Titanium containing alloys

The question of the compatibility of metals and alloys with carbon and carbonaceous gases has assumed considerable importance in connection with the development of the gas-cooled nuclear reactor in which graphite is used as a moderator and a constituent of the fuel element, and carbon dioxide as the coolant. Tests of up to 1 000 h on a series of metals and nickel-containing alloys under pressure contact with graphite at 1 010°C" showed that only copper was more resistant than nickel to diffusion of carbon and that the high-nickel alloys were superior to those of lower nickel content. The more complex nickel-chromium alloys containing titanium, niobium and aluminium were better than the basic nickel-chromium materials. 

By far the most important use of titanium is in making alloys. The metal is most commonly added to steel. It adds strength to the steel and makes it more resistant to corrosion (rusting). Titanium also has another advantage in alloys. Its density is less than half that of steel. So a steel alloy containing titanium weighs less, pound-for-pound, than does the pure steel alloy. 

Stabilizing is done on certain corrosion resistant stainless steels and nickel alloys containing titanium, niobium or tantalum to enhance corrosion resistance. They are heated to specific temperatures so that these elements combine preferentially with carbon, preventing any detrimental loss of... 

X 10 M solution of the vanadium complex exhibits absorbances of 0.400 and 0.600 at 415 and 455 nm, respectively. A 1.000-g sample of an alloy containing titanium and vanadium was dissolved, treated with excess hydrogen peroxide, and diluted to a final volume of 100 mL. The absorbance of the solution was 0.685 at 415 nm and 0.513 at 455 nm. What were the percentages of titanium and vanadium in the alloy ... 

Alloy 270 is a high-purity, low-inclusion version of alloy 200. Alloy 301 (also referred to by tradename Duranickel) is a precipitation-hardenable alloy containing aluminum and titanium. Alloy 300 (also called by the tradename Permanickel) is a moderately precipitation-hardenable alloy containing titanium and magnesium that also possesses higher thermal and electrical conductivity. 

The first iron—nickel martensitic alloys contained ca 0.01% carbon, 20 or 25% nickel, and 1.5—2.5% aluminum and titanium. Later an 18% nickel steel containing cobalt, molybdenum, and titanium was developed, and still more recentiy a senes of 12% nickel steels containing chromium and molybdenum came on the market. 

The property most frequently cited in connection with the use of Ti dental or medical appHances is titanium s unique biocompatibiHty. This helps practitioners avoid occasional allergic reactions that occur with nickel or chromium alloys, and removes concerns about the toxic or carcinogenic potential of appHances that contain nickel, chromium, or beryUium. Wrought alloys of titanium are used for orthodontic wires because of their unique elastic... 

Samples were tested on in a melt of salts (75% Na SO, 25% NaCl) at 950°C in an air atmosphere for 24 hours. Micro X-rays spectrum by the analysis found that the chemical composition of carbides of an alloy of the ZMI-3C and test alloys differs noticeably. In the monocarbide of phase composition of an alloy of the ZMI-3C there increased concentration of titanium and tungsten is observed in comparison with test alloys containing chemical composition tantalum. The concentration of more than 2% of tantalum in test alloys has allowed mostly to deduce tungsten from a mono carbide phase (MC) into solid solution. Thus resistance of test alloys LCD has been increased essentially, as carbide phase is mostly sensitive aggressive environments influence. The critical value of total molybdenum and tungsten concentration in MC should not exceed 15%. 

Many shell-and-tube condensers use copper alloy tubes, such as admiralty brasses (those containing small concentrations of arsenic, phosphorus, or antimony are called inhibited grades), aluminum brasses, and cupronickel austenitic stainless steel and titanium are also often used. Utility surface condensers have used and continue to use these alloys routinely. Titanium is gaining wider acceptance for use in sea water and severe service environments but often is rejected based on perceived economic disadvantages. 

Griess has observed crevice corrosion of titanium in hot concentrated solutions of Cl , SOj I ions, and considers that the formation of acid within the crevice is the major factor in the mechanism. He points out that at room temperature Ti(OH)3 precipitates at pH 3, and Ti(OH)4 at pH 0-7, and that at elevated temperatures and at the high concentrations of Cl ions that prevail within a crevice the activity of hydrogen ions could be even greater than that indicated by the equilibrium pH values at ambient temperatures. Alloys that remain passive in acid solutions of the same pH as that developed within a crevice should be more immune to crevice attack than pure titanium, and this appears to be the case with alloys containing 0-2% Pd, 2% Mo or 2[Pg.169]

The corrosion behaviour of amorphous alloys has received particular attention since the extraordinarily high corrosion resistance of amorphous iron-chromium-metalloid alloys was reported. The majority of amorphous ferrous alloys contain large amounts of metalloids. The corrosion rate of amorphous iron-metalloid alloys decreases with the addition of most second metallic elements such as titanium, zirconium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, nickel, copper, ruthenium, rhodium, palladium, iridium and platinum . The addition of chromium is particularly effective. For instance amorphous Fe-8Cr-13P-7C alloy passivates spontaneously even in 2 N HCl at ambient temperature ". (The number denoting the concentration of an alloy element in the amorphous alloy formulae is the atomic percent unless otherwise stated.)... 

Alloys containing up to l o copper and about 0 - l o titanium have been used in strip form for roofing on a large scale in France, Germany, the UK and elsewhere since about 1960, but no details are available on how their corrosion resistance compares with that of the traditional unalloyed rolled zinc. Initially they are lighter in colour and they remain bright a little longer. 

Niobium-Zirconium-Titanium Niobium alloys containing zirconium and titanium have improved resistance to high-temperature water and have been evaluated for use in pressurised-water nuclear reactors. 

The stress-corrosion cracking hazard for titanium alloys containing aluminium is significantly higher than that obtaining for commercially pure titanium, and in addition to stress-corrosion cracking in methanol and red... 

It should be noted that swarf from a zirconium-titanium alloy containing approximately 50% by weight of each element is prone to pyrophoricity in air. It has also been reported that when zirconium is welded to titanium, the welded zone is much more sensitive to corrosion than either of the parent metals. If, therefore, it is proposed to use my construction in which zirconium is welded to titanium, caution should be observed in the machining of welds, and the corrosion behaviour of the weld should be checked by prior testing in the environment with which the construction will be employed. 

Tantalum-Titanium Bishop examined the corrosion resistance of this alloy system in hydrochloric, sulphuric, phosphoric and oxalic acids and found that alloys containing up to about 50% titanium retained much of the superlative corrosion resistance of tantalum. Under more severe conditions, a titanium content of below 30% appears advisable from the standpoint of both corrosion resistance and hydrogen embrittlement, although contacting or alloying the material with noble metals greatly decreases the latter type of attack. Tantalum-titanium alloys cost less than tantalum because titanium is much cheaper than tantalum, and because the alloys are appreciably lower in density. These alloys are amenable to hot and cold work and appear to have sufficient ductility to allow fabrication. 

The addition of beryllium and silicon to nickel-palladium alloys gives very good high-temperature brazes, especially for alloys containing aluminium and titanium. 

Of the weldability problems, nickel and nickel-based alloys are particularly prone to solidification porosity, especially if nitrogen is present in the arc atmosphere, but this may be controlled by ensuring the presence of titanium as a denitrider in the filler and maintaining, a short arc length. The other problem that may be encountered is hot cracking, particularly in alloys containing Cr, Si, Ti, Al, B, Zr, S, Pb and P. 

Ferro-alloys Master alloys containing a significant amount of bon and a few elements more or less soluble in molten bon which improve properties of bon and steels. As additives they give bon and steel better characteristics (increased tensile sbength, wear resistance, corrosion resistance, etc.). For master alloy production carbothermic processes are used for large-scale ferro-sihcon, ferro-chromium, ferro-tungsten, ferro-manganese, ferro-nickel and metallothermic processes (mainly alumino and sihco-thermic) for ferro-titanium, ferro-vanadium, ferro-molybdenum, ferro-boron. 

An alloy of titanium containing 40—50% Ti and 45—50% Si is used as an additive in cast iron to shorten the graphite flakes. The effect is to provide a smooth casting surface. The resulting casting is then used to produce glass botde molds. 

Titanium alloys suffer crevice corrosion in hot aqueous chloride media, but the alloy containing molybdenum, 3A1-8V-6 Cr-4Zr-4 Mo has good resistance to crevice corrosion and is successfully used in hot sour well and geothermal brine... 

Although some of the metals in the second and third transition series are certainly important, the first-row metals constitute the extremely significant and useful structural metals. In addition to the metals themselves, an enormous number of alloys containing these metals are widely used, as are many compounds of the metals. Of all the compounds of the transition metals, titanium dioxide, Ti02, is produced in the largest quantity (approximately 2 billion lb/year) because of its extensive use in paints. 

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