Effect of Hot Rolling Deformation on Superplastic Deformation Behavior of TiNP/2014Al Composite

2011 ◽  
Vol 264-265 ◽  
pp. 90-95
Author(s):  
Hui E Hu ◽  
Liang Zhen
Keyword(s):  
Strain Rate ◽  
Hot Rolling ◽  
Deformation Mechanism ◽  
Deformation Behavior ◽  
Superplastic Deformation ◽  
Grain Boundary Sliding ◽  
Composite Sheet ◽  
Boundary Sliding ◽  
Effect Of Hot Rolling ◽  
Rolling Deformation

1.5 mm, 0.7 mm and 0.3 mm thicknesses TiNP/2014Al composite sheets were obtained by hot rolling deformation carried out on as-extruded TiNP/2014Al composite rod. The effect of hot rolling deformation on high strain rate superplastic deformation behavior of the composite was researched by tensile experiment, OM, and SEM. Results show that 0.7mm thickness TiNP/2014Al composite sheet can gain the maximum elongation of 351% at 818 K and 3.3×10-1 s-1, and the m value is 0.43. The optimum strain rate increases with decreasing thickness of the TiNP/2014Al composite sheets. Flow stress and work hardening ability show contrary change tendency to optimum strain rate. The 0.7 mm thickness TiNP/2014Al composite sheet has medium flow resistance stress and shows excellent stability of plastic flow. Fracture surfaces show that the main superplastic deformation mechanism of the TiNP/2014Al composite includes in grain boundary sliding. Subgrain boundary sliding maybe another superplastic deformation mechanism.

A Model for the Effects of Strain Rate and Temperature on the Deformation Behavior of Ultrafine-Grained Metals

2011 ◽  
Vol 291-294 ◽  
pp. 1173-1177
Author(s):  
Zi Ling Xie ◽  
Lin Zhu Sun ◽  
Fang Yang
Keyword(s):  
Grain Boundary ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Boundary Diffusion ◽  
Rate Sensitivity ◽  
Grain Boundary Sliding ◽  
Dislocation Slip ◽  
Deformation Response ◽  
Ultrafine Grained ◽  
Boundary Sliding

A theoretical model is developed to account for the effects of strain rate and temperature on the deformation behavior of ultrafine-grained fcc Cu. Three mechanisms, including dislocation slip, grain boundary diffusion, and grain boundary sliding are considered to contribute to the deformation response simultaneously. Numerical simulations show that the strain rate sensitivity increases with decreasing grain size and strain rate, and that the flow stress and tensile ductility increase with either increasing strain rate or decreasing deformation temperature.

STUDY ON HIGH STRAIN RATE COMPRESSION SUPERPLASTICITY OF AS-EXTRUDED AZ31 MAGNESIUM ALLOY

2013 ◽  
Vol 27 (19) ◽  
pp. 1341022 ◽  
Author(s):  
FEI LIN ◽  
JIE LI ◽  
HONGWEI ZHAO ◽  
LULU SUN ◽  
ZHITONG CHEN ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
High Strain Rate ◽  
Strain Rate ◽  
Superplastic Deformation ◽  
High Strain ◽  
Orthogonal Experiment ◽  
True Strain ◽  
Grain Boundary Sliding ◽  
Az31 Magnesium Alloy ◽  
Boundary Sliding

The grain size of as-extruded AZ31 magnesium alloy was refined by isothermal annealing pretreatment through orthogonal experiment. By using the Gleeble-3800 thermal simulator, the compression superplasticity of as-extruded AZ31 magnesium alloy was studied. The high strain rate superplastic compression was realized. The process parameters of the superplastic compression were established and the mechanism of the superplastic deformation was analyzed. The effects of deformation temperature and strain rate on the superplastic flow were investigated. The results indicated that at 250°C–300°C and strain rate at 1×10-2 s -1, the true strain values were all more than 2.03. As the temperature was 300°C and the strain rate was 1×10-2 s -1–1×10 s -1, the true strain values were all more than 2.18. The results showed that the as-extruded AZ31 magnesium alloy being refined presented good compression superplasticity. The main mechanism for the superplastic compressive deformation of the as-extruded AZ31 magnesium alloy was grain-boundary sliding, meanwhile, dynamic recrystallization also played a harmonious role during the superplastic deformation.

Superplastic Deformation Behavior in Dual-Phase Mg-Ca Alloy

2016 ◽  
Vol 838-839 ◽  
pp. 256-260
Author(s):  
Takahiko Yano ◽  
Naoko Ikeo ◽  
Hiroyuki Watanabe ◽  
Toshiji Mukai
Keyword(s):  
Activation Energy ◽  
Grain Boundary ◽  
Deformation Behavior ◽  
Superplastic Deformation ◽  
Boundary Diffusion ◽  
Rate Sensitivity ◽  
Grain Boundary Sliding ◽  
Dual Phase ◽  
Elongation To Failure ◽  
Boundary Sliding

Superplastic deformation behavior was investigated for a dual-phase Mg-Ca alloy. The elongation-to-failure reached more than 120% with the strain rate sensitivity, m, over 0.4. The activation energy required for the deformation was estimated to be 98 kJ/mol which is close to the activation energy for grain boundary diffusion in magnesium. Therefore, the superplastic deformation mechanism was suggested to be the grain boundary sliding rate, which is controlled by boundary diffusion.

scholarly journals Superplastic Deformation and Dynamic Recrystallization of a Novel Disc Superalloy GH4151

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3667 ◽  
Author(s):  
Shaomin Lv ◽  
Chonglin Jia ◽  
Xinbo He ◽  
Zhipeng Wan ◽  
Xinxu Li ◽  
...  
Keyword(s):  
Activation Energy ◽  
Grain Boundary ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Superplastic Deformation ◽  
Optical Microscope ◽  
Grain Boundary Sliding ◽  
Experimental Conditions ◽  
Average Activation Energy ◽  
Boundary Sliding

The superplastic deformation of a hot-extruded GH4151 billet was investigated by means of tensile tests with the strain rates of 10−4 s−1, 5 × 10−4 s−1 and 10−3 s−1 and at temperatures at 1060 °C, 1080 °C and 1100 °C. The superplastic deformation of the GH4151 alloy was reported here for the first time. The results reveal that the uniform fine-grained GH4151 alloy exhibited an excellent superplasticity and high strain rate sensitivity (exceeded 0.5) under all experimental conditions. It was found that the increase of strain rate resulted in an increased average activation energy for superplastic deformation. A maximum elongation of 760.4% was determined at a temperature of 1080 °C and strain rate of 10−3 s−1. The average activation energy under different conditions suggested that the superplastic deformation with 1 × 10−4 s−1 in this experiment is mainly deemed as the grain boundary sliding controlled by grain boundary diffusion. However, with a higher stain rate of 5 × 10−4 s−1 and 1 × 10−3 s−1, the superplastic deformation is considered to be grain boundary sliding controlled by lattice diffusion. Based on the systematically microstructural examination using optical microscope (OM), SEM, electron backscatter diffraction (EBSD) and TEM techniques, the failure and dynamic recrystallization (DRX) nucleation mechanisms were proposed. The dominant nucleation mechanism of dynamic recrystallization (DRX) is the bulging of original grain boundaries, which is the typical feature of discontinuous dynamic recrystallization (DDRX), and continuous dynamic recrystallization (CDRX) is merely an assistant mechanism of DRX. The main contributions of DRX on superplasticity elongation were derived from its grain refinement process.

Superplastic Deformation Mechanisms in a Fine-Grained, Yttria-stabilized Tetragonal Zirconia Polycrystal (Y-TZP)

1990 ◽  
Vol 196 ◽  
Author(s):  
T. G. Nieh ◽  
J. Wadsworth
Keyword(s):  
Grain Boundary ◽  
Strain Rate ◽  
Grain Growth ◽  
Strain Rate Sensitivity ◽  
Superplastic Deformation ◽  
Rate Sensitivity ◽  
Grain Boundary Sliding ◽  
Boundary Triple ◽  
Sliding Mechanism ◽  
Boundary Sliding

ABSTRACTConcurrent grain growth, and in particular, dynamic grain growth, was observed to take place during superplastic deformation of Y-TZP. As a result of this concurrent grain growth, the measured strain rate sensitivity was found to be lower than that measured under constantstructure conditions. In the present paper, data obtained from the superplastic deformation of YTZP under constant-structure conditions are presented. It is demonstrated that the strain rate sensitivity values are generally higher than 0.5, when measured from the grain size-compensated data; this result suggests a grain boundary sliding mechanism. Microstructures from samples prior to and after superplastic deformation reveal grains which are essentially equiaxed; this observation is also consistent with a grain boundary sliding mechanism. Both high-resolution images of grain boundary triple points using transmission electron microscopy, and fracture surface studies using Auger electron spectroscopy and X-ray photoelectron spectroscopy indicate that there is no evidence for the presence of glassy phases at grain boundaries in Y-TZP.

A Study on Superplastic Behavior and Microstructural Evolution of an Isothermally Forged TiAl Based Alloy

2007 ◽  
Vol 551-552 ◽  
pp. 463-466
Author(s):  
Hua Ding ◽  
D. Song ◽  
Z.Q. Pan ◽  
C.P. Zhang ◽  
J.Z. Cui
Keyword(s):  
Strain Rate ◽  
Superplastic Deformation ◽  
Boundary Migration ◽  
Rate Sensitivity ◽  
Grain Boundary Sliding ◽  
Sensitivity Index ◽  
Superplastic Behavior ◽  
Strain Rate Sensitivity Index ◽  
Boundary Sliding ◽  
Equiaxed Grains

Superplastic behavior and microstructure evolution of an isothermally forged Ti-47Al-1Cr-1V-1.5Mo-1.5Nb alloy were investigated. The results showed that the strain rate sensitivity index, m, increased with strain during the superplastic deformation, and it kept as a constant when the strain reached a certain value. The maximum value of m was 0.53 at 900°C and strain rate of 5x10-4 s-1. During the superplastic deformation, the as received material with lamellae and subgrains were refined due to dynamic recrystallization, and small and equiaxed grains with high angle boundaries were formed, creating a better condition for superplastic deformation. Grain boundary sliding and boundary migration were the main superplastic deformation mechanisms and slip and twining were also very important during the superplastic deformation of the alloy.

Research of Superplasticity Deformation Behavior about Coarse-Grain Ti-22Al-25Nb Alloy

2013 ◽  
Vol 818 ◽  
pp. 9-13 ◽  
Author(s):  
Yu Zhi Li ◽  
Ze Kun Yao ◽  
Wei Zhou ◽  
Chun Qin ◽  
Hong Zhen Guo ◽  
...  
Keyword(s):  
Tensile Test ◽  
Strain Rate ◽  
Deformation Mechanism ◽  
Deformation Behavior ◽  
Superplastic Deformation ◽  
Coarse Grain ◽  
Semisolid Slurry ◽  
Volume Percent ◽  
Two Phases ◽  
O Phase

This study investigates the superplastic deformation mechanism of coarse-grain materials .Superplasticity deformation behavior of Ti-22Al-25Nb alloy with 200~410μm coarse grain has been investigated through tensile test at 940~990°C and 3.3× (10-2~10-4) s-1 strain rate. Results prove coarse-grain Ti-22Al-25Nb alloy primary depends on slipping of crystal planes between two phases to achieve superplasticity. Transformation from lath O phase to ring equiaxed O phase occurs as temperature rises and its volume percent falls, but percentage of recrystallized B2 phase increases. Dislocation can move round ring equiaxed O phase. Good plasticity can be preserved because O phase can flow as solid particle in semisolid slurry in B2 grain.

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