Dissemination of IT for the Promotion of Materials Science (DoITPoMS)

DoITPoMS Micrograph Library Full Record for Micrograph 740

Full Record for Micrograph 740

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Micrograph no
740
Brief description
TRIP steel annealed at 775°C for 5 mins and then hold at 400°C for 40s for austenite stabilization
Keywords
alloy Link to MATTER Glossary entry for alloy, bainite Link to MATTER Glossary entry for bainite, metal, retained austenite, TRIP steel
Categories
Metal or alloy
System
Fe-C-X   Link to phase diagram
Composition
Fe, C 0.15, Mn 1.5, Si 1.5 (wt%)
Standard codes
Reaction
Processing
The steel was annealed at 775°C and then hold at the intermediate bainitic holding temperature of 400°C for only 40 s and then water quenched.
Applications
Sample preparation
The sample was etched using the two-stage step etching technique.
Technique
Reflected light microscopy
Length bar
20 μm
Further information
The microstructure shows martensite (straw-coloured), retained austenite (white) and some M-A constituents. Martensite volume fraction is higher than the steel which was hold for 150s at 400°C and cooled. Since the austenite is low in C-content for such a low holding time at 400°C, most of the austenite is transformed to martensite during cooling from 400°C to room temperature.
Contributor
Dr Amar K De
Organisation
ASPPRC, Metallurgical and Materials Engineering Department, Colorado School of Mines
Date
22/04/03
Licence for re-use
Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales
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