Effect of strain deformation rates on forming the structure and mechanical properties of high-manganese austenitic TWIP steels

2016 ◽  
Vol 2 (4) ◽  
pp. 490-502 ◽  
Author(s):  
Leszek Adam Dobrzański ◽  
Wojciech Borek ◽  
Janusz Mazurkiewicz
Keyword(s):  
Mechanical Properties ◽  
High Manganese ◽  
Twip Steels

The Study of Type Twin Annealing in High Mn Steel

2011 ◽  
Vol 148-149 ◽  
pp. 1085-1088
Author(s):  
Gholam Reza Razavi
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Room Temperature ◽  
Twip Steel ◽  
Manganese Steel ◽  
High Manganese ◽  
High Manganese Steel ◽  
Twip Steels ◽  
Mn Steel

TWIP steels are high manganese steel (Mn: 17% - 35%) which are used for shaping car bodies. The structure of this kind of steels remains austenite even in room temperature. Due to low SFE (Stacking Fault Energy) twinning of grains is governing reformation mechanism in this kind of steels which strengthen TWIP steel. Regarding heat treatment influences on mechanical properties of TWIP steels, in this paper we discuss twinning phenomenon resulting from this kind of treatment. For this, following casting and hot rolling processes, we anneal the steel at 1100°C and different time cycles and study its microstructure using light microscope. The results showed that with decreasing grain size the number of twin annealing added And four types of annealing twin in the microstructure, in the end they all become one twin and then turn into grain.

Improvement of the Mechanical Properties of High Manganese Steels by Combination of Precipitation Hardening and Mechanical Twinning

2006 ◽  
Vol 15-17 ◽  
pp. 852-857 ◽  
Author(s):  
Mathieu Iker ◽  
D. Gaude-Fugarolas ◽  
Pascal J. Jacques ◽  
Francis Delannay
Keyword(s):  
Mechanical Properties ◽  
Morphological Evolution ◽  
Carbide Precipitation ◽  
Mechanical Twinning ◽  
Carbon Steels ◽  
High Manganese ◽  
Twip Steels ◽  
Annealing Cycle ◽  
Kinetics Of Precipitation ◽  
Kinetics Of

Twinning-Induced Plasticity steels (TWIP steels) are extensively studied due to their ultra-high strain-hardening rate, that brings about a remarkable combination of ductility and strength. Twinning can be observed in high manganese-carbon steels. This paper considers hardening by combination of mechanical twinning with carbide precipitation. The kinetics of precipitation and the morphological evolution of carbides with annealing time were studied for two different TWIP steels with high manganese and carbon contents. The steels are first cold-rolled and then annealed at 800°C for recrystallization and carbide precipitation. Depending on the steel composition, the kinetics of precipitation and the morphology of the carbides are quite different. The influence of the annealing cycle on the mechanical properties has also been assessed. The results are used to discuss the influence of composition, stacking fault energy (SFE) and carbide precipitation on twinning. We show that the usual criteria based on the SFE only are not sufficient to characterize the twinning ability of a steel.

Structural features and strength behavior of TRIP/TWIP steels

2020 ◽  
pp. 5-18
Author(s):  
D. V. Prosvirnin ◽  
◽  
M. S. Larionov ◽  
S. V. Pivovarchik ◽  
A. G. Kolmakov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Thermomechanical Processing ◽  
Maximum Load ◽  
Structural Features ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
Structural And Functional Properties ◽  
Twip Steels ◽  
The Creation

A review of the literature data on the structural features of TRIP / TWIP steels, their relationship with mechanical properties and the relationship of strength parameters under static and cyclic loading was carried out. It is shown that the level of mechanical properties of such steels is determined by the chemical composition and processing technology (thermal and thermomechanical processing, hot and cold pressure treatment), aimed at achieving a favorable phase composition. At the atomic level, the most important factor is stacking fault energy, the level of which will be decisive in the formation of austenite twins and / or the formation of strain martensite. By selecting the chemical composition, it is possible to set the stacking fault energy corresponding to the necessary mechanical characteristics. In the case of cyclic loads, an important role is played by the strain rate and the maximum load during testing. So at high loading rates and a load approaching the yield strength under tension, the intensity of the twinning processes and the formation of martensite increases. It is shown that one of the relevant ways to further increase of the structural and functional properties of TRIP and TWIP steels is the creation of composite materials on their basis. At present, surface modification and coating, especially by ion-vacuum methods, can be considered the most promising direction for the creation of such composites.

scholarly journals Effect on Mechanical Properties of Heat Treated High Manganese Austenitic Cast Iron

2016 ◽  
Vol 78 ◽  
pp. 01081
Author(s):  
A.K. Muzafar ◽  
M.M. Rashidi ◽  
I. Mahadzir ◽  
Z. Shayfull
Keyword(s):  
Mechanical Properties ◽  
Cast Iron ◽  
High Manganese ◽  
Heat Treated ◽  
Austenitic Cast Iron

Fatigue Behavior of High Manganese TWIP Steels and of Low Alloy Q&P Steels for Car-Body Applications

2014 ◽  
Vol 783-786 ◽  
pp. 713-720
Author(s):  
Paolo Matteis ◽  
Giorgio Scavino ◽  
R. Sesana ◽  
F. D’Aiuto ◽  
Donato Firrao
Keyword(s):  
Heat Treatment ◽  
Room Temperature ◽  
Fatigue Behavior ◽  
Austenitic Steels ◽  
Fracture Mechanisms ◽  
High Manganese ◽  
Cold Forming ◽  
Austenitic Structure ◽  
Plasticity Effect ◽  
Twip Steels

The automotive TWIP steels are high-Mn austenitic steels, with a relevant C content, which exhibit a promising combination of strength and toughness, arising from the ductile austenitic structure, which is strengthened by C, and from the TWIP (TWinning Induced Plasticity) effect. The microstructure of the low-alloy Q&P steels consists of martensite and austenite and is obtained by the Quenching and Partitioning (Q&P) heat treatment, which consists of: austenitizing; quenching to the Tqtemperature, comprised between Msand Mf; soaking at the Tppartitioning temperature (Tpbeing equal to or slightly higher than Tq) to allow carbon to diffuse from martensite to austenite; and quenching to room temperature. The fatigue behavior of these steels is examined both in the as-fabricated condition and after pre-straining and welding operations, which are representative of the cold forming and assembling operations performed to fabricate the car-bodies. Moreover, the microscopic fracture mechanisms are assessed by means of fractographic examinations.

scholarly journals Dependence of Grain Size on Mechanical Properties and Microstructures of High Manganese Austenitic Steel

2014 ◽  
Vol 81 ◽  
pp. 143-148 ◽  
Author(s):  
Xiaoyun Yuan ◽  
Liqing Chen ◽  
Yang Zhao ◽  
Hongshuang Di ◽  
Fuxian Zhu
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Austenitic Steel ◽  
High Manganese ◽  
High Manganese Austenitic Steel

The Mechanical and Deformation Behavior of TWIP Steel Prepared by Directional Solidification

2014 ◽  
Vol 783-786 ◽  
pp. 761-765 ◽  
Author(s):  
Dan Wang ◽  
Kun Wang ◽  
Zi Mu Shi ◽  
Fu Sheng Han
Keyword(s):  
Mechanical Properties ◽  
Strain Hardening ◽  
Twip Steel ◽  
True Strain ◽  
Longitudinal Direction ◽  
True Stress ◽  
Grain Structure ◽  
Directionally Solidified ◽  
Twip Steels ◽  
Columnar Grain

A directionally solidified TWIP steel (Fe-25Mn-2.5Al-2.5Si) was prepared by liquid metal cooling technology. The microstructure and mechanical behavior were examined and compared with usually solidified samples. The directionally solidified TWIP steel shows a typical columnar grain structure, and the maximum true stress and true strain along the longitudinal direction of the sample are 1060MPa and 71% respectively. As a comparison, the usually solidified samples shows an equiaxed grain microstructure with the maximum true stress and true strain of only 994MPa and 58%, respectively. Moreover, the two solidification modes also lead to very different strain hardening behavior, particularly in the changes of strain hardening rate with strain. This suggests that the grain boundary plays a key role in the mechanical properties of TWIP steels, and changing the grain boundaries can be effective to improve the comprehensive mechanical properties of TWIP steels.

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