Superplastic Bonding and Ultrahigh Carbon Steel Laminated Composites.
Final rept. Sep 79-Sep 83,
STANFORD UNIV CA DEPT OF MATERIALS SCIENCE AND ENGINEERING
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Ferrous laminated composites based on ultrahigh carbon UHC steel have been successfully manufactured by rolling bonding below the A1 transition temperature. This procedure results in the development of sharp and discrete layer boundaries since no interdiffusion occurs during rolling. Good bonding is achieved because of the presence of ultrafine grains in the UHC steel. Mechanical properties of the composites have been evaluated for their charpy V-notch impact properties and for their superplastic characteristics. An extremely low ductile-to-brittle transition temperature, and very high shelf energies have been found both for ferrous laminated composites and for UHC steel laminates. This remarkably good behavior is shown to be a result of notch blunting within the laminates as a result of delamination. If the interlayer strength is improved by heat treatment, delamination does not take place and the impact properties are degraded. The mechanical properties of a ferrous laminated composite consisting of alternating layers of a superplastic UHC steel and non-superplastic I.F. iron, have been studies at intermediate temperatures. Superplastic behavior was approached in the laminated composite with values of the strain rate sensitivity exponent of as high as 0.3 measured and maximum tensile elongation of achieved.
- Laminates and Composite Materials
- Fabrication Metallurgy