Effects of ferrite volume fraction on the tensile deformation characteristics of dual phase twinning induced plasticity steel

2014 ◽  
Vol 53 ◽  
pp. 99-105 ◽  
Author(s):  
A. Imandoust ◽  
A. Zarei-Hanzaki ◽  
S. Heshmati-Manesh ◽  
S. Moemeni ◽  
P. Changizian
2017 ◽  
Vol 140 (2) ◽  
Author(s):  
B. Ravi Kumar ◽  
Vishal Singh ◽  
Tarun Nanda ◽  
Manashi Adhikary ◽  
Nimai Halder ◽  
...  

The authors simulated the industrially used continuous annealing conditions to process dual phase (DP) steels by using a custom designed annealing simulator. Sixty-seven percentage of cold rolled steel sheets was subjected to different processing routes, including the conventional continuous annealing line (CAL), intercritical annealing (ICA), and thermal cycling (TC), to investigate the effect of change in volume fraction, shape, and spatial distribution of martensite on tensile deformation characteristics of DP steels. Annealing parameters were derived using commercial software, including thermo-calc, jmat-pro, and dictra. Through selection of appropriate process parameters, the authors found out possibilities of significantly altering the volume fraction, morphology, and grain size distribution of martensite phase. These constituent variations showed a strong influence on tensile properties of DP steels. It was observed that TC route modified the martensite morphology from the typical lath type to in-grain globular/oblong type and significantly reduced the martensite grain size. This route improved the strength–ductility combination from 590 MPa–33% (obtained through CAL route) to 660 MPa–30%. Finally, the underlying mechanisms of crack initiation/void formation, etc., in different DP microstructures were discussed.


2018 ◽  
Vol 736 ◽  
pp. 209-218 ◽  
Author(s):  
Manashi Adhikary ◽  
Arnab Chakraborty ◽  
Anindya Das ◽  
Venugopalan T ◽  
Ravi Kumar B

2020 ◽  
Vol 10 (4) ◽  
pp. 503-513
Author(s):  
Sohail Ahmad ◽  
Xiangyu Wang ◽  
Liming Fu ◽  
Javed Ahmad ◽  
Waseem Abbas ◽  
...  

A dual phase (martensite–austenite) low carbon nickel-manganese transformation-induced plasticity (TRIP) steel was fabricated by heavily warm rolling (HWR), and the effect of annealing on the phase fraction, mechanical properties and tensile deformation behavior of the heavily warm rolled (HWRed) steel was investigated. The results showed that the reverse transformation of γ-austenite from α′-martensite occurs and that the γ-austenite volume fraction (VA) decreases from 91% to 55% as the annealing temperature increases from 400 °C to 800 °C, respectively. The HWRed steel annealed at 400 °C exhibits a high strength-high ductility combination with yield strength of 706 MPa, ultimate tensile strength (UTS) of 1573 MPa, total elongation (TEL) of 21.6%, and the product of the strength and elongation (PSE: UTS×TEL) is 34 GPa%. These excellent mechanical properties are principally attributed to the formation of a large volume fraction of austenite (γ) by the reverse transformation and subsequent TRIP effect during tensile deformation. It was found that the HWRed and annealed steels exhibit a special tensile behavior with a large yielding strain followed by pronounced strain hardening. The tensile curve can be readily divided into three obviously different stages. The strain-induced martensite (SIM) transformation (γ -α′) occurs in the early yielding deformation stage and in the intermediate rapidly hardening deformation stage, indicating that the TRIP effect dominates the process of these two stages. However, the retained γ-austenite remains very stable, and no TRIP effect is observed in the final hardening deformation stage. The load-unload reload (LUR) test was performed to evaluate the back stress (σb) hardening effect during tensile testing. It is believed that the pronounced strain hardening behavior after yielding is mainly associated with the σb enhancement induced by the strain partitioning between the soft retained γ-austenite and the hard α′-martensite due to the SIM transformation during tensile deformation.


2011 ◽  
Vol 418-420 ◽  
pp. 1222-1227
Author(s):  
Lu You Yue ◽  
Zhong Fu Huang ◽  
Zhen Liang He ◽  
Man Guo Jiang ◽  
Wei Chen

The tensile tests of DP590 dual-phase steel tailor-welded blanks were carried out at different temperatures and strain rates. Quantitative analysis of metallographic was utilized to study the microstructure evolution of the base metal area and the weld zone of the tensile fracture. By combining the microstructure evolution model with the secondary development technologies of ABAQUS, the microstructure evolution of dual-phase steel tailor-welded blanks was simulated during warm tensile tests. The results show that, with the temperature increasing and strain rate decreasing, the dynamic recrystallization volume fraction of ferrite increases, and the martensite transform into equiaxed ferrite gradually. The results of microstructure simulation are in good agreement with experimental results.


2016 ◽  
Vol 838-839 ◽  
pp. 267-271 ◽  
Author(s):  
Shohei Koizumi ◽  
Junya Kobayashi ◽  
Goroh Itoh

Currently liners of high-pressure hydrogen storage container for fuel cell vehicles are manufactured from the 6061 aluminum alloy pipes through spinning at elevated temperatures. Since the surroundings of the containers are reinforced with a large amount of high-cost CFRP, the use of 6066 or 6069 aluminum alloy with higher strength than 6061 is demanded to lower the cost of the container. However, the formability of these aluminum alloys at elevated temperatures has not been elucidated yet. In this study, tensile deformation characteristics of 6066 and 6069 aluminum alloys at temperatures ranging from 25 to 550°C were investigated. The total elongation of 6066 aluminum alloy was higher than that of 6069 aluminum alloy at 450°C. This may be caused by the lower volume fraction of constituent particles. The flow stresses of the two alloys were almost the same, and were decreased with increasing testing temperature. The increase in elongation and decrease in strength observed in the two alloys were attributable to dynamic recovery.


2010 ◽  
Vol 638-642 ◽  
pp. 2992-2997 ◽  
Author(s):  
Hidefumi Date

The martensite induced in three types of austenitic stainless steel, which indicate the different stability of the austenitic phase (γ), were estimated by the resistivity measured during the tensile deformation or compressive deformation at the temperatures 77, 187 and 293 K. The resistivity curves were strongly dependent on the deformation mode. The volume fraction of the martensite (α’) was also affected by the deformation mode. The ε phase, which is the precursor of the martensite and is induced from the commencement of the deformation, decreased the resistivity. However, lots of defects generated by the deformation-induced martensite increased the resistivity. The experimental facts and the results shown by the modified parallelepiped model suggested a complicated transformation process depending on each deformation mode. The results shown by the model also suggested a linear relation between the resistivity and the martensite volume at the region of the martensite formation. The fact denoted that the resistivity is mostly not controlled by the austenite, ε phase and martensite, but by the defects induced due to the deformation-induced martensite.


2021 ◽  
Author(s):  
Gamri Hamza ◽  
Allaoui Omar ◽  
Zidelmel Sami

Abstract The effect of the morphology and the martensite volume fraction on the microhardness, the tensile, the friction and the wear behavior of API X52 dual phase (DP) steel has been investigated. Three different heat treatments were used to develop dual phase steel with different morphologies and with different amounts of martensite: Intermediate Quenching Treatment/Water (IQ); Step Quenching Treatment (SQ) and direct quenching (DQ). Tribological tests are conducted on DP steels using a ball-on-disc configuration under normal load of 5 N and at a sliding speed of 4 cm/s were used to study the friction and wear behavior of treated samples. Results show that the ferrite–martensite morphology has a great influence on the mechanical properties of dual phase steel. The steel subjected to (IQ) treatment attain superior mechanical properties compared to the SQ and the DQ treatments. On the other hand, it is also found that the friction coefficient and the wear rate (volume loss) decrease when the hardness and the martensite volume fraction increase. The steel with fine fibrous martensite provide good wear resistance.


Author(s):  
A. K. Rana ◽  
P. P. Dey

In this work, the von Mises stress and plastic strain distribution of Ferrite-Martensite–Dual-Phase (FMDP) steels are predicted at various stages of deformation. The failure modes and volume fraction effect are identified based on Representative Volume Element (RVE). FMDP steel consists of a typical ferrite-matrix phase, in which martensite-islands are dispersed. Recently FMDP steels are increasingly used to the various car parts in demand. 2D-RVEs are also utilised to predict the orientations effect of the martensite phase in the FMDP steels. Based on the position of the element, the boundary conditions (BC) are given in the RVE of FMDP steel microstructures. The failure modes are examined in the form of severe plastic strain localisation. While the distribution of islands in the microstructure varies, as a result, the deformation inhomogeneity increases with a rise of martensite fraction. The results of numerical computation and the trend of experimental failure shown in the literature are compared. This is signifying that the overall macro-behaviour of FMDP steel, as a consequence of stress-strain partitioning and influence of martensite-island volume fractions (MVFs), can be predicted by the finite element (FE) based 2D-RVE modelling.


Sign in / Sign up

Export Citation Format

Share Document