Deformation mechanisms and mechanical properties of hot rolled Fe-Mn-C-(Al)-(Si) austenitic steels

Mechanical properties of high Mn austenitic Fe-26.5Mn-3.6Al-2.2Si-0.38C-0.005B, Fe-30.0Mn-3.1Al-1.9Si and Fe-18.9Mn-0.62C-0.02Ti-0.005B (in mass%) steels after different solution treatments were investigated. The results show that the solution treatment has a significant influence on microstructure and mechanical properties of the investigated steels. By appropriate solution treatment the product of tensile strength (Rm) and total elongation (A50) of the hot rolled steel can be improved from ~40000-55000 MPa% to ~55000-65000 MPa% depending on the chemical composition. A solution treatment with a very high temperature, e.g. at 1100°C for the Fe-18.9Mn-0.62C-0.02Ti-0.005B steel, results in a significant increase in the hcp-martensite fraction during quenching. This deteriorates the ductility of the steel. A solution treatment at low temperature in the austenitic range, e.g. at 700 °C for the Fe-18.9Mn-0.62C-0.02Ti-0.005B steel, results in a decrease in the grain size of the steel. This suppresses the hcp-martensitic transformation during cooling. Colour etchings and EBSD measurements revealed the mechanisms contributing to the overall plasticity of the investigated steels on the microscale. The plasticity of the Fe-26.5Mn-3.6Al-2.2Si-0.38C-0.005B and Fe-30.0Mn-3.1Al-1.9Si steels is produced mainly by TWIP mechanism under the examined experimental conditions, whereas for the Fe-18.9Mn-0.62C-0.02Ti-0.005B steel TWIP and TRIP mechanisms occur with different intensity depending on the temperature of the tensile test. For predicting deformation mechanism the stacking fault energies of the investigated steels were calculated by using a thermochemical model. The results show a good correlation between the predicted deformation mechanisms and the experimentally determined deformation mechanisms.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2008

Author dc:creator

• Phiu-on, Kriangyut

Contributors dc:contributor

• Bleck, Wolfgang

• info:eu-repo/classification/ddc/620
• TWIP-Stahl
• Ingenieurwissenschaften
• TWIP steel
• high manganese steel
• EBSD

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

eng

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-112948%22

OAI record oai:identifier

https://publications.rwth-aachen.de/oai2d?verb=GetRecord&metadataPrefix=oai_dc&identifier=oai%3Apublications.rwth-aachen.de%3A50402