Accession Number : AD0786229

Title :   Comparative Fracture Toughness Testing of Cryogenic Alloys at Liquid Helium Temperature.

Descriptive Note : Technical rept.,

Corporate Author : CALIFORNIA UNIV BERKELEY DEPT OF MATERIALS SCIENCE AND ENGINEERING

Personal Author(s) : Jin,Sungho ; Hwang,S. K. ; Morris,J. W. , Jr

Report Date : AUG 1974

Pagination or Media Count : 24

Abstract : Fracture behavior of the Fe-12Ni-0.25Ti alloy grain refined through thermal cycling was studied down to liquid helium temperature using a simple method of cryogenic fracture toughness testing. Comparison tests were also made with two other common cryogenic alloys. Ultrafine grained Fe-12Ni-0.25Ti alloy, which is 100% ferritic, behaved in a ductile manner similar to 304 austenitic steel. It was shown that the ductile-brittle transition temperature of the ferritic steel specimen can be suppressed below liquid helium temperature by grain refinement even in the presence of a sharp crack. Yield strength at liquid nitrogen temperature, and yield strength at liquid helium temperature were obtained. (Modified author abstract)

Descriptors :   *Fracture(Mechanics), *Iron alloys, *Cryogenics, Yield strength, Titanium alloys, Test methods, Grain size, Nickel alloys

Subject Categories : Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE