Accession Number:

AD0602478

Title:

OBSERVATIONS ON DELAYED CRACKING IN WELDED STRUCTURES OF UNALLOYED TITANIUM SHEET,

Descriptive Note:

Corporate Author:

BATTELLE MEMORIAL INST COLUMBUS OHIO DEFENSE METALS INFORMATION CENTER

Personal Author(s):

Report Date:

1964-04-29

Pagination or Media Count:

9.0

Abstract:

A brief study of delayed fracture in a seam-welded titanium panel is summarized in this memorandum. Examination of the fracture surface with electron microscopy showed that the material cleaved, failing in a brittle manner. Although the nature of the embrittlement was not clearly defined, titanium hydride phase was suspected as a prime contributor to failure. Even though the hydrogen content of the titanium was only 65 ppm, hydride embrittlement was thought to have occurred from precipitation of hydride platelets on crystal planes oriented normal to welding stresses. Other work, briefly discussed in the memorandum, has confirmed that hydride platelets in titanium can be oriented by stress and that tensile ductility of Zircaloy which behaves similarly with respect to hydrogen, to titanium depends upon hydride orientation. Stress-relief annealing of welded titanium structures is recommended wherever possible to minimize embrittlement by stress-oriented hydrides. Author

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Distribution Statement:

APPROVED FOR PUBLIC RELEASE