A process includes sintering hydrogenated titanium or titanium hydride (TiH 2 ) and/or Ti metal in a dynamically controlled hydrogen atmosphere with hydrogen partial pressure greater than 0.01 atmosphere and at elevated temperature, to form a sintered titanium material; equilibrate the sintered material at an equilibration temperature below the sintering temperature and above the phase transformations including eutectoid decomposition temperature for an equilibration time sufficient for the hydrogen within the sample to reach equilibrium and homogenize the sintered titanium material; holding the sintered titanium material at a hold temperature below the temperature of sintering and a hold time sufficient for phase transformations including eutectoid decomposition of the sintered titanium material; and heating the sintered titanium material under vacuum, inert atmosphere, or a combination of both at a hold temperature which is less than that of the sintering temperature, to form titanium metal, or a titanium metal alloy with fine or ultrafine grain sizes; where the dynamically controlled hydrogen atmosphere varies as a function of time and temperature throughout the thermal cycle and includes hydrogen during the sintering and phase transformations including eutectoid decomposition steps.

Powder metallurgy methods for the production of fine and ultrafine grain ti and ti alloys

A method of producing high purity, low oxygen content titanium powder utilizes a hydrided titanium powder crushed to desired percentage of particles of not more than a desired size. These hydrided particles are dehydrided by a slow heating process under partial vacuum to draw the hydrogen out of the particles with a minimum of sintering of the particles. The hydrided particles may be initially heated relatively rapidly, over a period of between about two hours and six hours to a temperature of between about 450° C. and 500° C. and then slowly over a period of four to five days to a temperature of between 650° C. and 700° C., all under a partial vacuum, until the hydrogen content of the powder reaches a desired value. The now dehydrided titanium powder is cooled, again crushed if and as necessary to break up any sintered particles, screened, and packaged. The method of the invention minimizes the sintering of the particles during the dehydriding process.

Method of producing titanium powder

The microstructure of alpha-2 and orthorhombic titanium aluminide alloy cast and ingot metallurgy articles is refined by: (a) hydrogenating the article at a temperature at or slightly below the β-transus temperature of the alloy; (b) cooling the article, under a positive partial pressure of hydrogen, to a temperature about 20 to 40 percent below the β-transus; and (c) dehydrogenating the article.

Method to refine the microstructure of α-2 titanium aluminide-based cast and ingot metallurgy articles

A hollow article is made by providing and diffusion bonding the opposing parts of an article made of an alpha-beta titanium alloy. Hydrogen is introduced into the surface of an internal cavity before, during, or after diffusion bonding. The article is heat treated with the hydrogen present, typically by solution treating and aging the hydrogen-containing bonded article. The result is the production of a microstructure at the internal surface of the cavity that is resistant to fatigue-crack initiation, while retaining a microstructure throughout the rest of the article that is resistant to fatigue-crack propagation. After heat treating, the hydrogen is removed from the article, and any further heat treating and other operations are completed.

Manufacture of fatigue-resistant hollow articles

The invention discloses a new preparation method of superfine Ti powders, belonging to the technical field of micro-nanometer Ti powder preparation. The invention solves the technical problem that a hydrogenation dehydrogenation (HDH) method in the prior art is difficult to prepare fine Ti powders as powder grains grow in the dehydrogenation process. The invention firstly proposes to take water soluble salt including Cl as a grain growth inhibitor. The preparation method of the superfine Ti powders is characterized by comprising the following steps of: carrying out hydrogenation and hydrogen permeation on a sponge Ti raw material to obtain a crisp Ti hydride raw material, mechanically crushing the crisp Ti hydride raw material into very tiny Ti hydride powders, then evenly mixing with a grain growth inhibitor aqueous solution, drying and dewatering in vacuum to obtain superfine Ti hydride powders coated with the grain growth inhibitor, and hydrogenating at high temperature in vacuum, washing and drying to obtain the superfine Ti hydride powders.

Preparation method of superfine Ti powders

According to the present invention, titanium and titanium alloy materials having a fine equiaxed microstructure are produced. A titanium, α titanium alloy or (α+β) titanium alloy material is hydrogenated in an amount of 0.02 to 2% by weight. If necessary, the hydrogenated material is subjected to pretreatment [i.e., heated above 700° C. (β transformation point)] and/or working (i.e., working at 450° to 950° C., or temperatures above β transformation point and below 1100° C.). The material is then aged at 10° to 530° C. or 10° to 700° C. (in the case of working at temperatures above β transformation point), and finally dehydrogenated and recrystallized to prepared a material having a fine equiaxed microstructure.

Process for preparing titanium and titanium alloy materials having a fine equiaxed microstructure

In the production of titanium and (α+β)-type titanium alloy materials, a material hydrogenated in an amount of 0.02 to 2% by weight of hydrogen is worked at a temperature of 450 to 900°C at a reduction of more than 60%, and the material is dehydrogenated and annealed in vacuum. The working of the titanium material is carried out at 450 to 800°C, and the working of the (α+β)-type titanium alloy material is carried out at 550 to 900°C. Furthermore, in the production of titanium, α-type titanium alloy, and (α+β)-type titanium alloy materials, a material hydrogenated in an amount of 0.02 to 2% by weight of hydrogen is subjected to a heat treatment wherein the material is heated at a temperature not lower than the β transformation temperature and then cooled, the material is worked at a temperature of 450 to 950°C at a reduction not lower than 20%, the material is dehydrogenated and annealed in the vacuum, the working of the titanium material is carried out at 450 to 800°C, the working of the α-type titanium alloy material is carried out at 600 to 950°C, and the working of the (α+β)-type titanium alloy material is carried out at 550 to 900°C.

Jin-Ichi C

Papers

Process for preparing titanium and titanium alloy materials having a fine equiaxed microstructure

Process for production of titanium and titanium alloy materials having fine equiaxial microstructure