Accession Number : AD0866645

Title :   Investigations to Develop Metal Alloys with Ultrafine Grain Size (Titanium with Improved Mechanical Properties).

Descriptive Note : Final rept. 1 Feb 69-31 Jan 70,

Corporate Author : FRANKLIN INST RESEARCH LABS PHILADELPHIA PA

Personal Author(s) : Jones, R. L.

Report Date : 31 JAN 1970

Pagination or Media Count : 55

Abstract : Experiments are described which were intended to elucidate the extent to which commercial purity titanium wire and sheet could be strengthened by the combined effects of interstitial content, grain size refinement and post recrystallization cold reduction. Procedures were developed which resulted in recrystallized grain sizes of the order of 0.5 microns. Two features found to be essential were cold reduction of at least 90% before recrystallization and the use of a rapid heat transfer technique (in this case molten lead annealing) for the recrystallization heat treatment. Grain refinement to this extent was found to lead to increases in strength (of up to 60 Ksi) and reduction in area at failure, accompanied by decreases (of up to a factor of two) in uniform elongation. The use of PRR was found to result in an additional strength increase (20-40 Ksi) and an additional uniform elongation decrease (a further factor of 2) with little effect on the reduction in area at failure. A program goal of a yield strength of 150 Ksi combined with adequate ductility was exceeded in the wire experiments but was not attained in the sheet experiments where difficulties were encountered in the achievement of the necessary initial 90% cold reduction. (Author)

Descriptors :   *GRAIN STRUCTURES(METALLURGY)), (*TITANIUM, ANNEALING, GRAIN SIZE, WIRE, SHEETS, RECRYSTALLIZATION.

Subject Categories : Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE