Hot Simulation Compression of In Situ TiBw/Ti6Al4V Composites with Novel Network Microstructure

2013 ◽  
Vol 762 ◽  
pp. 382-386
Author(s):  
Lu Jun Huang ◽  
Yu Zi Zhang ◽  
Lin Geng

The hot compression behavior of in situ TiB whiskers reinforced Ti6Al4V (TiBw/Ti6Al4V) composites with a novel network microstructure is investigated in the temperature range of 900-1100°C and strain rate range of 0.001-10 s-1. The results show that all the stress-strain curves of the composites display peak flow, softening and steady-state. Moreover, the peak flow stress decreases with increasing temperatures and decreasing strain rates. Processing map of the composite is constructed using the dynamic material model (DMM). Dynamic recrystallization (DRX) of α phase is observed in the deformation region corresponding with peak efficiency of the processing map. However, the flow instability region ranged from 900 to 1100°C at strain rates higher than 1.0 s-1should be avoided.

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4118
Author(s):  
Xuewen Chen ◽  
Yuqing Du ◽  
Tingting Lian ◽  
Kexue Du ◽  
Tao Huang

As a new-type of ultra-supercritical HI-IP rotor steel, X12CrMoWVNbN10-1-1 alloy steel has excellent integrative performance, which can effectively improve the power generation efficiency of the generator set. In this paper, uniaxial thermal compression tests were carried out over a temperature range of 950–1200 °C and strain rates of 0.05–5 s−1 with a Gleeble-1500D thermal simulation testing machine. Moreover, based on hot compression experimental data and the theory of processing diagrams, in combination with the dynamic material model, a three-dimensional (3-D) thermal processing map considering the effect of strain was constructed. It was concluded that optimum thermal deformation conditions were as follows: the temperature range of 1150–1200 °C, the strain rate range of 0.05–0.634 s−1. Through secondary development of the finite element (FE) software FORGE®, three-dimensional thermal processing map data were integrated into finite element software FORGE®. The distributions of instability coefficient and power dissipation coefficient were obtained over various strain rates and temperatures of the Ø 8 × 12 mm cylinder specimen by using finite element simulation. It is shown that simulation results are consistent with the microstructure photos. The method proposed in this paper, which integrates the three-dimensional processing map into the finite element software FORGE® (Forge NxT 2.1, Transvalor, Nice, France), can effectively predict the formability of X12CrMoWVNbN10-1-1 alloy steel.


2009 ◽  
Vol 610-613 ◽  
pp. 815-821 ◽  
Author(s):  
Xin Zhao ◽  
Kui Zhang ◽  
Xing Gang Li ◽  
Yong Jun Li ◽  
Kang Zhang ◽  
...  

The characteristic of dynamic recrystallization (DRX) in Mg-Y-Nd-Gd-Zr magnesium alloy had been investigated by compression test at temperatures between 523 and 723K and the strain rates ranging from 0.002 to 1s-1with maximum strain of 0.693. The flow behavior was described by a power exponent function. Processing map of this alloy was established on the basis of dynamic material model. Microstructure observations suggested that the peak value of dissipation factor was 0.36 at the temperature of 673K and the strain rate of 1s-1. The map exhibits flow instabilities as two domains, one is at the lower temperatures but higher strain rates, and the other is at higher temperatures and lower strains.The region at an intermediate temperature and a high strain rate is the region of the optimal mechanical working properties.


Author(s):  
Z. Abbasi ◽  
R. Ebrahimi

: The hot deformation response of a new dilute Mg alloy was investigated by means of a series of hot compression tests in the temperature and strain rate range of 375-450°C and 0.001-1 s-1 , respectively. The stress-strain behavior, microstructure evolution and processing parameters optimization were studied carefully. Micro-structural characterization studies conducted on a series of deformed samples using optical microscopy revealed that during hot deformation, the main restoration mechanism was dynamic recrystallization (DRX). In the final microstructure of the material, grain boundaries were thoroughly covered by layers of fine DRXed grains. Moreover, a strong twinning induced necklace structure was the most significant characteristic at high strain rates which was accompanied by smaller grain size in the domain material. Based on the measured stress-strain data, constitutive model was conducted on two regimes of low and high temperatures. Moreover, the processing map of the studied material was obtained and interpreted using dynamic material model (DMM). The processing map was built and divided into a feasible domain at high temperatures in the whole range of strain rates and two separated instable domains in the temperature range of 375 to 435°C at high and low strain rates of 1 and 0.001s-1 .


Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4557
Author(s):  
Mariusz Król ◽  
Przemysław Snopiński ◽  
Marek Pagáč ◽  
Jiří Hajnyš ◽  
Jana Petrů

In this work, a systematic analysis of the hot deformation mechanism and a microstructure characterization of an as-cast single α-phase Mg–4.5 Li–1.5 Al alloy modified with 0.2% TiB addition, as a grain refiner, is presented. The optimized constitutive model and hot working terms of the Mg–Li alloy were also determined. The hot compression procedure of the Mg–4.5 Li–1.5 Al + 0.2 TiB alloy was performed using a DIL 805 A/D dilatometer at deformation temperatures from 250 °C to 400 °C and with strain rates of 0.01–1 s−1. The processing map adapted from a dynamic material model (DMM) of the as-cast alloy was developed through the superposition of the established instability map and power dissipation map. By considering the processing maps and microstructure characteristics, the processing window for the Mg–Li alloy were determined to be at the deformation temperature of 590 K–670 K and with a strain rate range of 0.01–0.02 s−1.


Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 22
Author(s):  
Weiqi Kang ◽  
Yi Yang ◽  
Sheng Cao ◽  
Lei Li ◽  
Shewei Xin ◽  
...  

The hot deformation behavior of a new Al–Mn–Sc alloy was investigated by hot compression conducted at temperatures from 330 to 490 °C and strain rates from 0.01 to 10 s−1. The hot deformation behavior and microstructure of the alloy were significantly affected by the deformation temperatures and strain rates. The peak flow stress decreased with increasing deformation temperatures and decreasing strain rates. According to the hot deformation behavior, the constitutive equation was established to describe the steady flow stress, and a hot processing map at 0.4 strain was obtained based on the dynamic material model and the Prasad instability standard, which can be used to evaluate the hot workability of the alloy. The developed hot processing diagram showed that the instability was more likely to occur in the higher Zener–Hollomon parameter region, and the optimal processing range was determined as 420–475 °C and 0.01–0.022 s−1, in which a stable flow and a higher power dissipation were achieved.


2018 ◽  
Vol 913 ◽  
pp. 30-36
Author(s):  
Ran Liu ◽  
Hui Huang ◽  
Ya Liu ◽  
Li Rong

To study the hot deformation behavior of Al-Mg-Er alloy, hot compression tests were conducted on a Gleeble-1500D thermal simulator at the temperature range of 200-500°C with the strain rates from 0.001 to 10s-1. With the increase in the deformation temperature and the decrease in strain rates, the flow stress of the Al-Mg-Er alloy decreased. Processing maps were constructed to study on hot workability characteristics. The results showed that the flow stress curves exhibited the typical dynamic recrystallization characteristics and the stress decreased with the increase of deformation temperature and the decrease of strain rate. Moreover, the processing maps were established on the basis of dynamic material model and Prasad’s instability criterion.


Crystals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 125
Author(s):  
Haiping Wang ◽  
Dong Liu ◽  
Jianguo Wang ◽  
Yongzhao Shi ◽  
Yong Zheng ◽  
...  

The isothermal compression tests of the nickel-based superalloy Waspaloy were carried out under various temperatures from 1040 to 1120 °C and strain rates from 0.01 to 10 s−1 with the height reduction of 60% and the flow stress curves were obtained. The curves show that the flow stress is greatly affected by the temperature and strain rates. Regression analysis of the experimental results was carried out to learn about the deformation behavior through the Arrhenius equation and came to the conclusion that the activation energy of Waspaloy is 669.7 kJ/mol. The constitutive equation of the Waspaloy was constructed. Meanwhile, the processing maps of the Waspaloy for the power dissipation and the flow instability were constructed. The processing map of the power dissipation and the flow instability depicts that the strain plays a major role in the processing maps. The instability zone is prone to appear at higher strain rates with the increasing strains. According to the instability processing map, there are three unsafe regimes around 1040–1120 °C/1.5–10 s−1, 1040–1080 °C/0.02–0.1 s−1 and 1110–1120 °C/0.02–0.3 s−1 that should be avoided during deformation process. The power dissipation maps show that the maximum dissipation is prone to appear at low strain rates (0.01 s−1) when the strain is about 0.1~0.6 while at middle strain rates (0.1–1 s−1) when the strain is over 0.6, and when the true strain is 0.9, the optimum processing condition is around 1060–1120 °C/0.1–1 s−1. The dynamic microstructures under different temperatures and strain rates were also obtained. We concluded that lower strain rates and higher temperatures are more applicable to obtain fully-recrystallized microstructures. Based on the instability maps and the power dissipation maps and the dynamic microstructures, the optimum deformation conditions are determined to be around 1080–1100 °C/0.1–1 s−1 and 1040–1120 °C/0.01 s−1.


2010 ◽  
Vol 638-642 ◽  
pp. 3616-3621 ◽  
Author(s):  
K.P. Rao ◽  
Y.V.R.K. Prasad ◽  
Norbert Hort ◽  
Karl Ulrich Kainer

The hot working behavior of Mg-3Sn-2Ca alloy has been investigated in the temperature range 300–500 oC and strain rate range 0.0003–10 s-1, with a view to evaluate the mechanisms and optimum parameters of hot working. For this purpose, a processing map has been developed on the basis of the flow stress data obtained from compression tests. The stress-strain curves exhibited steady state behavior at strain rates lower than 0.01 s-1 and at temperatures higher than 350 oC and flow softening occurred at higher strain rates. The processing map exhibited two dynamic recrystallization domains in the temperature and strain rate ranges: (1) 300–420 oC and 0.0003–0.003 s-1, and (2) 420–500 oC and 0.003–1.0 s-1, the latter one being useful for commercial hot working. Kinetic analysis yielded apparent activation energy values of 161 and 175 kJ/mole in domains (1) and (2) respectively. These values are higher than that for self-diffusion in magnesium suggesting that the large volume fraction of intermetallic particles CaMgSn present in the matrix generates considerable back stress. The processing map reveals a wide regime of flow instability which gets reduced with increase in temperature or decrease in strain rate.


2019 ◽  
Vol 944 ◽  
pp. 887-891
Author(s):  
Long Jiang ◽  
Chun Feng ◽  
Hui Qun Liu ◽  
Le Wang ◽  
Li Hong Han ◽  
...  

A new modified low-cost titanium alloy, Ti-Al-X, was designed for petroleum drilling applications. The alloy ingots were prepared by combination of vacuum consumable electrode arc melting, forging/hot rolling, homogenization, and solid-solution/aging treatments. The hot deformation behavior of Ti-Al-X alloy was investigated by a thermal simulation machine Gleeble 1500 at temperature range of 850~1000°C with the strain rate range of 0.001 s-1~1s-1. The deformation resistance significantly decreases with the increase of deformation temperature and the strain rate. The alloy exhibits flow instability under the deformation conditions of strain rates about 0.001 s-1 and temperature above 1000°C, which should be avoided during hot working. In addition, the instability area enlarged in processing map with the increasing of true strain.


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