US3004848A - Method of making titanium and zirconium alloys - Google Patents

Description

atent' lVlETHOD OF MAKINGTITANTUTVTANTT T fional Distillers and Chemical Corporation, New York,

N.Y., a corporation of Virginia No Drawing. Filed Oct. 2, 1958, Ser. No. 764,764 7 Claims. (Cl. 75-135) This invention relates to a new and useful process in the production of zirconium 'or titanium metal alloys and/or alloy powders in a substantially continuous man,- ner. More particularly, it relates to a combination process comprising low temperature reduction of zirconium or titanium tetrachloride in the presence of other metal halides and/or other metals with alkali metals and a heat treatment of the finely divided reaction product from the low temperature reduction to convert the metal to metallic zirconium or titanium alloy sponge or to nonreactive alloy powder.

This application is a continuation-in-part of Serial No. 569,968, filed March 7, 1956, now abandoned.

Although, for many applications in the powder metallurgy field, the hardness of alloys such as those of'tita-L nium is not critical, other factors present difficulties. At present, two types of methods are used for obtaining powdered titanium metal for use in powder metallurgy. One type employs a process in which the massive titanium metal is comminuted by grinding or crushing and the other treats titanium sponge with'hydrogen' to produce the hydride which is then decomposed to form molding powder. In either case, the powder thus obtained must then be mechanically mixed with the elements required to form the titanium alloys.

Alloys of titanium which contain small percentages of other metals are prepared by mechanically mixing titanium sponge with the alloying element'and then compressing the mixture into a consumable electrode for are: melting to an ingot. Double melting of the ingot is essen-' tial to obtain a completely homogeneous metal alloy. This extra arc melting step would not be required if the sponge and alloying metals could be obtained in analform and homogeneous mixture at the start.

For many applications, alloy powders are more important than pure zirconium or titanium sponge or powder. For instance, as described above, difliculties are encountered in preparing and maintaining uniform pow dered metal mixtures prior to pressing and sinteringthe parts formed in powder metallurgy. Another great advantage of powder metallurgy over the conventional methods, especially for expensive metals is that approximately 100% of the zirconium or titanium and the alloying elements end up in the finished article rather than the usual 50%. In this manner, for example, powdered titanium metallurgy is a good answer to the vital titanium scrap problem. Thus, with a suitable titanium alloy molding powder prepared as herein described it is feasible to produce, for instance, compressor blades using the new hot coining technique. In this process, a part is pressed and sintered to slightly over-size, then while still hot, at a temperature of around 900 C. the article is forged in a coining process which completely closes the pores and yields a very accurate massive titanium article.

In the Kroll process for metallic titanium, titanium tetrachloride is fed into the reactor which contains molten magnesium metal. Operating under such conditions, it is 3,904,848 Paitented Oct. 17,

"ice

impossible to reduce a mixture of titanium tetrachloride and other metal halides and thereby obtain a uniform metal spongecomposition. Another'ieason for segregation of metals during the reduction is the wicking action of the titanium sponge on the molten magnesium. This is particularly significant since this process normally utilizes for reduction 85% or less of the magnesium placed in the reactor. The remaining amount (about is present at the end of the reduction as free magnesium and remains dissolved in the titanium sponge in a. non-uniform manner.

Substitution of sodium for magnesium under similar E conditions does not solve this difficulty of non-uniformity.

Likewise, electrolytic processes do not serve satisfactorily for production of zirconium and titanium alloys. The position of the alloying elements in the electromotive series, or more specifically the single electrode potential of the metallic ions, indicate that either zirconium or titanium would electroplate to the practical exclusion of the alloying elements or, vice versa, depending on the alloying metals involved.

It is the object of this invention to describe a process whereby a metal sponge and/or non-reactive metal powneous alloy ingots and parts.

ders may be produced containing the zirconium or the titanium and the alloying metals in substantially molecular mixture, thus eliminating the costly and time consuming techniques now required for producing homoge- Even more particularly, it has as an additional objective the production of a sponge directly usable'in powder metallurgy without the difiicult comminuting processes presently required to obtain the desired metalparticle size for use in powder metallurgy. Sponge or alloy powder is produced in proper screen analysis.

Thus, the invention comprises essentially a low temperature sodiumreduction process and a heat treating operation wherein required alloying elements are incorporated directly into final sponge or powder by using mixtures of the halides of the alloying metals or of the alloying metals with the zirconium or titanium chlorides.

Alloying metals such as aluminum and/or vanadium, chromium, tin, molybdenum, iron or manganese are incorporated uniformly into the sponge by using zirconium on reduction, a uniform mixture of finely divided metal tetrachloride or titanium tetrachloride containing necessary amounts of the halide or the halide mixture of the particular desired alloying metal or of theparticular desired alloying metal itself. Thus, there is obtained,

powders which on sintering would produce a sponge or non-reactive powder of uniform composition with respect to the zirconium or titanium components and particularly with respect to the alloying metal content.

This process is especially'well adapted and designed to produce such alloys and alloy powders. Operating as herein described, mixtures of compounds of two or more metals are reduced concurrently or simultaneously to.

produce especially prepared and finely divided alloy powders. nium and iron; titanium and manganese; titanium and tin;

titanium, chromium and iron; titanium and aluminum and the like can readily be obtained. Many other mixtures of metal powders can be thus obtained as desired. In general, commercial titanium alloys contain relative minor proportions, that is, no more than 10% total of the other alloying elements. Among the more common.

alloying elements for titanium are aluminum, manganese, vanadium, chromium and tin. For zirconium the most Alloy powders of titanium and copper; titaQ usual alloying metal is tin (2-3%). Typical examples of the more numerous titanium alloys are the following:

Titanium with 8% manganese.

Titanium with 4% aluminum and 4% manganese.

Titanium with 6% aluminum and 4% vanadium.

Titanium with aluminum and 1% iron and 1% chromium.

Titanium with 5% aluminum and 1% each of iron,

chromium and molybdenum.

Titanium with 3% manganese and 1% each of molybdenum, vanadium, chromium and iron.

Titanium with 5% aluminum and 2 /2 tin.

Titanium with 3% aluminum and 5% chromium.

The use of an alkali metal, and in particular sodium, permits operation of a process in which there is a separation, or at least a partial separation of the chemical reduction step from the sponge forming step whereby the chemical reduction step is at least in part carried out at any temperature above the melting point of the alkali metal and below the melting point of the alkali metal halide by-product. When SOCllllIl'l is used, the by-product salt is sodium chloride. It has also been found that at relatively low temperatures the product of the reaction is a free flowing finely divided mixture of reduction products and by-product alkali metal halide produced according to the following equations resulting in mixtures of titanium sub-halides (with substantially no titanium being present in the event less than stoichiometric amounts of sodium are used that is 25% to 50% of the amount required for theoretical reduction to the metal):

(a) 2Na+TiCl TiCl +2NaCl (b) Na+TiCl TiCl +NaC1 in actual operation an incomplete reduction according to Equations a and 1) yields a solid partially reduced intermediate reduction product. As the finely divided, solid product fills the reactor, having started with a partial charge of finely divided salt as a heel," further product is withdrawn, preferably continuously, by means of, for example, a screw conveyor leading away from the reaction vessel from a location on the side of the vessel near the top flange. 1

Another embodiment of the invention involved reacting less than the stoichiometric arnount of sodium with the zirconium or titanium tetrahalides and the alloying metal halides so that a solid, finely divided mixture consisting substantially of the lower valence halides of zirconium or titanium and the alloying metals is formed. This reduction is carried out at any temperature above the melting point of sodium but below the melting point of the reaction mixture. The remaining sodium required for stoichiometric reduction is then added and allowed to react with suiiicient heat being liberated to melt the by-product salt and cause the finely divided metals produced to form an inert spongy mass of the metals in intimate, uniform mixture.

A typical reduction system for the partially reduced mixtures is described below. The reduction reactor consists of a cylindrical vessel in which a rectangular or anchor type stirrer operates, which stirrer is capable of mamtaining the solid reaction medium of finely divided powder and by-product salt in an agitated state. Appropriate amounts of sodium and zirconium tetrachloride or titanium tetrachloride with the desired halides of the alloying metals or the metals themselves are fed into this reactor at such controlled rates that the temperature therein is in the range of from above the melting point of sodium to the melting point of the mixture, but preferably in the 150-450 C. range. The capacity of the reactor to produce product will, of course, vary with the surface area and size of the vessel walls and/ or other means provided to dissipate the heat of the reduction reaction of the metal halides with the alkali metal. As the solid substantially dry reaction product fills the reaction vessel, it is withdrawn either continuously or discontinuously by means of, for instance, a screw conveyor system attached to the side of the reaction vessel. The dry product is allowed to fall or is passed into a sintering vessel for completion of reduction and heat treatment of the resulting alloy powder at temperatures above the melting point of the reaction mixture or of the alkali metal lay-products. The entire reduction and heat treatment operations are preferably carried out in aninert atmosphere, for instance, under a blanket of an inert gas such as argon or helium.

The required amount of sodium necessary for completion of reduction is added and the finely divided mixtures of metals and, by-product salt is then brought to a term perature above the melting point of sodium chloride and held for a controlled period of time by, for example, immersing the sintering pot in a furnace maintained at the appropriate temperature. The metal alloy-salt mixture is preferably maintained at a temperature of about 850- lO50 C. for a period of from 1 up to about 5 to 20 hours. At the completion of the heat treatment, the sintering vessel and contents are removed from the furnace and allowed to cool to room temperature after which the alloy sponge is removed and recovered, Molten salt may be drained from the metal alloy sponge if desired, prior to cooling. The product from this process can be freed from by-product salt by washing with water with production of a metallurgical grade alloy sponge.

Several variations which are quite satisfactory for operating this invention are described below although this list is not to be considered as limiting the invention in any way. For instance, zirconium or titanium tetrachloride together with side streams of halides of the selected alloying metals are simultaneously and continuously or semicontinuously fed into the low temperature reduction vessel with amounts of sodium to partially reduce the zirconium or titanium tetrachloride and other metal halides to a free flowing powder consisting substantially of subhalides and by-product salts which may or may not contain any free metals. The only requisite here is that the powder to free flowing, easily transferable, and essentially non-volatile at the temperatures of handling.

If this operation is used, the predetermined amount of sodium to complete the reduction may be first introduced into the bottom of the sinter vessel and the partially reduced powder mixture placed on top of the solidified sodium. At any rate, the reaction in which completion of the reduction occurs should proceed as rapidly as possible in order to avoid crystal formation and yield a homogeneous sponge. Upon reaching about C. after placing in the sintering furnace the reduction reaction rapidly completes itself with the release of enough heat to bring the whole reaction mass to 800950 C. in 15 to 60 minutes depending on the level of reduction permitted in the first stage.

This mode of separation of the reduction reaction into two stages is of distinct advantage in the production of titanium or zirconium alloy sponge since alloying elements are thoroughly mixed in at an essentially non-volatile state and are reduced to metal in situ by sodium as it vaporizes upward and throughout the mass. The speed with which this last part of the reaction takes place is also a great factor in preventing segregation. Very little time for crystal growth is allowed so a uniform metal alloy sponge free of crystals results.

A second method of operation which is especially adaptable Where the alloying halide is not soluble, involves the reduction of TiCl or ZrCL; to the dichloride or other intermediate subhalide stage, but at which stage the parti-' ally reduced sub-halides are finely divided and free howing powders. This mixture is then blended with the powdered alloying halide either as a separate operation or in the heat treating vessel itself which contains the requisite amount of sodium to complete the reduction in the heating furnace. After the alloying metal halides have been added and admixed therewith, the sintering process is the same as in the process described above.

While some inorganic halides, of the desired alloying metals are soluble in and miscible with titanium and zirconium tetrachlorides others are essentially insoluble. Therefore, it is frequently advantageous to use a combination of the above described procedures. That is, the soluble metallic halidesare added with the titanium tetrachloride and the insoluble alloying solid halides are added as a powder to the charge just before sintering.

Still another mode of operation is carried out by combining a part or all of the alloying metals in the form of finely divided metal powders either simultaneously with the sodium reduction in the first or low temperature stage, or preferably by combining, with good mixing, the free metal powders into the partially reduced mixture in the sintering vessel just prior to the sintering operation. In this case, only that amount of sodium is placed in the sintering pot which is needed to complete the reduction of the zirconium or titanium component of the alloy in the high temperature or sintering stage. In actual practice, the alloying metals or the halides of the alloying metals can be combined with the low temperature reduction product at any point after the reduction step and prior to the actual final sintering operation.

' By operating at a sodium deficiency in the reduction step it is meant that there is added thereto only enough sodium to form the subhalides such as subchlorides of the halides of higher valency, for instance:

More broadly, the reaction may be interrupted at the first or low temperature stage at, for instance, 25% reduction, 50% reduction, 75% reduction, 90% reduction, and the like. The only important requirement at this stage of the process is that the reaction product must be an easily mechanically transportable powder which is insensitive to temperature, i.e., it is not likely to form melts which solidify to concrete-like materials should the reaction temper- 5 out the electrode.

1 arate additions of columbiurn, tantalum and aluminum being required before a homogeneous ingot could be ob tained. One advantage of these directly produced alloy sponges is thatthese difiiculties are avoided and a double or, in

5 some cases, multiple arc melting at the ingot stage is unnecessary since this is only practical on a relatively small,- experimental scale. As pointed out above, it has been found that when the alloying elements are fed into the melting crucible, as a side stream,'e.g., along with zirconium or titanium sponge, or mixed with the conium or titanium sponge and compressed to form a consumable electrode, at least a second melting is required to insure homogeneity in the ingot. With the alloy sponges and alloy powders provided according to this invention, these meltingttechniques are unnecessary.

The degree of non-melting segregation in;an ingot is afiected'by the particle size of the alloy or mixture. As the particle size decreases, the extent of segregation de creases. Ingots made with a mixture of the metal powders show less segregation than ingots made from mixtures of the metals scrap. V v

' It is not known, generally, or in any particular case, of alloy composition just what degree of fineness of particle size of these metal powder mixtures can be used and-will not result in segregation and will thus provide a homogeneous ingot using a conventional two-stage melting technique.

Itis generally uneconomical to use relatively high cost metal powders, singly or in mixtures and to provide these 40 in particle sizes small enough to permit production of homogeneous-alloy ingots using conventional melting ature, momentarily and in isolatedzones become a due to a momentary unbalance of raw material feeds.

After the sponge growth phase of the process is completed, and this usually requires from 1 up to 5 to 20 hrs. at 850-900 C. up to 1100 C., the sintering or heat treating vessel is removed from the furnace and preferably, the major part of the by-product salt removed either by tapping or by at least partially inverting the vessel and allowing the molten salt by-product to drain away from the sponge which may or may not adhere lightly to the bottom and/or sides of the sintering vessel. The whole mass is then allowed to cool to room temperature. Thereafter, the vessel is opened and the sponge containing some residual salt is removed. The sponge with the contained salt is then crushed to suitable size, leached with water I of the constituent halides can be prepared and fed s1- which may contain a small amount of acid, if desired, to neutralize any alkali which may be present from the slight excesses of the reducing alkali metal and/or to solubilize and stabilize against oxidation and hydration any trace amounts of'diand tri-chlorides of titanium or zirconium and other incompletely reduced metallic halides. The washed alloy sponge is then dried and is ready for use.

Homogeneity in commercial titanium and zirconium alloy ingots has long presented a serious problem. Arc melting is preferably used, since this melting technique, when properly used, is the only one which results in uncontaminated alloys. However, alloy ingots produced in this type furnace are often severely segregated.

For small ingots, homogeneity can be achieved by melting and remelting on both sides of a pancake in a special furnace. This is also limited, to small ingots because of very limited depth of melting which can be achieved.

. Consumable electrode arc melting can also be done in which electrodes areforrned by pressing and sintering the 7 Using this process, is possible to obtain and employ the finely divided powders necessary for homogeneity in the alloys without the expense and difficulties of producing them from sponge, and with superior results in making of homogeneous alloy ingots.

' Another great advantage is that metal powders of the necessary alloying free metals do not need to he provided in a puresta'te, only the pure chlorides are necessary and these are much more easily prepared. However, in

" some cases as pointed out above, some of the alloying elements can best be added as metal powders. In actual operation of the invention, the halides of the alloying metals that are sufficiently soluble will be mutually dissolved and added as a solution so that'a master mixture multaneously into the low temperature reduction stage, For example, vanadium chloride and stannic chloride are typical of metal halides which are soluble in titanium tetrachloride. Since zirconium tetrachloride is a solid, all alloying elements would be added as side streams rather than in solution for zirconium alloy sponge.

Powder metallurgical applications require minus 20 to plus 200 mesh material. Thus, another advantage of this process for titanium and zirconium alloy sponge, lies in the fact that in contrast to Kroll magnesium sponge, alloy sponge by this sodium reduction technique can be corhminuted easily because of its lower bulk densityto powders suitable for powder metallurgy. This is partic ularly important in the case, of titanium alloys where sponge produced commercially by magnesium reduction of titanium tetrachloride cannot, except with great difficulty be broken down mechanically to particles suitable for powder metallurgy. For example, one method for converting magnesium produced titanium sponge to pow der is to convert it to titanium hydride by reacting with hydrogen at elevated temperatures and then to decompose this hydride by further heating to obtain a suitable powder. This lengthy and expensive processing is avoided completely by the herein described process.

Operating according to this new process, the alloy sponges whichresult are not mixtures but substantially true alloys. This overcomes a difficult existing problem not only in the homogeneous and complete mixing of alloying powders but also in keeping them mixed during handling operations prior to pressing into the green mold.

It is to be understood that this process operates to produce a wide variety of metal alloys. Actually the mixture of metal halides fed to the reduction step or the alloying metal added can be varied over almost any range to produce the desired alloy composition in controlled and exact proportions. Such an alloy sponge results in a great saving in time to the fabricator from several standpoints. It is not necessary to handle and feed several metal powders of varying purities, all requiring repeated analyses. The metal alloy product is purer and more free of interstitial elements, since metal powders always tend to become oxidized and thus carry oxide film layers into the final ingot.

The true alloy sponges permit the powder metallurgical formation by hot coining techniques of many parts such as compressor blades which otherwise must be machined from titanium alloy billets with the usual 50% and greater losses. Powder. metallurgy operations with such alloy sponges give a coined part with almost no waste in fabrication. This means a tremendous saving in cost of the finished parts.

Example 1 Sodium is fed at a uniform rate into a low temperature reduction vessel for carrying out the first step of the process. A constant heel consisting of a mixture of solid, finely divided reduction products is maintained by continuously or at least intermittently withdrawing product from the vessel as fast as additional product is formed. Simultaneously and at least intermittently titanium tetrachloride is metered into the reduction zone there being added 8% less sodium than the amount of sodium required, for stoiohiometric reduction. After a period of 17.7 hours, a quantity of 62.6 parts of TiCl and 34.8 parts of sodium have been added to the reactor vessel. The resulting product is withdrawn as a salt titanium mixture and is placed in a sintering vessel containing 4.5 parts free sodium. At this point the charged sintering vessel is disconnected from the reduction vessel and connected to a weighed hopper containing 6.55 parts of resublimed and finely divided aluminum chloride. The aluminum chloride is added into the sintering vessel under an argon atmosphere and the hopper disconnected. The sintering vessel of size of about 18" diameter by 36" high is then turned end-overend in a turning device to insure thoroughly intermixing of the aluminum chloride with the products of partial reduction of the titanium tetrachloride and the excess sodium. After such mixing, the entire mixture in the sintering vessel is placed in the sintering furnace and heated to 850 to 900 C. for a period of 6 hours. The sintered product is then removed from the furnace and the vessel turned on its side to drain the product salt away from the sponge (which adheres lightly to the bottom) formed during the sinter operation. vAfter cooling, the sponge is removed, ground to 10 meshsize, washed free of salt with slightly acidulated water, and washed with water on a centrifuge. The excess water is spun from the sponge which is dried in a vacuum drying oven. A. quantity of alioy sponge amounting to 14.0 parts, 81% yield, is recovered which has a hardness of 190 Brinell and an aluminum content of 7.8%.

Example 2 Operating in a manner analogous to that of Example 1, sodium (64.5 parts) is added to the reduction kettle over a period of 16.9 hours. During this period, at a uniform rate, 120.5 parts of titanium tetrachloride is also introduced which leaves 5.67 parts of sodium unreacted. The hopper is charged with 3.06 parts of anhydrous manganese chloride (equivalent to 1.1 parts sodium) and 6.60 parts of aluminum chloride (equivalent to 4.55 parts sodium). Both metal salts are previously finely ground in a ball mill under an argon atmosphere. This salt mixture is introduced into the sintering vessel and mixed thoroughly. This sintering vessel is placed into the sintering furnace for the reduction of the newly added chlorides. The reaction mixture is heated for a period of 10 hours at a temperature of 925 C. The alloy sponge, isolated as in Example 1, amounts to 30.1 parts which is a' 90.1% yield. The alloy sponge contains 4.0% each of manganese and aluminum with the diiierence being titanium.

Example 3 Quantities of sodium (64.0parts) and a mixture of titanium tetrachloride and vanadium tetrachloride, 118 parts and 5.0 parts respectively, are added to thelow temperature reduction kettle simultaneously and continuously at uniform rates. The halide mixture is preheated and volatilized into the reaction zone as a gas vided reduction product.

wherein the reduction to the metal takes place at a temperature of 200 to 250 C. A period of 16.7 hours is required for the addition of these quantities of materials and the continuous withdrawal of the solid, finely di- The amount of sodium added is in excess (5.1 parts) over that needed to reduce the 118 parts of TiCl, and the 5.03 parts of VCl This excess sodium is equivalent to 9.8 palts of AlCl This amount of aluminum chloride, finely ground, is now introduced under argon into the sintering vessel and thoroughly mixed by turning the sinter vessel end-over-end as described in Example 1 above. The sintering vessel is now heated under an argon blanket to a temperature of 900 C. for a period of 15 hrs. The vessel is then removed from the furnace and placed on its side, to permit draining away of most of the by-product salt before cooling. After cooling, the alloy sponge is removed, ground, leached free of salt, dried and analyzed. Alloy sponge amounting to 28 parts equivalent to an 84.5% yield, is recovered containing approximately 6% aluminum and 4% vanadium.

Example 4 Operating as described in Example 1, 120.5 parts of TiCl and 61.1 parts of sodium are fed simultaneously into the reduction vessel over an 18.5 hour period at .a reduction temperature of 250 C. The finely divided product is continuously withdrawn as formed but there is maintained aheel of 15 to 20 parts of the solid reaction mixture in the reduction vessel. At the conclusion of this step in the process the sintering vessel, into which the reduction mixture has been transferred, is disconnected from the reduction vessel and connected to the argon-filled hopper which contains 1.0 parts of finely divided aluminum powder (-300 mesh) and 5.08 parts of powdered CrCl This mixture is introduced into the sintering vessel. Then the contents of the sintering vessel are thoroughly mixed by turning end-over-end in a turning device. After this, the vessel is heated in the furnace to 900 C. for a period of 10 hrs. to effect sponge growth and alloying of the powdered aluminum. The sponge is isolated as in the above examples, by leaching with water, slightly acidified at first with hydrochloric acid to prevent attack by oxygen of the air on trace quantities of titanium subhalides present in the sponge. The resulting alloy sponge of titanium with chromium and aluminum amounts to 29 parts which is an 89% yield. This alloy contains approximately 3.1% aluminum and 3.5% chromium.

While there are above disclosed but a limited number of embodiments of the invention herein presented, it is possible to produce still other embodiments without departing from the inventive concept herein disclosed, and it is desired therefore that only such limitations be imposed on the appended claims as are stated therein.

What is claimed is:

1. A process for the production of an alloy of a metal selected from the group consisting of titanium and zirconium which comprises the following separate steps: (A) reducing a tetrahalide of a metal from the group consisting of titanium and zirconium with an amount of sodium at least sufiicient to reduce said tetrahalide to a corresponding metal halide of lower valence, but insutficient for stoichiometric reduction to the metal, thereby controlling the reaction temperature within a range from V the melting point of the sodium up to the melting point of the reaction mixture, said reaction mixture comprising halides of lower valence selected from the group consisting of titanium and zirconium subhalides and the corresponding sodium halide, and forming an easily stirred, solid, finely divided reaction mixture which is stirred during the reduction reaction; (B) introducing an alloying material selected from the group consisting of a halide of an alloying metal and an alloying metal into said process in any step up to the initiation of the subsequent slntering period; (C) recovering said solid, finely divided mixture and subjecting'it to reaction with the required amount of additional sodium for stoichiometric reduction of all halides present in said mixture to form metal alloy of said alloying reactant and said metal selected from the group consisting of titanium and zirconium and utilizing the resulting heat of the reduction reaction in heating the mixture containing said alloy to a sintering temperature above the melting point of the sodium halide by-product produced, so as to lower the time required to attain a sintering temperature for said alloy; (D) maintaining said sintering temperature for a sufiicient period of time to complete sintering of said metal alloy and to produce a massive metal alloy of said alloying metal and said metal selected from the group consisting of titanium and zirconium; and (E) isolating the metal alloy from the resulting reaction mixture.

2. The process of claim 1 wherein the amount of sodium employed in step (A) is from about 25 to 90% by weight of the stoichiometric amount required for re-' duction of said halide to the appropriate alloy.

3. The process of claim 1 wherein the alloying material is a metal which is introduced into said solid, finely divided mixture of halides of low valence and the corresponding sodium halide just prior to subjecting said solid, finely divided mixture to reaction with the required additional sodium in step (C).

4. The process of claim 1, wherein the alloying material is a halide of any alloying metal which is introduced into said solid, finely divided mixture of halides of lower valence and the corresponding sodium halide just prior to subjecting said solid, finely divided mixture to reaction with the required additional sodium in step (C).

10 5. A process for the production of an alloy of a metal selected fi'om the groupconsisting of titanium and zirconium which comprises the following separate steps: (A) reducing a tetrachloride of a metal from the group 1 consisting of titanium and zirconium with an amount of sodium at least suflicient to reduce said tetrachloride to a corresponding metal chloride of lower valence, but insufficient for stoichiometric reduction to the metal, thereby controlling the reaction temperature within a range of about ISO-450 C., said reaction mixture comprising chlorides of lower valence selected from the group consisting of titanium and zirconium subchlorides and sodium chloride, and forming an easily stirred, solid, finely divided reaction mixture which is stirred during the reduction reaction; (B) introducing an alloying material selected from the group consisting of a chloride of an alloying metal and an alloying metal into said process in any step up to the initiation of the subsequent sintering period; (CTrecoWe ringsaid solid; *fineiy divided mixture and subjecting it to reaction with the required amount of additional sodium for stoichiometric reduction of all chlorides present in said mixture to form a metal alloy of said alloying reactant and said metal selected from the group consisting of titanium and zirconium and utilizing the resulting heat of the reduction reaction in heating the mixture containing said alloy to a sintering temperature above the melting point of the sodiumrchloride produced, so as to lower the time required to attain a sintering temperature for said alloy; (D) maintaining said sintering temperature for a suflicient period of time to complete sintering of said metal alloy and to produce a massive metal alloy of said alloying metal and said metal selected from the group consisting of titanium and zirconium; and (E) isolating the metal alloy from the resulting reaction mixture. 1

6. The process of claim 5, wherein the alloying material is a metal which is introduced into said solid, finely divided mixture of chlorides of lower valence and sodium chloride just prior to subjecting said solid, finely divided mixture to reaction with the required additional sodium in step (C).

7. The process of claim 5, wherein the alloying material is a chloride of any alloying metal which is introduced into said solid, finely divided mixture of chlorides of lower valence and sodium chloride just prior to subjecting said solid, finely divided mixture to reaction with the required additional sodium in step (C).

References Cited in the file of this patent UNITED STATES PATENTS 2,205,854 Kroll June 25, 1940 2,766,113 Chisholm et a1 Oct. 9, 1956 2,826,493 Garrett et a1. Mar. 11, 1958 2,827,371 Quin Mar. 18, 1958 2,828,199 Findlay Mar. 25, 1958 2,848,319 Keller et a1 Aug. 19, 1958 FOREIGN PATENTS 386,621 Great Britain Feb. 16, 1933 686,845 Great Britain Feb. 4, 1953

Claims (1)

1. A PROCESS FOR THE PRODUCTION OF AN ALLOY OF A METAL SELECTED FROM THE GROUP CONSISTING OF TITANIUM AND ZIRCONIUM WHICH COMPRISES THE FOLLOWING SEPARATE STEPS: (A) REDUCING A TETRAHALIDE OF A METAL FROM THE GROUP CONDIDTING OF TITANIUM AND ZIRCONIUM WITH AN AMOUNT OF SODIUM AT LEAST SUFFICIENT TO REDUCE SAID TETRAHALIDE TO A CORRESPONDING METAL HALIDE OF LOWER VALENCE, BUT INSUFFICIENT FOR STOICHIOMETRIC REDUCTION TO METAL, THEREBY CONTROLLING THE REACTION TEMPERATURE WITHIM A RANGE FROM THE MELTING POINT OF THE SODIUM UP TO THE MELTING POINT OF THE REACTION MIXTURE, SAID REACTION MIXTURE COMPRISING HALIDES OF LOWER VALENCE SELECTED FROM THE GROUP CONSISTING OF TITANIUM AND ZIRCONIUM SUBHALIDES AND THE CORRESPONDING SODIUM HALIDE, AND FORMING AN EASILY STIRRED, SOLID, FINELY DIVIDED REACTION MIXTURE WHICH IS STIRRED DURING THE REDUCTION REACTION, (B) INTRODUCTING AN ALLOYING MATERIAL SELECTED FROM THE GROUP CONSISTING OF A HALIDE OF AN ALLOYING METAL AND AN ALLOYING METAL INTO SAID PROCESS IN ANY STEP UP TO THE INTIATION OF THE SUBSEQUENT SINTERING PERIOD, (C) RECOVERING SAID SOLID, FINELY DIVIDED MIXTURE AND SUBJECTING IT TO REACTION WITH THE REQUIRED AMOUNT OF ADDITIONAL SODIUM FOR STOICHIOMETRIC REDUCTION OF ALL HALIDES PRESENT IN SAID MIXTURE TO FORM METAL ALLOY OF SAID ALLOYING REACTANT AND SAID METAL SELECTED FROM THE GROUP CONSISTING OF TITANIUM AND ZIRCONIUM AND UTILIZING THE RESULTING HEAT OF THE REDUCTION REACTION IN HEATING THE MIXTURE CONTAINING SAID ALLOY TO A SINTERING TEMPERATURE ABOVE THE MELTING POINT OF THE SODIUM HALIDE BY-PRODUCT PRODUCED, SO AS TO LOWER THE TIME REQUIRED TO ATTAIN A SINTERING TEMPERATURE FOR SAID ALLOY, (D) MAINTAINING SAID SINTERING TEMPERATURE FOR A SUFFICIENT PERIOD OF TIME TO COMPLETE SINTERING OF SAID METAL ALLOY AND TO PRODUCE A MASSIVE METAL ALLOY OF SAID ALLOYING METAL AND SAID METAL SELECTED FROM THE GROUP CONSISTING OF TITANIUM AND ZIRCONIUM, AND (E) ISOLATING THE METAL ALLOY FROM THE RESULTING REACTION MIXTURE.