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AssigneeThe United States of America as represented by the United States Department of Energy
InventorsRobert C. Anderson, Jack M. Jones, Thomas G. Kollie
Estimating the term…
The present invention is directed to the fabrication of an article of uranium-2.4 wt. % niobium alloy in which the linear thermal expansion in the direction transverse to the extrusion direction is less than about 0.98% between 22.degree. C. and 600.degree. C. which corresponds to a value greater than the 1.04% provided by previous extrusion operations over the same temperature range. The article with the improved thermal expansion possesses a yield strength at 0.2% offset of at least 400 MPa, an ultimate tensile strength of 1050 MPa, a compressive yield strength of at least 0.2% offset of at least 675 MPa, and an elongation of at least 25% over 25.4 mm/sec. To provide this article with the improved thermal expansion, the uranium alloy billet is heated to 630.degree. C. and extruded in the alpha phase through a die with a reduction ratio of at least 8.4:1 at a ram speed no greater than 6.8 mm/sec. These critical extrusion parameters provide the article with the desired decrease in the linear thermal expansion while maintaining the selected mechanical properties without encountering crystal disruption in the article.
An extruded article of uranium-2.4 wt.% niobium characterized by a yield strength at 0.2% offset of at least 400 MPa, an ultimate tensile strength of at least 1050 MPa, a compressive yield strength at 0.2% offset of at least 675 MPa, an elongation in 25 mm of at least 25% and a linear thermal expansion of less than 0.98% in a direction transverse to the extrusion over a temperature range of 22.degree. C. to 600.degree. C.
A method for extrusion-forming a uranium alloy article of uranium-2.4 wt.% niobium that is characterized by a linear thermal expansion of less than 0.98% in a direction transverse to the direction of extrusion over a temperature range of 22.degree. C. to 600.degree. C., a tensile yield strength at 0.2% offset of at least 400 MPa, a tensile strength of at least 1050 MPa, a compressive yield strength at 0.2% offset of at least 675 MPa, and an elongation of at least 25% in 25.4 mm comprising the steps of:
Dependencies are inferred from the claim text.