scholarly journals Hot Deformation Characteristics—Constitutive Equation and Processing Maps—of 21-4N Heat-Resistant Steel

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 89 ◽  
Author(s):  
Yiming Li ◽  
Hongchao Ji ◽  
Wangda Li ◽  
Yaogang Li ◽  
Weichi Pei ◽  
...  
Keyword(s):  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
Strain Rate Range ◽  
Processing Maps ◽  
Resistant Steel ◽  
Heat Resistant Steel ◽  
Rate Range ◽  
Temperature Range ◽  
Heat Resistant

Abstract: The hot deformation behavior of 21-4N heat-resistant steel was studied by hot compression test in a deformation temperature range of 1000–1180 °C, a strain rate range of 0.01–10 s−1 and a deformation degree of 60%, and the stress-strain curves were obtained. The functional relationship between flow stress and process parameters (deformation degree, deformation temperature, strain rate, etc.) of 21-4N heat-resistant steel during hot deformation was explored, the constitutive equation of peak stress was established, and its accuracy was verified. Based on the dynamic material model, the energy dissipation maps and destabilization maps of 21-4N heat-resistant steel were established at strains of 0.2, 0.4 and 0.6, and processing maps were obtained by their superposition. Within the deformation temperature range of 1060~1120°C and a strain rate range of 0.01–0.1 s−1, there is a stable domain with the peak efficiency of about 0.5. The best hot working parameters (strain rate and deformation temperature) of 21-4N heat-resistant steel are determined by the stable and instable domain in the processing maps, which are in the deformation temperature range of 1120–1180 °C and the strain rate range of 0.01–10 s−1.

Characterization of Hot Deformation Behavior of Zr-4 Alloy in Material Application Area

2012 ◽  
Vol 578 ◽  
pp. 202-205
Author(s):  
Guo Qing Lin
Keyword(s):  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Flow Behavior ◽  
Strain Rate Range ◽  
Processing Maps ◽  
Peak Efficiency ◽  
Hot Deformation Behavior ◽  
Rate Range ◽  
Temperature Range

The hot deformation behavior of Zr-4 alloy was studied in the temperature range 650-900°C and strain rate range 0.005-50s-1 using processing maps. The processing maps revealed three domains: the first occurs in the temperature range 780-820°C and strain rate range 0.005-0.05s-1, and has a peak efficiency of 45% at 790°C and 0.005s-1; the mechanism is the dynamic recrystallization. The second occurs in the temperature range greater than 900°C and strain rate range 0.05-0.8s-1, and has a peak efficiency of 40% at 900°C and 0.5s-1, which are the domains of dynamic recovery. In addition, the instability zones of flow behavior can also be recognized by the maps in the temperature range 650-780°C and strain rate range 0.01-0.1s-1, which should be strictly avoided in the processing of the material. Zr-4 alloy is the material for pressure tube applications in nuclear reactors and has better strength and a lower rate of hydrogen uptake compared to other materials under similar service conditions.

Hot Deformation Behavior and Processing Map of 25%SiCp/2009A1 Composite

2016 ◽  
Vol 849 ◽  
pp. 409-415 ◽  
Author(s):  
Shao Hua Wei ◽  
Yan Qiang Liu ◽  
Jun Hui Nie ◽  
Tao Zuo ◽  
Zi Li Ma ◽  
...  
Keyword(s):  
Strain Rate ◽  
Hot Deformation ◽  
Constant Strain Rate ◽  
Material Model ◽  
Strain Rate Range ◽  
Deformation Condition ◽  
Processing Maps ◽  
Rate Range ◽  
Temperature Range ◽  
Dynamic Material Model

The hot deformation characteristics of 25%SiCp/2009A1 composite fabricated by powder metallurgy route were studied by thermal compaction testing on Gleeble-3800 hot-simulation machine in the temperature range of 370~520 °C and strain rate range of 0.01~10 s-1. The processing maps of 25%SiCp/2009A1 composites were developed on the basis of dynamic material model. The results show that the flow stress decreased with increasing deformation temperature at a constant strain rate, and increased with increasing strain rate at a constant temperature. The processing maps present unsteady zones at high strain rate (≥1 s-1). There are a few interfaces of particle-matrix separated and the particle itself cracked. There was significant dynamic recovery and dynamic recrystallization occurred in the higher temperature and lower strain rate region. The optimum hot deformation condition of the composites attained by the maps were in the temperature range of 450~490 °Cand in the strain rate range of 0.01~0.1 s-1.

Flow Behavior and Workability of a Zn-8Cu-0.2Cr Alloy during Hot Deformation

2012 ◽  
Vol 538-541 ◽  
pp. 1257-1261
Author(s):  
Sheng Li Guo ◽  
Peng Du ◽  
Xiao Ping Wu ◽  
De Fu Li
Keyword(s):  
Constitutive Equation ◽  
Strain Rate ◽  
Hot Deformation ◽  
Flow Instability ◽  
Flow Behavior ◽  
Strain Rate Range ◽  
Processing Maps ◽  
Compression Tests ◽  
Rate Range ◽  
Temperature Range

The hot deformation behavior of Zn91.8-Cu8-Cr0.2 (in wt.%) was investigated by means of hot compression tests in the temperature range of 230-380 °C and strain rate range of 0.01 - 10 s-1. The constitutive equation and processing maps were developed. The influence of strain on the flow stress was studied by considering the effect of the strain on material constants. The stress-strain curves obtained by the constitutive equation are in good agreement with experimental results. The proposed constitutive equations can be used for the analysis problem of hot forming processes. The processing maps have exhibited a domain, which is optimum processing window for hot working, in the temperature range of 310 - 380 °C and strain rate range of 0.01-1 s-1 corresponding to the higher efficiency of power dissipation. The large regime of flow instability is observed at high strain rate. The instability regime should be avoided during hot deformation processing.

Influences of Strain Rate and Deformation Temperature on Flow Stress and Dynamic Recrystalliazation of Heat Resistant Steel P91

2011 ◽  
Vol 217-218 ◽  
pp. 958-963
Author(s):  
Xue Qin Jin ◽  
Da Sen Bi ◽  
Jian Zhang ◽  
Xiao Lan Wang ◽  
Jian Hua Song ◽  
...  
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Strain Curve ◽  
Strain Rate Range ◽  
Thick Wall ◽  
Resistant Steel ◽  
Heat Resistant Steel ◽  
Heat Resistant

In power station big caliber thick wall seamless tube typical steel P91for example, The hot deformation behavior and heat flow stress-strain curve of the heat resistant steel P91was investigated with a compression test on Gleeble3500 simulator at a temperature range of 1050°C～1200°C and strain rate range of 10-4～5s-1. The test curve shows that P91 materials have the dynamic recrystallization and recovery behavior in high temperature and deformation. With the rise of temperature and strain rate of decreased, flow stress is lower and the dynamic recrystallization phenomenon is easier to occur. By metalloscope observed, in the high temperature and low strain rate conditions, the dynamic recrystallization area and new nucleation grain size are larger, and microstructure is more uniformly distributed.

A Study at the Workability of Ultra-High Strength Steel Sheet by Processing Maps on the Basis of DMM

2017 ◽  
Vol 36 (7) ◽  
pp. 657-667 ◽  
Author(s):  
Yu Feng Xia ◽  
Shuai Long ◽  
Tian-Yu Wang ◽  
Jia Zhao
Keyword(s):  
Activation Energy ◽  
Strain Rate ◽  
High Strength Steel ◽  
High Strength ◽  
Strain Rate Range ◽  
Diffusion Activation Energy ◽  
Processing Maps ◽  
Rate Range ◽  
Temperature Range ◽  
Ultra High Strength Steel

AbstractThe hot workability of the ultra-high strength steel BR1500HS has been investigated by processing maps. A series of hot deformation tensile tests were carried out on a Gleeble-3500 thermal simulator in the deformation temperature range of 773–1,223 K and strain rate range of 0.01–10 s–1. The obtained flow stress curves reveal that the peak stress increases with the rising of strain rate and decreases with the rising of temperature. Based on dynamic materials model (DMM), the processing maps at the strains of 0.05, 0.10 and 0.15 were developed, and the optimum hot working conditions were recommended as the temperature range of 1,200–1,223 K and the strain rate range of 0.01–0.1 s–1, where the peak power dissipation efficiency is about 37 % revealing the occurrence of typical dynamic recrystallization (DRX). The main instability defects are deformation twinning and micro-crack occurring mainly at the temperature range of 773–873 K with the strain rate higher than 1 s–1. In order to deeply understand the microstructure mechanisms, the Zener–Hollomon parameter is solved, and then the self-diffusion activation energy is compared with the apparent activation energy Q at different deformation temperatures and strain rates.

Hot Deformation Behavior and Processing Maps of 7050 Aluminum Alloy

2013 ◽  
Vol 815 ◽  
pp. 37-42 ◽  
Author(s):  
Yu Juan Guo ◽  
Lei Deng ◽  
Xin Yun Wang ◽  
Jun Song Jin ◽  
Wen Wu Zhou
Keyword(s):  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Strain Rate Range ◽  
Processing Maps ◽  
Compression Tests ◽  
Hot Deformation Behavior ◽  
Temperature Range ◽  
Optimal Processing ◽  
Working Region

The hot deformation behavior of 7050aluminum alloy was investigated by hot compression tests in the temperature range of 573-773K and the strain rate ranging from 0.001s-1to 10 s-1.The flow curves showed that the flow stresses increase with the increase of strain rate or the decrease of temperature.In order to determine the optimal processing conditions, hot processing maps were established based on experimental data and Dynamic Materials Model. The processing maps indicate that instability occur at low temperature and high strain rate. The optimum hot working region is the domain in the temperature range of 673-723K and strain rate range of 0.001-0.01 s-1,where typical recrystallization was observed in the optical microstructures.

Processing Maps for TC18 Titanium Alloy Deformed in α+β Region

2012 ◽  
Vol 490-495 ◽  
pp. 3423-3426 ◽  
Author(s):  
Xin Zhao ◽  
Hong Zhao ◽  
Rui Zhang
Keyword(s):  
Titanium Alloy ◽  
Strain Rate ◽  
Power Dissipation ◽  
Strain Rate Range ◽  
Hot Working ◽  
Maximum Efficiency ◽  
Processing Maps ◽  
Compression Tests ◽  
Rate Range ◽  
Temperature Range

The hot deformation characteristics of TC18 titanium alloy were studied in the temperature range 750-850°C and strain rate range 0.001-1 s-1 by using hot compression tests. Processing maps for hot working are developed on the basis of the variations of efficiency of power dissipation with temperature and strain rate. The results reveal that the flow stress of TC18 is sensitive to strain rate. Processing map at stain of 0.6 reveals two domains: one is centered at 750°C and 0.001s-1; another is centered at 850°C and 0.001s-1. The maximum efficiency is more than 60%. According to the maps, the zone with the temperature range of 750-850°C and strain rate range of 0.01-0.001s-1 may be suitable for hot working

scholarly journals Hot Deformation Behavior of Homogenized Mg-13.5Gd-3.2Y-2.3Zn-0.5Zr Alloy via Hot Compression Tests

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2282 ◽  
Author(s):  
Zhimin Zhang ◽  
Zhaoming Yan ◽  
Yue Du ◽  
Guanshi Zhang ◽  
Jiaxuan Zhu ◽  
...  
Keyword(s):  
Low Temperature ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Hot Deformation ◽  
Strain Rate Range ◽  
Hot Compression ◽  
Test Machine ◽  
Compression Tests ◽  
Rate Range ◽  
Temperature Range

Mg-Gd-Y-Zn-Zr Mg alloys show excellent performance in high-end manufacturing due to its strength, hardness and corrosion resistance. However, the hot deformation and dynamic recrystallization (DRX) behaviors of Mg-13.5Gd-3.2Y-2.3Zn-0.5Zr were not studied. For this article, hot compression behavior of homogenized high rare-earth (RE) content Mg-13.5Gd-3.2Y-2.3Zn-0.5Zr (wt%) alloy was investigated by using the Gleeble-3500D thermo-simulation test machine under the temperature of 350–500 °C and the strain rate of 0.001–1 s−1. It was found that the high flow stress corresponded to the low temperature and high strain rate, which showed DRX steady state curve during the hot compression. The hot deformation average activation was 263.17 kJ/mol, which was obtained by the analysis of the hyperbolic constitutive equation and the Zener-Hollomon parameter. From observation of the microstructure, it was found that kink deformation of long period stacking ordered (LPSO) phase was one of the important coordination mechanisms of hot deformation at low temperature. The processing map with the strain of 0.5 was established under the basis of dynamic material model (DMM); it described two high power dissipation domains: one appearing in the temperature range of 370–440 °C and the strain rate range of 0.001–0.006 s−1, the other appearing in the temperature range of 465–500 °C and strain rate range of 0.001–0.05 s−1, in which dynamic recrystallization (DRX) mainly ocurred. The highest degree of DRX was 18% from the observation of the metallographic.

scholarly journals Superplasticity of Ti-6Al-4V Titanium Alloy: Microstructure Evolution and Constitutive Modelling

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1756 ◽  
Author(s):  
Ahmed O. Mosleh ◽  
Anastasia V. Mikhaylovskaya ◽  
Anton D. Kotov ◽  
James S. Kwame ◽  
Sergey A. Aksenov
Keyword(s):  
Strain Rate ◽  
Microstructural Evolution ◽  
Deformation Temperature ◽  
Superplastic Deformation ◽  
Deformation Behaviour ◽  
Strain Rate Range ◽  
Grain Structure ◽  
Rate Range ◽  
Temperature Range ◽  
Elongation To Failure

Determining a desirable strain rate-temperature range for superplasticity and elongation-to-failure are critical concerns during the prediction of superplastic forming processes in α + β titanium-based alloys. This paper studies the superplastic deformation behaviour and related microstructural evolution of conventionally processed sheets of Ti-6Al-4V alloy in a strain rate range of 10–5–10–2 s–1 and a temperature range of 750–900 °C. Thermo-Calc calculation and microstructural analysis of the as-annealed samples were done in order to determine the α/β ratio and the grain size of the phases prior to the superplastic deformation. The strain rate ranges, which corresponds to the superplastic behaviour with strain rate sensitivity index m ˃ 0.3, are identified by step-by-step decreasing strain rate tests for various temperatures. Results of the uniaxial isothermal tensile tests at a constant strain rate range of 3 × 10−4–3 × 10−3 s−1 and a temperature range of 800–900 °C are presented and discussed. The experimental stress-strain data are utilized to construct constitutive models, with the purpose of predicting the flow stress behaviour of this alloy. The cross-validation approach is used to examine the predictability of the constructed models. The models exhibit excellent approximation and predictability of the flow behaviour of the studied alloy. Strain-induced changes in the grain structure are investigated by scanning electron microscopy and electron backscattered diffraction. Particular attention is paid to the comparison between the deformation behaviour and the microstructural evolution at 825 °C and 875 °C. Maximum elongation-to-failure of 635% and low residual cavitation were observed after a strain of 1.8 at 1 × 10−3 s−1 and 825 °C. This temperature provides 23 ± 4% β phase and a highly stable grain structure of both phases. The optimum deformation temperature obtained for the studied alloy is 825 °C, which is considered a comparatively low deformation temperature for the studied Ti-6Al-4V alloy.

scholarly journals High Temperature Behaviors of a Casting Nickel-Based Superalloy Used for 815 °C

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 716
Author(s):  
Jiangping Yu ◽  
Donghong Wang ◽  
Jingyang Chen ◽  
Changlin Yang ◽  
Xin Hao ◽  
...  
Keyword(s):  
Strain Rate ◽  
Hot Deformation ◽  
Peak Stress ◽  
Strain Rate Range ◽  
Deformation Condition ◽  
Strain Rates ◽  
Rate Range ◽  
Temperature Range ◽  
Nickel Based Superalloy ◽  
Deformation Behaviors

The hot deformation behaviors of the SJTU-1 alloy, the high-throughput scanned casting Nickel-based superalloy, was investigated by compression test in the temperature range of 900 to 1200 °C and strain rate range of 0.1–0.001 s−1. The hot processing map has been constructed with the instability zone. At the beginning of hot deformation, the flow stress moves rapidly to the peak value with the increased strain rates. Meanwhile, the peak stress is decreased with the increased temperature at the same strain rates. However, the peak stress shows the same tendency with the strain rates at the same temperature. The optimum hot deformation condition was determined in the temperature range of 1000–1075 °C, and the strain rate range of 0.005–0.1 s−1. The microstructure investigation indicates the strain rate significantly affects the characteristics of the microstructure. The deformation constitutive equation has also been discussed as well.

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