Microstructure-Based FEM Modeling of Phase Transformation During Quenching of Large-Size Steel Forgings

2021 ◽  
Vol 52 (5) ◽  
pp. 1883-1900
Author(s):  
Yassine Bouissa ◽  
Muftah Zorgani ◽  
Davood Shahriari ◽  
Henri Champliaud ◽  
Jean-Benoit Morin ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Fem Modeling ◽  
Large Size

Residual Stress Analysis Considering Phase Transformation and Transformation Plasticity for Heat-Treated Large Size Shaft

2016 ◽  
Vol 725 ◽  
pp. 647-652 ◽  
Author(s):  
Yusuke Yanagisawa ◽  
Yasuhiro Kishi ◽  
Katsuhiko Sasaki
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Phase Transformation ◽  
Air Cooling ◽  
Water Cooling ◽  
Stress Distributions ◽  
Transformation Plasticity ◽  
Large Size ◽  
Heat Treated ◽  
Good Agreement

The residual stress distributions of the forgings after both water-cooling and air-cooling were measured experimentally. The residual stress occurring during the heat-treatment was also simulated considering the phase transformation and the transformation plasticity. A comparison of the experiments with the simulations showed a good agreement. These results shows that the transformation plastic strain plays an important role in the heat treatment of large forged shafts.

scholarly journals Formation of Large Size Precipitate-Free Zones in β Annealing of the Near-β Ti-55531 Titanium Alloy

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 544 ◽  
Author(s):  
Xueqi Jiang ◽  
Xiaoqiang Shi ◽  
Xiaoguang Fan ◽  
Qi Li
Keyword(s):  
Titanium Alloy ◽  
Phase Transformation ◽  
Heterogeneous Nucleation ◽  
Isothermal Heat Treatment ◽  
Precipitate Free Zone ◽  
Mode Iii ◽  
Slow Cooling ◽  
Free Zone ◽  
Large Size ◽  
Α Phase

Large size (>10000 μm2) precipitate-free zones in the absence of microsegregation were observed in the near-β Ti-55531 titanium alloy after furnace cooling from high temperature and longtime annealing in the single-β phase field. To reveal the formation mechanism of the large size precipitate-free zone, continuous cooling and isothermal heat treatment were carried out to investigate the β-α phase transformation process. It was found that the large size precipitate free zone is attributed to the heterogeneous nucleation of α phase. The nucleation site evolves in three different modes: I-random nucleation inside the β grain, II-network nucleation inside the β grain and, III-heterogeneous nucleation on the precipitated α phase. Modes I and II lead to homogeneous transformed structure while Mode III results in the large size precipitate-free zone. Both modes II and III are promoted at high annealing temperature, rapid cooling above 600 °C or slow cooling below 600 °C. Mode II is common as it can minimize the strain energy in phase transformation. As a result, the formation of the large size precipitate-free zone is not deterministic.

FEM modeling and experimental validation of quench-induced distortions of large size steel forgings

2020 ◽  
Vol 58 ◽  
pp. 592-605 ◽  
Author(s):  
Y. Bouissa ◽  
N. Bohlooli ◽  
D. Shahriari ◽  
H. Champliaud ◽  
J-B. Morin ◽  
...  
Keyword(s):  
Experimental Validation ◽  
Fem Modeling ◽  
Large Size

Different Relaxation Modes of Epitaxial Thin Film Alloys With A Large Size Effect

1999 ◽  
Vol 578 ◽  
Author(s):  
J. Thibault ◽  
C. Dressler ◽  
P. Bayle-Guillemaud
Keyword(s):  
Thin Film ◽  
Phase Transformation ◽  
Stress Relaxation ◽  
Size Effect ◽  
Driving Force ◽  
Epitaxial Thin Film ◽  
Large Size ◽  
Relaxation Modes ◽  
Large Size Effect ◽  
Strong Size Effect

AbstractIn epitaxial layers, the mechanism of stress relaxation under consideration is in general dislocations. This paper will present experimental evidences for other modes of relaxation. which may occur in some situations especially where a strong size effect or misfit is present. In fact the stress is the driving force for intermixing, twinning, and phase transformation, which are not expected to occur in the bulk. All these experimental results have been sustained by numerical simulations that will also be presented.

Double Annealing Processes of Ti-5Al-5Mo-5V-1Cr-1Fe Titanium Alloy

2019 ◽  
Vol 944 ◽  
pp. 33-37
Author(s):  
Qing Rui Wang ◽  
Ai Xue Sha ◽  
Li Jun Huang ◽  
Xing Wu Li ◽  
Guang Bao Mi
Keyword(s):  
Mechanical Property ◽  
Titanium Alloy ◽  
Phase Transformation ◽  
Grain Boundary ◽  
Annealing Temperature ◽  
Small Deformation ◽  
Annealing Process ◽  
Air Cooling ◽  
Large Size ◽  
Comprehensive Property

In this work, double annealing processes of Ti-5Al-5Mo-5V-1Cr-1Fe titanium alloy were systemically investigated, and the microstructure and property of different processes were compared. The results show that, when the first stage annealing is air cooling, the microstructure with continuous and straight grain boundary is obtained, and corresponding mechanical property is not very good; When the first stage annealing is furnace cooling, the influence of first stage annealing temperature on microstructure and property is obvious. Excellent comprehensive property can be obtained when β grain boundary and a phase are discontinuous and tortuous. Further, based on this research, a new double annealing process is developed, which can obtain excellent ductility when large size forging is fabricated above the phase transformation point and has small deformation.

Influence of the Quench Process on Microstructure Evolution in a Landing Gear Steel

2014 ◽  
Author(s):  
Samir Mourad Chentouf ◽  
Mohammad Jahazi ◽  
Rejean Fortin
Keyword(s):  
Phase Transformation ◽  
High Resolution ◽  
Cooling Rate ◽  
Microstructure Evolution ◽  
Retained Austenite ◽  
Micro Hardness ◽  
Large Size ◽  
300M Steel ◽  
Gear Steel ◽  
Vickers Micro Hardness

The quench process of large size components is always problematic owing to non-uniform phase formation. In this context, the influence of cooling rate on phase transformation, for different cooling rates, in 300M steel is studied. A combination of high resolution dilatometry, optical microscopy, Vickers micro hardness measurements were employed to accurately determine the critical transformation temperature, and to identify microstructure constituents (bainite, martensite, and retained austenite). A mixture of bainite, martensite and some retained austenite phases were observed to appear at cooling rate of 0.25°C/sec whereas for a cooling rate of 50°C/sec the microstructure is totally martensitic.

Coherency loss in γ' precipitates in nickel-base superalloy

1983 ◽  
Vol 41 ◽  
pp. 244-245
Author(s):  
R. A. Ricks ◽  
Angus J. Porter
Keyword(s):  
Lattice Mismatch ◽  
Lattice Parameter ◽  
Nickel Base Superalloy ◽  
Large Size ◽  
The Matrix ◽  
Nimonic 80A ◽  
Interfacial Dislocations ◽  
Nickel Base ◽  
Coherency Loss ◽  
Nimonic 115

During a recent investigation concerning the growth of γ' precipitates in nickel-base superalloys it was observed that the sign of the lattice mismatch between the coherent particles and the matrix (γ) was important in determining the ease with which matrix dislocations could be incorporated into the interface to relieve coherency strains. Thus alloys with a negative misfit (ie. the γ' lattice parameter was smaller than the matrix) could lose coherency easily and γ/γ' interfaces would exhibit regularly spaced networks of dislocations, as shown in figure 1 for the case of Nimonic 115 (misfit = -0.15%). In contrast, γ' particles in alloys with a positive misfit could grow to a large size and not show any such dislocation arrangements in the interface, thus indicating that coherency had not been lost. Figure 2 depicts a large γ' precipitate in Nimonic 80A (misfit = +0.32%) showing few interfacial dislocations.

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