de-aerated with argon, at 22-2°C the potential was increased by 0-02 V every minute (after Sedriks, el al )...

Intergranular corrosion Carbon steels in NO solns Some Al alloys in Cl Cu-Zn alloys solns, high in NH7 solns potentials Fe-Cr-Ni steels in Cl solns Cu-Zn alloys Mg-A alloys in NO in CrO + solns Cl solns Ti alloys in High methanol. A strength alloys, low steels in Cl potentials solns Brittle fracture... 

Centrifugal Shot Casting Atomization (CSC) 150-1000 Standard deviation 1.3-1.4 Fe, Co, Ni, Ti alloys, Alumina, Uranium monocarbide 102-105 Narrow size distribution Coarse particles, Low EE... 

The EBRD process has been demonstrated applicable to the atomization of a variety of reactive and refractory metals and alloys in addition to Ti alloys. The process is being further developed to utilize highly contaminated raw materials and to produce high quality powders for hot isostatic pressing application without additional treatment. 

According to their effects on Ti alloying, elements may be subdivided in the following categories which represent an example not only of a structural, but also of an application-oriented classification ... 

Main uses of the metal. It is especially used as an alloying element in the steel industry and in the preparation of non-ferrous alloys (V-Ti alloys, Ni-based superalloys, etc.). 

Characteristics and implementation of the treatments depend on the expected results and on the properties of the material considered a variety of processes are employed. In ferrous alloys, in steels, a eutectoid transformation plays a prominent role, and aspects described by time-temperature-transformation diagrams and martensite formation are of relevant interest. See a short presentation of these points in 5.10.4.5. Titanium alloys are an example of the formation of structures in which two phases may be present in comparable quantities. A few remarks about a and (3 Ti alloys and the relevant heat treatments have been made in 5.6.4.1.1. More generally, for the various metals, the existence of different crystal forms, their transformation temperatures, and the extension of solid-solution ranges with other metals are preliminary points in the definition of convenient heat treatments and of their effects. In the evaluation and planning of the treatments, due consideration must be given to the heating and/or cooling rate and to the diffusion processes (in pure metals and in alloys). 

The friction of this Ti alloy was remarkably steady over a range of rotation speeds up to 5500 rpm, increasing somewhat at the lower speeds, and for a range of loads, from 4 to 18 N at a constant sliding speed. The measured surface roughness of the worn surfaces was 2.1 pm Sa, where Sa is the surface arithmetic roughness. 

Additional surface modifications on vapor deposited SiC fibers, including WC. TaC, TiN, B4C, Al, Ni and Fe, have been applied with varying degree of success (Wawner and Nutt, 1980 DeBolt, 1982 Wawner, 1988). After exhaustive trial and error, TiB is selected as an additional coating material to further prevent the diffusion-induced reactions between the SCS-6 fibers and matrix materials, including Ti alloys and Ti Al intermetallic alloys (e.g. Ti Al, TiAl and TiAl ) (Donncllan and Frazier, 1991 James et al., 1991). When the coated fiber is subjected to tensile... 

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