Rapid titanium alloys

This process, originally designated as RSR (rapid solidification rate), was developed by Pratt and Whitney Aircraft Group and first operated in the late 1975 for the production of rapidly solidified nickel-base superalloy powders.[185][186] The major objective of the process is to achieve extremely high cooling rates in the atomized droplets via convective cooling in helium gas jets (dynamic helium quenching effects). Over the past decade, this technique has also been applied to the production of specialty aluminum alloy, steel, copper alloy, beryllium alloy, molybdenum, titanium alloy and sili-cide powders. The reactive metals (molybdenum and titanium) and... 

Powder Formation. Metallic powders can be formed by any number of techniques, including the reduction of corresponding oxides and salts, the thermal dissociation of metal compounds, electrolysis, atomization, gas-phase synthesis or decomposition, or mechanical attrition. The atomization method is the one most commonly used, because it can produce powders from alloys as well as from pure metals. In the atomization process, a molten metal is forced through an orifice and the stream is broken up with a jet of water or gas. The molten metal forms droplets to minimize the surface area, which solidify very rapidly. Currently, iron-nickel-molybdenum alloys, stainless steels, tool steels, nickel alloys, titanium alloys, and aluminum alloys, as well as many pure metals, are manufactured by atomization processes. 

Hydrogen transport in a metal can occur by lattice diffusion, dislocation motion, or short-circuit diffusion along grain boundaries. Hydrogen can diffuse rapidly through the lattice in many metals, particularly those with a body-centered cubic (bcc) structure such as a-iron, ferritic steels, and )3-titanium alloys. However, grain boundary diffusion and dislocation... 

Rapid-Solidification Processing of Precipitate- and Dispersion-Strengthened Titanium Alloys... 

Col78 ] Collings, E.W, Mobley, C.E., Maringer, R.E., and Gegel, H.L., Selected Properties of Melt-Extracted Titanium-Base PolycrystaUine Alloys, in Rapidly Quenched Alloys III, B. Cantor, Ed., Vol 1, The Metals Society (UK), 1978, p. 188-191... 

Eyl86] Eylon, D., Cooke, C.M., and Froes, F.H., Production of Metal Matrix Composites from Rapidly Solidified Titanium Alloy Foils, in Titanium Rapid Solidification Tkchnology, F.H. Froes and D. Eylon, Ed., The Metallurgical Society, 1986, p. 311-322... 

Fro86] Froes, F.H. and Rowe, R.G., Rapidly SoHdified Titanium, in Rapidly Solidified Alloys and Their Mechanical and Magnetic Properties, B.C. Giessen, DJE. PoUc, and A.I. Taub, Ed., Vol 58, Materials Research Society, 1986, p. 309-343... 

Row85] Rowe, R.G. and Koch, E.F., Rapidly SoUdified Titanium Alloys Containing Cerium Sulfide and Oxysulfide Dispersions, in Rapidly Solidified Materials, PW. Lee and R.S. Carbonara, Ed., American Society for Metals, 1985, p. 115-120... 

Sas85 ] Sastry, S.M., Peng, T.C., and OT eal, J.E., Rapid Solidification and Powder MetaUurgical Processing of Titanium Alloys, in Modem Developments in Powder Metallurgy, Vol 16, Ferrous and Nonferrous Materials (Tbronto, Canada, June 1984), E.N. Aqua and C.I. Whitman, Ed., Metal Powder Industries Federation, 1985, p. 577-606... 

Wha86] Whang, S.H., Rapidly Solidified Titanium Alloys for High-lfemperature Applications, J. Mater. Sci., Vol 21, 1986, p. 2224-2238... 

Use Limitations. Beta C, like other beta titanium alloys, is highly susceptible to hydrogen pickup and rapid hydrogen diffusion during heating, pickling, and chemical milling. However, be-... 

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