Cryogenic Toughness through Microstructure Control in a Ferritic Fe-Ni-Alloy.
CALIFORNIA UNIV BERKELEY DEPT OF MATERIALS SCIENCE AND ENGINEERING
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This paper discusses the selection of composition and processing of a ferritic Fe-Ni-Ti alloy having a favorable combination of strength and toughness at cryogenic temperature. Criteria on alloy composition lead to the choice of low interstitial Fe-12Ni-0.25Ti. The alloy naturally has a favorable microstructure, but cryogenic toughness must be imparted through grain refinement. Several alternate procedures are identified. Four of these are discussed in detail, along with the resulting tensile properties at 77K, Charpy impact energies at 77K and 5K, and behavior in fracture toughness tests at 77K. Alloys are obtained having yield strengths to 150 KSI with impact toughness to 5K. Author
- Metallurgy and Metallography