Hot Deformation Behavior and Microstructure of U720Li Alloy

2013 ◽  
Vol 709 ◽  
pp. 143-147 ◽  
Author(s):  
Tao Wang ◽  
Zhao Li ◽  
Shu Hong Fu ◽  
Yong Zhang ◽  
Yu Xin Zhao ◽  
...  
Keyword(s):  
Grain Size ◽  
Flow Stress ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Primary Phase ◽  
Compression Tests ◽  
Hot Deformation Behavior ◽  
Fine Grain ◽  
Lower Strain

The hot deformation behavior of U720Li was investigated by isothermal compression tests at temperature ranging from 1060-1180°C and strain rate from 0.001s-1 to 20s-1. The flow stress-strain curves and microstructures were investigated and a constitutive equation was established. It is found that flow stress is sensitive to stain rate and deformation temperature greatly. The higher stain rate resultes in a larger fluctuation in flow stress. The hot deformation activation energy is determined to be 552.8kJ/mol. Grain size increases with increasing temperature and decreases firstly and then increases with increasing strain rate. U720Li alloy should be deformed below the solve temperature of γ primary phase with lower strain rate in order to obtain the even and fine grain size.

scholarly journals Hot deformation behavior of TC18 titanium alloy

2013 ◽  
Vol 17 (5) ◽  
pp. 1523-1528
Author(s):  
Bao-Hua Jia ◽  
Wei-Dong Song ◽  
Hui-Ping Tang ◽  
Jian-Guo Ning
Keyword(s):  
Titanium Alloy ◽  
Flow Stress ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
True Strain ◽  
Testing Machine ◽  
Constitutive Relationship ◽  
Compression Tests ◽  
Hot Deformation Behavior

Isothermal compression tests of TC18 titanium alloy at the deformation temperatures ranging from 25?C to 800?C and strain rate ranging from 10-4 to 10-2 s-1 were conducted by using a WDW-300 electronic universal testing machine. The hot deformation behavior of TC18 was characterized based on an analysis of the true stress-true strain curves of TC18 titanium alloy. The curves show that the flow stress increases with increasing the strain rate and decreases with increasing the temperature, and the strain rate play an important role in the flow stress when increasing the temperatures. By taking the effect of strain into account, an improved constitutive relationship was proposed based on the Arrhenius equation. By comparison with the experimental results, the model prediction agreed well with the experimental data, which demonstrated the established constitutive relationship was reliable and can be used to predict the hot deformation behavior of TC18 titanium alloy.

scholarly journals Hot Deformation Behavior and Constitutive Analysis of As-Extruded Mg–6Zn–5Ca–3Ce Alloy Fabricated by Rapid Solidification

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 480
Author(s):  
Chengli Bao ◽  
Tao Zhou ◽  
Laixin Shi ◽  
Mingao Li ◽  
Li Hu ◽  
...  
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Rapid Solidification ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Dislocation Motion ◽  
Hot Deformation Behavior ◽  
Constitutive Analysis ◽  
Fine Grain ◽  
Hcp Structure

The plasticity of Mg–6Zn–5Ca–3Ce alloy fabricated by rapid solidification (RS) at room temperature is poor due to its hexagonal-close-packed (HCP) structure. Therefore, hot deformation of RS Mg–6Zn–5Ca–3Ce alloy at elevated temperature would be a major benefit for manufacturing products with complex shapes. In the present study, hot deformation behavior of as-extruded Mg–6Zn–5Ca–3Ce alloy fabricated by RS was investigated by an isothermal compression test at a temperature (T) of 573–673 K and strain rate (ε˙) of 0.0001–0.01 s−1. Results indicated that the flow stress increases along with the declining temperature and the rising strain rate. The flow stress behavior was then depicted by the hyperbolic sine constitutive equation where the value of activation energy (Q) was calculated to be 186.3 kJ/mol. This issue is mainly attributed to the existence of fine grain and numerous second phases, such as Mg2Ca and Mg–Zn–Ce phase (T’ phase), acting as barriers to restrict dislocation motion effectively. Furthermore, strain compensation was introduced to incorporate the effect of plastic strain on material constants (α,Q,n,lnA) and the predicted flow stresses under various conditions were roughly consistent with the experimental results. Moreover, the processing maps based on the Murty criterion were constructed and visualized to find out the optimal deformation conditions during hot working. The preferential hot deformation windows were identified as follows: T = 590–640 K, ε˙ = 0.0001–0.0003 s−1 and T = 650–670 K, ε˙ = 0.0003–0.004 s−1 for the studied material.

The effects of temperature and strain rate on the hot deformation behavior of AISI H10 tool steel

2020 ◽  
Vol 118 (1) ◽  
pp. 107
Author(s):  
Maryam Kamali Ardakani ◽  
Maryam Morakabati
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Tool Steel ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Strain Rates ◽  
Compression Tests ◽  
Hot Deformation Behavior ◽  
Temperature Range

The hot deformation behavior of a H10 hot work tool steel was studied by performing hot compression tests over the temperature range of 900 to 1200 °C and strain rates of 0.001–1 s−1 and total strain of 0.7. At temperatures below 1100 °C, the grain size is fine and below 20 μm. In this temperature range, grain size increase with temperature due to dissolution of carbides. Then by increasing temperature to 1150 and 1200 °C, the grain size is increased significantly due to growth of grains. The study on the effect of strain rate showed that at constant temperature of 1000 °C, the grain size increased from 4.8 to 6 μm with increasing strain rate from 0.001 to 1 s−1. Also, this increase in the strain rate at temperature of 1100 °C lead to increase the grain size from 5.9 to 17 μm, due to the occurrence of dynamic recrystallization. At 1200 °C growth of grains causes to decrease grain size from 112 to 87 μm by increasing strain rate. According to the microstructural investigations, at the temperatures of 1000 and 1100 °C and strain rates of 0.01 and 0.1 s−1 dynamic recrystallization was the main softening mechanism. As a result, the most suitable range for hot deformation was obtained at the temperature range of 1000–1100 °C and strain rates of 0.01–0.1 s−1.

scholarly journals Hot Deformation Behavior and Microstructure Evolution of a TiBw/Near α-Ti Composite with Fine Matrix Microstructure

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 481 ◽  
Author(s):  
Zhang ◽  
Lian ◽  
Chen ◽  
Sun ◽  
Zhang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Flow Stress ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Microstructure Evolution ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Compression Tests ◽  
Hot Deformation Behavior ◽  
Matrix Microstructure

The hot deformation behavior and microstructure evolution of a 7.5 vol% TiBw/near α-Ti composite with fine matrix microstructure were investigated under the deformation conditions in a temperature range of 800–950 °C and strain rate range of 0.001–1 s−1 using plane strain compression tests. The flow stress curves show different characteristics according to the various deformation conditions. At a higher strain rate (1 s−1), the flow stress of the composite continuously increases until a peak value is reached. The activation energy is 410.40 kJ/mol, much lower than the activation energy of as-sintered or as-forged composites. The decreased activation energy is ascribed to the breaking of the TiBw reinforcement during the multi-directional forging and the resultant fine matrix microstructure. Refined reinforcement and refined matrix microstructure significantly improve the hot deformation ability of the composite. The deformation conditions determine the morphology and fraction of α and β phases. At 800–900 °C and 0.01 s−1 the matrix α grains are much refined due to the continuous dynamic recrystallization (CDRX). The processing map is constructed based on the hot deformation behavior and microstructure evolution. The optimal hot processing window is determined to be 800–950 °C/0.001–0.01 s−1, which lead to CDRX of primary α grains or dynamic recovery (DRV) and dynamic recrystallization (DRX) of β phase.

Influence of Thermomechanical Parameters on the Hot Deformation Behavior of AA1070

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
H. R. Rezaei Ashtiani ◽  
H. Bisadi ◽  
M. H. Parsa
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Constitutive Equations ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Pure Aluminum ◽  
Engineering Practice ◽  
Compression Tests ◽  
Hot Deformation Behavior ◽  
Wide Range

The experimental stress–strain data from isothermal hot compression tests, in a wide range of temperatures (350–500 °C) and strain rates (0.005–0.5 s−1), were employed to develop constitutive equations in a commercially pure aluminum (AA1070). The effects of temperature and strain rate on the hot deformation behavior were represented by Zener–Hollomon parameter including Arrhenius term. The results show that the hardening rate and flow stress are evidently affected by both deformation temperature and strain rate. The power law, exponential, and hyperbolic sinusoidal types of Zener–Hollomon equations were used to determine the hot deformation behavior of AA1070. The results suggested that the highest correlation coefficient was achieved for the hyperbolic sine law for the studied material. So the proposed deformation constitutive equations can give an accurate and precise estimate of the flow stress for AA1070, which means it can be used for numerical simulation of hot forming processes and for choosing proper forming parameters in engineering practice accurately.

Effects of Original Microstructure on Hot Deformation Behavior and Microstructure of a P/M Ni-Base Superalloy

2019 ◽  
Vol 960 ◽  
pp. 78-84 ◽  
Author(s):  
Chao Yuan Wang ◽  
Xiao Jun Song ◽  
Jin Wen Zou
Keyword(s):  
Steady State ◽  
Flow Stress ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Isothermal Compression ◽  
Compression Tests ◽  
Hot Deformation Behavior ◽  
Base Superalloy ◽  
Grain Diameter

The hot deformation behavior and microstructure of a powder metallurgy (P/M) Ni-base superalloy with different original microstructure were studied by isothermal compression tests. The isothermal compression tests were conducted on Gleeble-3500D simulator with the temperature range of 1000°C~1100°C and the strain rate of 0.001s-1~0.1s-1. The results showed that the flow stress of the specimens with fine grains (10μm) and ultrafine grains (3μm) gained by hot extruding (HEX) were much less than the that with the average grain diameter of 30μm by hot isostatic pressing (HIP). At the strain rate of 0.001s-1，the as-HIPed specimens with the average grain diameter of 30μm showed steady-state deformation at 1100°C only， whereas the as-HEXed specimens with the average grain diameter of 10μm and 3μm showed steady-state deformation both at 1050°C and 1100°C. The flow stress showed decreasing trend as the average grain diameter decreasing. The activation energy of hot deformation decreased form 622.79 kJ·mol-1 to 302.36 kJ·mol-1 as the average grain diameter decreased from 30μm to 3μm. When the as-HEXed specimen with the average grain diameter of 3μm was deformed at the condition of (1050°C, 0.001s-1), the flow stress was lower than that at the condition of (1100°C,0.001s-1), and the former also gained much finer and uniform grain, the later gained mixed grains.

Modeling the Hot Deformation Behavior of 1565ch Aluminum Alloy

2016 ◽  
Vol 684 ◽  
pp. 35-41 ◽  
Author(s):  
S.V. Rushchits ◽  
E.V. Aryshensky ◽  
S.M. Sosedkov ◽  
A.M. Akhmed'yanov
Keyword(s):  
Aluminum Alloy ◽  
Flow Stress ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Static Recrystallization ◽  
Strain Rates ◽  
Strain Resistance ◽  
Hot Deformation Behavior ◽  
Zirconium Addition

The deformation behavior of 1565ch alloy under the plane-strain conditions in the temperature range of 350–490 оС and strain rates range of 0,1–10 s-1 is studied. The expression for steady flow stress as the functions of temperature of deformation and strain rate is obtained. It is established that 1565ch alloy with zirconium addition shows higher strain resistance and less tendency to dynamic and static recrystallization than AMg6.

scholarly journals Hot deformation behavior of 60NiTi shape-memory alloy fabricated by hot isostatic pressing

2022 ◽  
Author(s):  
Mei-ling Li ◽  
Wen-jin Gao ◽  
Ying-hao Zhou
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Work Hardening ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Dynamic Equilibrium ◽  
High Stress ◽  
Cylindrical Sample ◽  
Hot Working ◽  
Hot Deformation Behavior

Abstract The 60NiTi (Ni60wt%–Ti40wt%) intermetallic is a hard-to-process material. Understanding of hot deformation behavior is crucial for the hot working of 60NiTi. This work studied hot deformation behavior and corresponding microstructure of the hot isostatic pressed 60NiTi in the temperature range of 900 °C–1050 °C and at strain rates of 0.1, 0.01, and 0.001 s-1 through a hot compression test. The flow stress and microstructure were susceptible to the hot deformation parameters. The flow stress decreased with the increase in deformation temperature and decrease in strain rate. Work hardening occurred at a small strain, then followed by softening; finally, near-dynamic equilibrium was achieved between work hardening and softening. A constitutive equation was developed to describe the effects of strain rate and temperature on flow stress. Simulation of hot deformation via the finite element method revealed the workpiece’s inhomogeneous deformation. The deformation occurred mainly in the center area of the cylindrical sample, resulting in high stress and strain concentrations in this region and causing the equiaxial grains to be compressed into prolate grains. This work can provide guidance for the hot working, such as forging and hot rolling, of 60NiTi.

Hot Deformation Behavior of Multi-Size Al2O3 Particles Dispersion Strengthened Copper Base Composite

2013 ◽  
Vol 721 ◽  
pp. 270-273
Author(s):  
Xue Rui Yang ◽  
Bao Hong Tian ◽  
Yi Zhang ◽  
Yong Liu
Keyword(s):  
Flow Stress ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Compression Tests ◽  
Hot Deformation Behavior ◽  
Copper Base ◽  
Softening Mechanism ◽  
Deformation Activation Energy ◽  
Base Composite ◽  
Hot Press Sintering

The multi-size Al2O3 particles dispersion strengthened copper base composite (i.e. Al2O3/Cu-0.6%Al2O3 composite) was prepared by the vacuum hot-press sintering-internal oxidizing method. The hot deformation behavior of Al2O3/Cu-0.6%Al2O3 composite was investigated by the isothermal compression tests at the temperature range from 600°C to 950°C and strain rates of 0.001 s-1 and 1s-1 respectively with a Gleeble-1500D thermal simulator system. The results show that the flow stress-strain curves of Al2O3/Cu-0.6%Al2O3 composites indicate the softening mechanism of recrystallization. The flow stress increases with the deformation strain increasing, then decreases and tends to be steady. The hot deformation activation energy is calculated as 116.46 kJ/mol for the Al2O3/Cu-0.6%Al2O3 composite. The strain-stress constitutive equation is established on the basis of above results.

Artificial Neural Network to Predict the Hot Deformation Behavior of Super 13Cr Martensitic Stainless Steel

2011 ◽  
Vol 695 ◽  
pp. 361-364 ◽  
Author(s):  
Ying Han ◽  
Guan Jun Qiao ◽  
Dong Na Yan ◽  
De Ning Zou
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Stainless Steel ◽  
Flow Stress ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Martensitic Stainless Steel ◽  
Ann Model ◽  
Hot Deformation Behavior

The hot deformation behavior of super 13Cr martensitic stainless steel was investigated using artificial neural network (ANN). Hot compression tests were carried out at the temperature range of 950°C to 1200°C and strain rate range of 0.1–50s–1at an interval of an order of magnitude. Based on the limited experimental data, the ANN model for the constitutive relationship existed between flow stress and strain, strain rate and deformation temperature was developed by back-propagation (BP) neural network method. A three layer structured network with one hidden layer and ten hidden neurons was trained and the normalization method was employed in training for avoiding over fitting. Modeling results show that the developed ANN model can efficiently predict the flow stress of the steel and reflect the hot deformation behavior in the whole deforming process.

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