US2818337A - Titanium alloys - Google Patents

Description

United States Patent TITANIUM ALLOYS Earl F. Swazy, Richard H. Freyer, and Lee S. Busch, Indianapolis, Ind., assignors, by mesne assignments, to Mallory-Sharon Titanium Corporation, Indianapolis, Ind., a corporation of Delaware No Drawing. Application September 4, 1953, Serial No. 382,183, now Patent No. 2,786,756, dated March 26, 1957, which is a division of application Serial No. 138,516, January 13, 1950, now Patent No. 2,661,286, dated December 1, 1953. Divided and this application February 15, 1957, Serial No. 644,433 g 4 Claims. (Cl. 7 175.5)

This invention relates generally to alloys of titanium and has particular reference to alloys consisting of titanium, carbon and silicon, alone, or in combination with another element, to form a quaternary alloy with titanium predominating. This application is a divisional application of Serial No. 382,183, filed September 4, 1953, now Patent No. 2,786,756, dated March 26, 1957, which in turn is a division of application Ser. No. 138,516, filed January 13, 1950, now Patent No. 2,661,286, dated December 1, 1953. I

An object of the present invention, therefore, is to provide wrought, ductile alloys of titanium.

Another object of the present invention is to provide a wrought, ductile alloy of titanium, carbon and silicon.

Still another object of the invention is to provide quaternary alloys of titanium.

Yet another object of the invention is to provide alloys of titanium consisting of titanium, carbon and silicon having greater resistance to oxidation at elevated temperatures than pure titanium and exhibiting good hardness characteristics thereof.

Another object of the invention is to provide an alloy of titanium consisting of titanium, carbon and silicon and any one of the following elements: aluminum, copper, vanadium, chromium, boron, tungsten and iron.

Yet another object of the invention contemplates a method of preparing quaternary alloys of titanium consisting of the ternary alloys of carbon, silicon and titanium, to which is added an element from the group; aluminum, copper, chromium, vanadium, boron, tungsten or iron.

The invention, in another of its aspects, relates to the novel features and principles teaching the objects of the invention and to the novel principles employed herein whether or not these features and principles may be used in said object or in said field.

It is found that alloys of titanium, silicon and carbon with titanium predominating as a ternary alloy, or as an alloy to which may be added another element such as aluminum, chromium, copper, vanadium, boron, tungsten or iron provides a resistance to oxidation at elevated temperatures greater than that of pure titanium. Such alloys provide ductile, strong alloys of titanium and exhibit good corrosion resistance and high hardness characteristics at elevated temperatures. These alloys are usually manufactured by melting and casting in a graphite retort under an inert or neutral atmosphere; for example, argon, or in a vacuum. Further, the alloys may also be prepared by powder metallurgy methods. Thus, as an example, alloys containing .1% to 10% silicon, .2% to 2% carbon with the balance titanium, as compared to pure titanium, are characterized by having a higher tensile strength, equivalent ductility, slightly higher electrical resistivity, much .992% S111- .477% Car: con-.47% bon-B al- Carbonlance Tita- Balance nium Titanium Ultimate Tensile Strength 105, 000 121, 500 Elongation in 2-.. 12. 5 12. 5 Resistivity X1O- 76.5 10- Moreover, alloys, such as above, are characterized by a unique response to heat treatment. Upon quenching from 1000" C., these alloys do not harden appreciably (most alloys of titanium which contain metals forming stable carbides do harden on quenching). However, as the tensile strength is lowered to 113,500 p. s. i., the elongationincreases to 16.5%. In the as forged condition, the hardness at 600 C. increases from 0 Rockwell A to 32 Rockwell A when quenched. These changes are apparently caused by the presence of large amount of B titanium (body centered cubic) which is not transformed to a on fast cooling from 1000 C.

Again, in resistance to scaling tests at 900 C., an alloy containing 992% silicon was three times as effective as that for titanium containing .47% carbon. The results revealed a .536% increase in weight for the silicon alloy and 1.89% for the titanium alloy containing carbon only.

As stated, the ternary alloys formed of titanium, silicon and carbon may be combined with one of the elements: aluminum, copper, chromium, vanadium, boron or tungsten to form quaternary alloys. Thus, such an alloy consisting of titanium, copper, silicon and carbon exhibits the characteristics recited previously for the above alloys; i. e., ductility, high resistance to oxidation, better corrosion resistance, higher hardness, etc.

These alloys (titanium, copper, silicon and carbon) may be manufactured by melting and casting under an inert or neutral atmosphere (for example, argon) er in a vacuum. The alloys may also be prepared by powder metallurgy methods. A preferred method would thus consist in mixing copper and silicon, in massive or powder form, with titanium in sponge or powder form and melting and casting in graphite. The source of the carbon is the crucible and the amount is easily controlled by varying the time that the charge is molten. The alloys are preferably forged in air at temperatures between 300 C. and 900 C. but may be hot or cold worked by the usual methods known to the art.

The quaternary alloys of titanium, copper, silicon and carbon, herein described, may be made containing small but significant amounts of copper, silicon and carbon: for example, up to 10% copper; up to 10% silicon; and up to 2% carbon with the balance being titanium. The lower limit for these alloys is 0.1% copper; 0.1% silicon; 0.1% carbon and the balance titanium. A practical range of composition may be 1% to 5% copper; 0.5% to 3% silicon; 0.3% to 0.7% carbon and the balance titanium.

Such alloys prepared by this invention have the following minimum properties:

The-following chart is useful in depicting the constituents of theabove described alloys.

A'lloy table While the present invention as to its objects is merely illustrative and not exhaustive in scope and since many widely difierent embodiments of the invention may be made Without departing from the scope thereof, it is intended that all matter contained in the above description be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. Alloys containing from 0.1% to 10% copper, from 0.1% to 5% silicon, from 0.1% to 2% carbon, and the balance being substantially all titanium.

2. Alloys containing from 0.1% to 10% copper, from 0.1% to 5% silicon; from 0.1% to 2% carbon and the balance being substantially all titanium, said alloys being quench hardenable and susceptible to precipitation heat treatment.

Anny Ti Si C, 3. Alloys of titauiumas in claim 2 having the followpercent percent percent 111g minimum propert1es:

(1) Ti, Si, o 99. 7-88 .110 .2-2 AS (3) Ti, S1, O on 99. 7-78 1-10 1-2 1- 10%Cl1 Quenchgd As Hot tromtiQO Forged C. to Thus, it is seen that by the present invention primary, 1,100- 0. ductile, ternary alloys of titanium, silicon and carbon may be formed presenting characteristics substantially Ultimate Tensile Strength .p. s. 1-. 125,000 150,009 f t t Elongation in 2 peroent 8 3 supeilorto pure t1tar1ium 1n matters 0 resis ance o OX1 a- Modulus f Elasmltynfl mp, in m lsxmt tion, resistance to corrosion and high hardness. In add1- Electrical Reslstlvity X tion, these ternary alloys may be combined with copper. Thus, a basic ternary alloy consists of from .1% to 10% 4. Alloys as described in claim 3 characterized by hardsilicon; from .2% to 2% carbon with the remainder being nose at elevated temperatures up to 600 C. in excess of substantially all titanium. Again, an alloy, according to this invention may be fabricated of titanium, silicon, carbon and copper. In such an alloy, silicon and copper each may be present in amounts up to 10%; carbon up to 2%; with the remainder thereof being titanium.

those of titanium containing carbon only or of pure tita nium.

No references cited.

Claims (1)

1. ALLOYS CONTAINING FROM 0.1% TO COPPER, FROM 0.1% TO 5% SILICON, FROM 0.1% TO 2% CARBON, AND THE BALANCE BEING SUBSTANTIALLY ALL TITANIUM.