Accession Number : AD0775510
Title : Grain Refinement through Thermal Cycling in an Fe-Ni-Ti Cryogenic Alloy.
Descriptive Note : Technical rept.,
Corporate Author : CALIFORNIA UNIV BERKELEY DEPT OF MATERIALS SCIENCE AND ENGINEERING
Personal Author(s) : Jin,S. ; Morris,J. W. , Jr. ; Zackay,V. F.
Report Date : JAN 1974
Pagination or Media Count : 40
Abstract : A thermal cycling technique which allows the grain refinement of Fe-12Ni-0.25Ti alloy in four cycles has been developed. The process consists of alternate annealing in gamma range and (alpha + gamma) range with intermediate air cooling. The transformation, microstructures and cryogenic mechanical properties on each cycling step are described. Due to the ultrafine grain size, the ductile-brittle transition temperature of this ferritic alloy in Charpy impact testing was suppressed below 6K. In fracture toughness testing at 77K, the mode of fracture was altered from brittle quasi-cleavage to complete ductile rupture through the grain refining. (Modified author abstract)
Descriptors : *Iron alloys, *Nickel alloys, *Titanium alloys, *Grain size, Thermal cycling tests, Microstructure, Diffusion, Low temperature
Subject Categories : Properties of Metals and Alloys
Distribution Statement : APPROVED FOR PUBLIC RELEASE