Temperature Dependence of Mechanical Properties and Deformation Behavior of Austenite-Base High Mn steels

MasterHigh Mn steels have received great attention in recent years since they have excellent combination of high tensile strength and elongation. It is expected that these steels would exhibit good toughness at low temperatures due to their austenitic structures. However, most of high Mn steels have microstructure consisting of austenite with various volume fraction of other constituent phase such as ε-martensite and α’-martensite. Although the transformation induced plasticity (TRIP) and twinning induced plasticity (TWIP) are generally known as the dominant deformation mechanisms in high Mn steels, actual deformation behavior might be quite complex depending on the volume fraction of ε-martensite and α’-martensite. The objective of this research is to investigate the effect of constituent phases on the temperature dependence mechanical properties of high Mn steels. 17 wt% Mn steels with 0.1%C and 0.2%C have been chosen to have various volume fractions of austenite and ε–martensite. They have been subjected to internal friction, tensile and Chary impact tests at various temperatures. The steels show the deformation-induced phase transformation such as γ -> ε, γ -> α’ and γ -> ε -> α’ during tensile deformation. Such deformation mechanisms are dependent on the stacking fault energy, which is a function of chemical composition of the material, temperature and magnetic property. It shows that the Neel temperature (TN), where a paramagnetic to antiferromagnetic transformation occurs in γ and ε, plays an important role in controlling the deformation behavior of 17 Mn steels at low temperatures. Detailed deformation behavior of the steels has been investigated by EBSD and correlated with tensile and impact properties

Effect of Strain Rate on Deformation Behavior of Austenitic High Mn Steel at Cryogenic Temperature

DoctorIn recent years, austenitic high Mn steels have received a great deal of attention since they show an excellent combination of high strength and large ductility. It has been shown that the deformation behavior of these austenitic high Mn steels is strongly dependent on their stacking fault energies (SFEs); the steels show the transformation-induced plasticity (TRIP) for SFE ~45 mJ/m2 [4]. Mn and C effectively change the SFE and accordingly the steels containing (20-30) wt.% Mn and (0.4-1.2) wt.% C have SFEs in the range of 30 mJ/m2 and 40 mJ/m2 and usually exhibit TWIP phenomenon at room temperature, thus called as TWIP steels among various types of austenitic high Mn steels. An extraordinary combination of ductility and strength can be obtained in TWIP steels, where mechanical twinning γ ? γ`T proceeds gradually during deformation. The twinned crystal planes act as obstacles to dislocation motion, leading to dynamic Hall-Petch type strengthening. Considering that the application of these TWIP steels would be mostly in automobiles, the components made of TWIP steels would be subjected to not only quasi-static but also dynamic strain states such as during collision, but the effect of strain rate on the mechanical behavior of TWIP steels has seldom been studied and is not clearly understood. Understanding the behavior of TWIP steels at high strain rates is also important since these TWIP steels have a large potential for applications as structural components for several load bearing applications such as vessels, liquid nitrogen gas tank, etc. In addition, high strain rates will also play a role during sheet forming of TWIP steels. The objective of the present study is to study the effect of strain rate ranging from 10-3/s to 103/s at room temperature and cryogenic temperature on the deformation behavior of high Mn TWIP steel

Effects of strain rare and temperature on the mechanical properties and deformation behavior of high Mn TWIP steels

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Effect of Strain Rate on Deformation Behavior of High Mn TWIP Steel

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High Strain Rate Deformation Behavior of High Mn TWIP Steels at Cryogenic Temperature

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Effect of Constituent Phases on Low Temperature Deformation Behavior of Austenite-Base High Mn Steels

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Temperature dependence of mechanical properties and deformation behavior of austenite-base high Mn steels

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Effect of Microstructure on Low Temperature Mechanical Properties of Austenite-Based High Mn Steels

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High Strain Rate Deformation Behavior of High Mn Steels at Cryogenic Temperature

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The improvement of toughness at low temperature in ferritic Fe-Mn steels

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