US2948608A - Heat treatable alloys of titanium or zirconium - Google Patents

Description

Aug. 9, 1960 L. D. EsN IcK HEAT TREATABLE ALLOYS OF TITANIUM 0R ZIRCONIUM Filed Jan. 17, 1958 mwmzpz I n. a

PERCENT OXYGEN $79 INVENTOR United States Patent Ofi ice 2,948,608 Patented Aug. 9, 1960 HEAT TREATABLE ALLOYS F TITANIUM OR ZIRCONIUM Leroy D. Resnick, Silver Spring, Md., assignor to Chicago Development Corporation, Riverdale, Md., a corporation of Delaware Filed Jan. 17, 1958, Ser. No. 709,576

1 Claim. (Cl. 75-1755) This invention relates to heat treatable alloys of titanium or zirconium with the beta stabilizing element iron, and critical amounts of oxygen. It relates particularly to alloys of titanium and zirconium containing about 1% or less of iron and from about 0.03 to about 0.05% oxygen. It relates also to methods of heat treating these alloys without oxygen absorption which is necessary for my invention.

The alloys of titanium and zirconium with less than 0.03% oxygen are not effectively heat treatable, having the same properties whether slowly or rapidly cooled from the beta range.

My invention is based on the discovery that alloys of titanium or zirconium containing from 0.3 to 1% of iron and from 0.03 to 0.05 oxygen are heat treatable. Specifically, they are much harder and stronger when rapidly cooled from 1000 C. than when slow cooled from this temperature.

I will now illustrate my invention. Reference to the figure shows the hardness of titanium-iron alloys containing 0.05 iron and varying percentages of oxygen. The heavy line shows the hardness of the alloys rapidly cooled from 1000 C., and the dotted line the hardness of the alloys when slowly cooled from that temperature. It will be seen that alloys with from 0.03 to 0.05% oxygen are capable of substantial hardening from the slow cooled or annealed condition by heating to, and rapidly cooling from, 1000 C.

The results given in this example were obtained by heating in, and rapidly cooling from, an atmosphere of pure butane, and to insure an uncontaminated surface, '4 mils were ground from the surface after each heating.

To illustrate the necessity of carrying out the heat treating step of my invention without oxidation, I show in the following table the results of heat treating an alloy of 0.5% iron and 0.04% oxygen, in air, and in butane.

Time at temperature in the range 9001000 C. is not important. It is important only that the sample be heated through. At lower reheating temperatures, longer periods are required.

Having now described my invention in its most general terms, I will illustrate it by examples. In the following examples, the alloys used were all in the form of strip which had been produced from vacuum melted ingots by working with the rigorous exclusion of oxygen. I have found, however, that the results of the procedures illustrated are the same without respect to the physical form of the metal, which may be cast or wrought, provided, the oxygen content and the content of the alloying metal is within the limits set forth.

Example I DPH UTB, YP, Elongation Number lbs/sq. in. lbs/sq. in. (person 1n 1 in.)

Rapidly Cooled 400 192,000 175,000 14 Slow Cooled 158 84, 000 43, 000 40 Example II In this example, I proceed exactly as in Example I, except that I use an alloy of zirconium with 0.75% iron.

The results follow:

DPH UTS, YP, Elongation Number lbs/sq. ln. lbs/sq. in. (percent in 1 in.)

Rapidly Cooled 410 198,000 170,000 16 Slow Cooled-.. 85,000 45,000 38 What is claimed is: V

An alloy hardenable by at least 50 numbers Vickers by cooling rapidly the annealed alloy from a temperature of 900-1000 C., said alloy consisting of 0.3-1.0% iron, 0.03-0.05% oxygen, balance substantially all a metal selected from the group consisting of titanium and mum.

References Cited in the fileof this patent Preparation and Evaluation of Titanium Alloys, Battelle Memorial Institute, Summary Report, Part HI, May 18, 1948, to July 30, 1949; page 199 of specific interest.

The Constitution of the Titanium-Rich Alloys of Titanium, Iron, and Oxygen, Allen et al., Institute of Metals, Journal, vol. 82, September 1953-August 1954; pages 534-538.

A Preliminary Survey of Zirconium Alloys, Anderson et al., Bureau of Mines Report 4658, March 1950.

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