US2688537A - Titanium-molybdenum-iron alloys - Google Patents

Description

Patented Sept. 7, 1954 TITAN IUM-MOLYBDEN UM-IRON ALLOYS Charles M. Craighead, Columbus, Ohio, assignor, by mesne assignments, to Battelle Development Corporation, Columbus, Ohio, a corporation of Delaware No Drawing. Application February 9, 1952, Serial No. 270,889

1 Claim. 1

i This invention relates to titanium-base alloys and, more particularly, to titanium-base alloys containing molybdenum and iron.

Recently, it has become generally recognized that titanium metal possesses valuable properties which render it desirable for various structural uses and for other purposes. For example, the metal has an excellent strength/weight ratio, good corrosion properties, and is useful for hightemperature applications. However, the various properties of titanium metal are not ordinarily subject to adjustment, as is often necessary in order that specific requirements imposed by particular applications be met. For this reason, and for the purpose of improving the properties of the base titanium metal, it is desirable to produce titanium-base alloys which possess desired properties in the required degree, or which will respond to heat treatment, or to other chemical and metallurgical processes, to produce enhanced properties and characteristics.

It is, therefore, an object of this invention to provide titanium-base alloys containing molybdenum and iron.

It is another object of this invention to provide titanium-molybdenum-iron alloys having desirable properties for structural or other purposes.

Still another object of this invention is to produce titanium-molybdenum-iron alloys which are responsive to heat treatment.

Other objects and advantageous features of the present invention will become apparent from the following detailed description.

In general, this invention relates to alloys of titanium containing molybdenum and iron, and, particularly, to those alloys containing from about 0.5% molybdenum to about 12% molybdenum, and from about 0.5% iron to about 12% iron.

However, the maximum quantities of molybdenum and iron may not be present in this alloy concurrently. The reason for this is that such an alloy is too brittle for structural use, and the strength/weight ratio is too low for structural use. Therefore, while the ranges of molybdenum and iron are as stated, the further limitation that the total of iron and molybdenum content must not be in excess of also exists.

A preferred range of from about 2% to about 8% molybdenum, and from about 2% to about 8% iron has also been established. In the case of this preferred range, there is no limitation on the total of the quantities of iron and molybdenum which may be present.

It has previously been discovered that the alloying of titanium with certain amounts of molybdenum produces alloys having improved strength and hardness properties, as compared with unalloyed titanium. These alloys are disclosed and described in co-pending application Serial No. 188,887. For instance, an alloy containing 5% molybdenum, and the balance titanium, as the intended composition, had a tensile strength of 144,900 p. s. i., an elongation (as measured in per cent for a 1-inch length) of 6.5 per cent and a Vickers hardness of 268.

It has been previously discovered also that the alloying of titanium with certain amounts of iron produces alloys having improved strength and hardness properties, as compared with unalloyed titanium. These alloys are disclosed and de-" scribed in co-pending application, Serial No. 188,886. For instance, an alloy containing 2% iron, and the balance titanium, as the intended composition, had a tensile strength of 146,500 p. s .i., an elongation (as measured in per cent for a 1-inch length) of 8.5, and a Vickers hardness of 305.

It has now been further discovered that unalloyed titanium may be benefited by the addition of prescribed'amounts of molybdenum and iron.

Table I below is a tabulation of typical mechanical properties of the alloys of this invention. The properties listed were measured on specimens which were in the "as-hot-rolled (at 1450" F.) condition,

TABLE I M echamcal properties Composition 1 Tensile Elongation, Strength, Percent in V. H. N. Percent Percent p. s. i. l-inch Mo e 1 Balance titanium.

From Table I above it will be apparent that the titanium-base, molybdenum-iron alloys possess excellent strength properties far in excess of the pure titanium metal, and also generally far in excess of the binary titanium-molybdenum alloys or binary titanium-iron alloys. The present alloys are seen also to exhibit good hardness properties with ductility sufficient to permit working.

That the alloys of the present invention respond to heat treatment is indicated by the data in Table II, wherein it will be noted that thehardness is generally increased by aging at 750 F. and the tensile strength is also increased by aging, at the same temperature, for lower alloy additions.

TABLE II M echam'cal properties As-hot-rolled at 1 450 F. and aged Composition 4 hours 9'';

Per- Per- Tensile Elongation, cent cent Strength, Percent in V. H. N Mo Fe p. s. l. i-lnch 1 Balance titanium.

It will be apparent that new and useful alloys of titanium with molybdenum and iron have been 4 discovered and are herein disclosed. As has been shown, these alloys have mechanical properties suitable for structural uses and are also responsive to heat treatment. Moreover, indications are that they have valuable corrosion-resistant and high-temperature properties.

It is, therefore, desired to claim the alloys of this invention as hereinafter set forth.

What is claimed is:

An alloy consisting essentially of from about 2% to about 8% molybdenum, from about 2% to about 8% iron, and. the balance titanium, said alloy being characterized by a combination of high strength and ductility in the as-hot-rolled (at 1450 F.) condition substantially as shown in Table 1.

References Cited in the file of this patent FOREIGN PATENTS Country Date Germany Mar. 24, 1942 OTHER REFERENCES Number