Titanium and its alloys

Titanium is a metal that has become available for special engineering applications relatively recently. It is an element in the IVB column of the periodic table. Titanium is abundant in nature as the oxide, but this oxide is relatively difficult to purify. One of the most popular ways of refining 

Titanium is separated from the chloride by leaching with water, and then vacuum melting and allo5dng. One of the most widely used alloys is 6 wt % aluminum, 4 wt % vanadium, and the remainder titanium (Ti-6-4). The chief characteristics of titanium are  

Titanium alloys are used for mechanical parts in the aircraft and space industries due to their high strength-to-weight ratio. Titanium is difficult to machine due to its low thermal properties, and its tendency to form strong bonds with metal oxides. 

The commercial importance of this metal was first recognized in 1950s when its high strength/density ratios were found attractive in aerospace applications. The corrosion resistance in a variety of conditions led to its use in wet chlorine gas coolers for chlor-alkali cells, chlorine and chlorine dioxide bleaching equipment in pulp/paper mills, and reactor interiors for pressure acid leaching of metallic ores. The metal and its alloys were used in seawater power plant condensers, with over 400 million feet installed in application.65,66 The most commonly used alloys and their composition are given in Table 4.48. 

Common alloy ASTM Nominal tensile yield 

Group II Low-alloy-content titanium with Pd/Ru additions  

Features of the different groups of titanium alloys are as follows  

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Titanium and titanium alloy s. The possibility of deterioration of titanium and its alloys above 315°C (600°F). 

Metals and alloys Iron and steels Aluminium and its alloys Copper and its alloys Nickel and its alloys Titanium and its alloys... 

This induced an increasing number of papers devoted to the study of the hydrogen effect on the mechanical properties of titanium alloys -lo SQjjjg interesting effects of hydrogen in titanium and its alloys are discussed below on the basis of the experimental data obtained at ISSP RAS (the early experiments were carried out in co-operation with the Institute of Metal Physics UD RAS). 

A rapidly growing use in the medical field is for surgical implants as either bone plates and screws, joint replacements, or for the repair of cranial injuries. Here, titanium and its alloys have the advantages of complete compatibility with body fluids, low density, and low modulus. Applications also exist in dentistry. 

Titanium alloys generally show a combination of strength and biocompatibility which makes them suitable for medical devices (prosthesis, surgical instruments). The high strength Ti-6Al-7Nb alloy has several orthodontic applications. Only a limited number of alloys have the necessary combinations of properties needed for successful use in the human body. Titanium and its alloys, stainless steels and cobalt-chromium alloys are the workhorse alloys in the medical device industry. 

Titanium and its alloys are said to be less susceptible to mineral scaling in sea water than most other metals. (The corrosion products on a metal, such as steel, prob-... 

The hexagonal close-packed (hep) metals exhibit mechanical properties intermediate between those of the fee and bcc metals. For example, zinc suffers a ductile-to-brittle transition, whereas zirconium and pure titanium do not. The latter and its alloys have an hep structure, remain reasonably ductile at low temperatures, and have been used for many applications where weight reduction and reduced heat leakage through the material have been important. However, small impurities of oxygen, nitrogen, hydrogen, and carbon can have a detrimental effect on the low-temperature ductility properties of titanium and its alloys. 

Sheet, thin plate, welded tubing, and small-diameter bar of commercially pure titanium are manufactured into parts by conventional cold-working techniques. The formability of titanium, when worked at room temperature, is like that of cold-rolled stainless steel. At 65°C the formability compares with stainless steel annealed at room temperature. Cold-working maybe difficult for some titanium alloys and heat may be required, especially for severe forming operations. Generally, titanium and its alloys are worked between 200 and 300°C. Lubricants reduce friction and galling. Slow forming speeds at controlled rates improve workability and are recommended for more difficult operations. 

Keith, R. E., Adhesive Bonding of Titanium and Its Alloys, Handbook of Adhesives Bonding, C. V. Cagel, ed., McGraw-Hill, New York, 1973. 

Materials such as metals, alloys, steels and plastics form the theme of the fourth chapter. The behavior and use of cast irons, low alloy carbon steels and their application in atmospheric corrosion, fresh waters, seawater and soils are presented. This is followed by a discussion of stainless steels, martensitic steels and duplex steels and their behavior in various media. Aluminum and its alloys and their corrosion behavior in acids, fresh water, seawater, outdoor atmospheres and soils, copper and its alloys and their corrosion resistance in various media, nickel and its alloys and their corrosion behavior in various industrial environments, titanium and its alloys and their performance in various chemical environments, cobalt alloys and their applications, corrosion behavior of lead and its alloys, magnesium and its alloys together with their corrosion behavior, zinc and its alloys, along with their corrosion behavior, zirconium, its alloys and their corrosion behavior, tin and tin plate with their applications in atmospheric corrosion are discussed. The final part of the chapter concerns refractories and ceramics and polymeric materials and their application in various corrosive media. 

Titanium is used in medicine mainly for its mechanical benefits in surgical and dental materials in a host of orthopedic and orthodontic appliances, with or without other metals (for example nickel, cobalt, chromium), and generally without serious adverse effects. Titanium and its alloys are in use as implants in bone surgery (1,2) and in dental materials (3,4). Research on the biocompatibility of metal and tissue continues (5). 

Metallic titanium and its alloys (especially those with aluminum and vanadium) combine the advantages of high strength and light weight and are therefore used widely in the aerospace industry for the bodies and engines of airplanes. The major natural source for titanium is the ore rutile, which contains titanium dioxide... 

The dithizone method has been applied for determining copper in biological materials [12,16], water [94], tin [3], titanium and its alloys [95]. Copper has been determined in sea sediments (in the presence of Hg and Pb) by derivative spectrophotometry [96]. 

The stated considerations are correct for titanium. In titanium alloys evolution of lamellar microstructure (typical for titanium alloys) takes place due to development of globularization [8], The process develops by means of substructure formation in the lamellas of phases, division of lamellas and transformation of lamellas parts into globular particles. Keep the process its main features in the case of SMC structure formation There are no such investigations in the scientific literature. The relative simplicity of the method and its commercial application bring up a question to investigate the features of microstructure evolution and mechanical behavior of titanium and its alloys during successive deformation/rotation of samples as well as scale up process capability for production of SMC structure in large-scale billets and sheets. 

Iron does not passivate in most environments and, therefore, performs best when the oxidizing power of the environment is as low as possible, for example, by deaeration as mentioned above. In contrast, a large class of industrially important alloys depend upon sufficiently oxidizing conditions to produce a protective passive film if they are to perform satisfactorily. These alloys include stainless steels, nickel-base alloys, titanium and its alloys, and many others. 

Bioinert materials are materials that display minimal, if any, interaction with surrounding tissues examples of these are titanium and its alloys, alumina, partially stabilised zirconia, carbon and possibly ultrahigh molecular weight polyethylene (UHMWPE). In the case of bioinert materials bone remodelling occurs by a shape-mediated contact osteogenesis. 

Application of plasma electrolytic oxidation to bioactive surface formation on titanium and its alloys. RSC Adv., 3, 19725-19743. 

In industrial applications the environments usually contain more than one reactant. For example high temperature oxidation occurs in air by the combined attack of oxygen, nitrogen and quite frequently water vapour. However, most of the studies concerning the oxidation resistance are performed in dry oxygen or dry air. The oxidation behaviour of the intermetallic phases of theTi-Al system has recently received considerable attention. The influence of water vapour on the oxidation of titanium aluminides has not been studied intensively. There are only a few studies of the high temperature corrosion of titanium and its alloys. 

Thus the reaction of sodium chloride with titanium from the alloy, or rutile from the scale leads to the formation of TiCl2, Na2Ti03, HC1 and Cl2.This list of reactions is by no means exhaustive, and may also involve reaction with other alloying additions which may be substituted for the titanium metal. Particularly, the role of aluminium must be of importance. A thermodynamic analysis by Travkin et al. [32] confirms that complex oxide scales are formed when titanium and its alloys react with NaCl. Particularly that the formation of volatile metallic chlorides are thermodynamically favourable, especially for alloying additions Zr, Mo and Al. The subsequent pyrohydrolysis of these metal chlorides results in the formation of HC1 gas, particularly with Mod., and AlClj. Furthermore, such pyrohydrolysis of halide salts may be accelerated by the presence of alumina within the scales, which acts as a catalyst [25]. 

During several decades, stainless steel was the most frequently used alloy for joint replacements. At present. Co-base alloys have taken first place, and about 70% of all orthopedic implants are made from Co-Cr alloys. During the past 20 years, titanium and its alloys have become more important due to their bone-like elasticity and their excellent biological behavior. 

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