δ-TRIP Steel

S. Chatterjee, M. Murugananth and H. K. D. H. Bhadeshia

Abstract

A combination of neural networks and genetic algorithms has been used to design a TRIP-assisted steel in which the silicon concentration is kept low. In this context the steel has a novel microstructure consisting of δ-ferrite dendrites and a residual phase which at high temperatures is austenite. This austenite can, with appropriate heat-treatment, evolve into a mixture of bainitic ferrite and carbon-enriched retained austenite. The steel has been manufactured and tested to reveal a tensile strength of about 1~GPa and a uniform elongation of 23%.

Materials Science and Technology 23 (2007) 819-827.

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• Ph.D. thesis.
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Micrographs

δ-TRIP steel, Fe 0.41C 2.42Mn 0.46Si 1.57Al 0.26P 0.42Cu wt%, as cast.	δ-TRIP steel, Fe 0.41C 2.42Mn 0.46Si 1.57Al 0.26P 0.42Cu wt%, as cast.	δ-TRIP steel, Fe 0.41C 2.42Mn 0.46Si 1.57Al 0.26P 0.42Cu wt%, heat treated.
δ-TRIP steel, Fe 0.41C 2.42Mn 0.46Si 1.57Al 0.26P 0.42Cu wt%, heat treated.	δ-TRIP steel, Fe 0.41C 2.42Mn 0.46Si 1.57Al 0.26P 0.42Cu wt%, heat treated	δ-TRIP steel, Fe 0.41C 2.42Mn 0.46Si 1.57Al 0.26P 0.42Cu wt%, as cast.
δ-TRIP steel, Fe 0.41C 2.42Mn 0.46Si 1.57Al 0.26P 0.42Cu wt%, as cast.	δ-TRIP steel, Fe 0.41C 2.42Mn 0.46Si 1.57Al 0.26P 0.42Cu wt%, as cast.	δ-TRIP steel, Fe 0.41C 2.42Mn 0.46Si 1.57Al 0.26P 0.42Cu wt%, as cast.
δ-TRIP steel, Fe 0.41C 2.42Mn 0.46Si 1.57Al 0.26P 0.42Cu wt%, as cast.	δ-TRIP steel, Fe 0.41C 2.42Mn 0.46Si 1.57Al 0.26P 0.42Cu wt%, as cast.	δ-TRIP steel, Fe 0.41C 2.42Mn 0.46Si 1.57Al 0.26P 0.42Cu wt%, as cast.

Fractographs of Tensile Test Specimens

Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.	Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.	Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.
Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.	Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.	Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.
Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.	Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.	Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.
Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.	Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.	Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.
Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.	Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.	Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.
Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.	Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.	Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.
Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.	Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.	Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.
Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.	Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.	Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.
Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.	Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.	Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.
Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.	Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.	Fractograph of δ-TRIP steel, as cast, tensile tested at ambient temperature.

Fractograph of δ-TRIP, as-cast sample, tested at 125 C.

Fractograph of δ-TRIP, as-cast sample, tested at 125 C.