scholarly journals Effect of Deformation Heating on Microstructure Evolution During Hot Forging of Ti-6Al-4V

2021 ◽  
Author(s):  
Mykola Kulakov ◽  
Salaheddin Rahimi ◽  
S. Lee Semiatin
Keyword(s):  
Microstructure Evolution ◽  
Volume Fraction ◽  
True Strain ◽  
Hot Forging ◽  
Solute Concentration ◽  
High Rate ◽  
Circular Cylinders ◽  
Deformation Heating ◽  
Heating And Cooling ◽  
High Rate Deformation

AbstractThe effect of deformation heating on microstructure evolution during hot forging of Ti-6Al-4V was established. For this purpose, right-circular cylinders of Ti-6Al-4V with an equiaxed-α preform microstructure were preheated to a temperature between 1148 K (875 °C) and 1223 K (950 °C), and compressed to a 60-pct. height reduction in a screw press, yielding average true strain rates of ~ 5 to 20 s−1. Thermocouple measurements and corroborating finite-element-method (FEM) simulations quantified substantial deformation-heating-induced temperature increases. For all preheat temperatures, the heating transient led to an exposure above the equilibriumβ transus temperature. Despite such temperature excursions, the volume fraction of equiaxed primary α in each forged billet was only slightly lower than that in the corresponding preheated condition. The source of such observations was rationalized on the basis of the (hypothesized) solute-concentration fields that develop during the heating and cooling transients experienced in high-rate deformation processing.

Simulation of Deformation Behavior and Microstructure Evolution during Hot Forging of TC11 Titanium Alloy

2018 ◽  
Vol 385 ◽  
pp. 449-454 ◽  
Author(s):  
Artem Alimov ◽  
Dmitry Zabelyan ◽  
Igor Burlakov ◽  
Igor Korotkov ◽  
Yuri Gladkov
Keyword(s):  
Titanium Alloy ◽  
Microstructure Evolution ◽  
Technology Development ◽  
Hot Forging ◽  
Industrial Case Study ◽  
Aerospace Applications ◽  
Heating And Cooling ◽  
Tc11 Titanium Alloy ◽  
Kinetics Of

Finite element method is the most powerful tool for development and optimization of the metal forming processes. Analysis of titanium alloy critical parts should include the prediction of microstructure since their mechanical and technological properties essentially depend on the type and parameters of the microstructure. The technological process of parts production for aerospace applications is multi-operational and consists of deformation, heating and cooling stages. Therefore, it is necessary to simulate the microstructure evolution to obtain high quality parts. In presented paper FE simulation coupled with microstructure evolution during hot forging of TC11 titanium alloy has been performed by QForm FEM code. Constitutive relationships, friction conditions and microstructure evolution model have been established using the experiments. The kinetics of phase transformations has been described by the Johnson-Mehl-Avrami-Kolmogorov (JMAK) phenomenological model. The approach is illustrated by industrial case study that proved its practical applicability and economic advantages for technology development of titanium alloy critical parts.

Effect of Different Strain on Microstructure Evolution of Medium Carbon Steel

2013 ◽  
Vol 652-654 ◽  
pp. 923-928 ◽  
Author(s):  
Peng Tian ◽  
Zhi Yong Zhong ◽  
Wei Jun Hui ◽  
Rui Guo Bai ◽  
Xing Li Zhang
Keyword(s):  
Carbon Steel ◽  
Microstructure Evolution ◽  
Simulation Experiment ◽  
Volume Fraction ◽  
True Strain ◽  
Medium Carbon Steel ◽  
Controlled Cooling ◽  
Medium Carbon ◽  
The Right ◽  
Equilibrium Content

Uniaxial hot compression simulation experiment at 700°C with different true strain was carried out to study the microstructure evolution of medium carbon steel, the predominant mechanism on the cementite softening has been explored, the experimental results show that the volume fraction of deformation induced ferrite (DIF) increased with increasing true strain and even exceeds the equilibrium content. With the increase of DIF, more and more carbon atoms congregated in the boundaries such as the interface of DIF and the interphase of DIF/deformation austenite. Carbon congregation provides the right carbon content and the optimized microstructure for divorced decomposition during the process of controlled cooling. Therefore spherical or rod-like cementite and degenerated pearlite can be obtained.

Microstructure Evolution in a 304-Type Austenitic Stainless Steel during Multidirectional Forging at Ambient Temperature

2014 ◽  
Vol 783-786 ◽  
pp. 831-836 ◽  
Author(s):  
Alla Kipelova ◽  
Marina Odnobokova ◽  
Andrey Belyakov ◽  
Rustam Kaibyshev
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Microstructure Evolution ◽  
Room Temperature ◽  
Volume Fraction ◽  
True Strain ◽  
Nanocrystalline Structure ◽  
Multidirectional Forging ◽  
Average Size ◽  
Structural Mechanisms

The formation of nanocrystalline structure in a 304-type austenitic stainless steel during multidirectional forging (MDF) at room temperature was investigated. Initial coarse austenite grains with an average size of 50 μm were refined to about 80 nm by martensitic transformation during MDF to a total true strain of 2 and remained unchanged upon further deformation up to a strain of 4. The volume fraction of martensite achieved ~0.9 after forging to a strain of 1.6. The MDF at room temperature was accompanied by a significant hardening of the 304-type steel. The microhardness and the flow stress increased during forging and approached their saturations on the levels of about 5 GPa and 1.7 GPa, respectively, after total true strain of 2. The structural mechanisms responsible for microstructure evolution during severe deformation are discussed.

Study on Dynamic Recrystallization Behavior in Deformed Austenite of 52100 Steel by Using JMAK-Model

2013 ◽  
Vol 275-277 ◽  
pp. 1833-1837
Author(s):  
Ke Lu Wang ◽  
Shi Qiang Lu ◽  
Xin Li ◽  
Xian Juan Dong
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Hot Deformation ◽  
Volume Fraction ◽  
True Strain ◽  
Strain And Strain Rate ◽  
Average Grain Size ◽  
Dynamic Recrystallization Behavior ◽  
Simulation And Experiment ◽  
Good Agreement

A Johnson-Mehl-Avrami-Kolmogorov (JMAK)-model was established for dynamic recrystallization in hot deformation process of 52100 steel. The effects of hot deformation temperature, true strain and strain rate on the microstructural evolution of the steel were physically studied by using Gleeble-1500 thermo-mechanical simulator and the experimental results were used for validation of the JMAK-model. Through simulation and experiment, it is found that the predicted results of DRX volume fraction, DRX grain size and average grain size are in good agreement with the experimental ones.

Effect of high rate deformation induced precipitation hardening on the failure of aluminium rivets

1989 ◽  
Vol 24 (2) ◽  
pp. 599-608 ◽  
Author(s):  
Vincent K. S. Choo ◽  
Per G. Reinhall ◽  
Saeid Ghassaei
Keyword(s):  
Precipitation Hardening ◽  
High Rate ◽  
High Rate Deformation

High-rate deformation and fracture of steel 09G2S

2014 ◽  
Vol 49 (6) ◽  
pp. 666-672 ◽  
Author(s):  
Vl. Vas. Balandin ◽  
Vl. Vl. Balandin ◽  
A. M. Bragov ◽  
L. A. Igumnov ◽  
A. Yu. Konstantinov ◽  
...  
Keyword(s):  
High Rate ◽  
Steel 09G2s ◽  
Deformation And Fracture ◽  
High Rate Deformation

scholarly journals Study of the Dynamic Recrystallization Process of the Inconel625 Alloy at a High Strain Rate

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 510 ◽  
Author(s):  
Zhi Jia ◽  
Zexi Gao ◽  
Jinjin Ji ◽  
Dexue Liu ◽  
Tingbiao Guo ◽  
...  
Keyword(s):  
Dynamic Recrystallization ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Volume Fraction ◽  
Electron Backscatter Diffraction ◽  
Texture Evolution ◽  
True Strain ◽  
Recrystallization Process ◽  
Compression Process

High-temperature compression and electron backscatter diffraction (EBSD) techniques were used in a systematic investigation of the dynamic recrystallization (DRX) behavior and texture evolution of the Inconel625 alloy. The true stress–true strain curves and the constitutive equation of Inconel625 were obtained at temperatures ranging from 900 to 1200 °C and strain rates of 10, 1, 0.1, and 0.01 s−1. The adiabatic heating effect was observed during the hot compression process. At a high strain rate, as the temperature increased, the grains initially refined and then grew, and the proportion of high-angle grain boundaries increased. The volume fraction of the dynamic recrystallization increased. Most of the grains were randomly distributed and the proportion of recrystallized texture components first increased and then decreased. Complete dynamic recrystallization occurred at 1100 °C, where the recrystallized volume fraction and the random distribution ratios of grains reached a maximum. This study indicated that the dynamic recrystallization mechanism of the Inconel625 alloy at a high strain rate included continuous dynamic recrystallization with subgrain merging and rotation, and discontinuous dynamic recrystallization with bulging grain boundary induced by twinning. The latter mechanism was less dominant.

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