scholarly journals Vacuum superplastic deformation behavior of a near-alpha titanium alloy TA32

2020 ◽  
Vol 321 ◽  
pp. 11018
Author(s):  
Chao Cheng ◽  
Weitang Zhang ◽  
Zhiyong Chen ◽  
Liang Jin ◽  
Qingjiang Wang
Keyword(s):  
Titanium Alloy ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Superplastic Deformation ◽  
Surface Oxidation ◽  
Superplastic Forming ◽  
Grain Boundary Sliding ◽  
Texture Intensity ◽  
Near Space ◽  
Alpha Titanium

TA32 is a heat-resistant titanium alloy developed for superplastic forming in fabrication of near-space supersonic aerocraft. Clarification of superplastic deformation behavior is important to the optimization of forming parameters. Superplastic tensile test was conducted in vacuum to eliminate the effect of surface oxidation on experimental data, the test temperature and strain rate varied from 900oC to 960oC and 5.32×10-4 to 2.08×10-2s-1, respectively. It was observed that the size of equiaxed α grains exhibited a trend of coarsening with the increase of temperature and decrease of strain rate. Textures of deformed specimens exhibited random distribution with a decreased texture intensity compared with the as-received materials. The superplastic deformation mechanism of TA32 alloy was dominated by grain boundary sliding, which is accommodated by grain rotation and dynamic recrystallization.

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.

High Strain Rate Superplastic Deformation Behavior of TiNP/2014Al Composite

2010 ◽  
Vol 97-101 ◽  
pp. 1633-1636
Author(s):  
Hui E Hu ◽  
Liang Zhen
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Superplastic Deformation ◽  
High Strain ◽  
Volume Fraction ◽  
Tensile Tests ◽  
Grain Boundary Sliding ◽  
Powder Metallurgy Method ◽  
Accommodation Mechanism

TiNP/2014Al composite was prepared by powder metallurgy method with a reinforcement volume fraction of 15%. High strain rate superplastic deformation behavior of the TiNP/2014Al composite was investigated by tensile tests conducted at 818 K with different strain rates range from 1.7×100 to 1.7×10-3 s-1, DSC, OM, TEM and SEM. It is shown that a maximum elongation of 351% is achieved at 818 K and 3.3×10-1 s-1. The curve of value can be divided into two stages with the variation of strain rate and the critical strain rate is 10-1 s-1. Plastic deformation of the TiNP/2014Al composite at 818 K and 3.3×10-1 s-1 is conducted at an almost constant maximum value of flow stress. High strain rate superplastic deformation mechanism of the TiNP/2014Al composite deformed at 818 K with the strain rate of 3.3×10-1 s-1 is grain boundary sliding accommodation mechanism plus liquid phase helper accommodation mechanism.

scholarly journals Superplastic Deformation Behavior of Rolled Mg-8Al-2Sn and Mg-8Al-1Sn-1Zn Alloys at High Temperatures

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1074 ◽  
Author(s):  
Shao-You Zhang ◽  
Cheng Wang ◽  
Long-Qing Zhao ◽  
Pin-Kui Ma ◽  
Jia-Wang Song ◽  
...  
Keyword(s):  
High Temperature ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Superplastic Deformation ◽  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Tensile Deformation ◽  
Tensile Elongation ◽  
Grain Boundary Sliding

The high-temperature superplastic deformation behavior of rolled Mg-8Al-2Sn (AT82) and Mg-8Al-1Sn-1Zn (ATZ811) alloys were investigated in this study. During tensile deformation at 573 K, no obvious grain growth occurred in both alloys, because of the high-volume fraction of second phases located at grain boundaries. Meanwhile, texture weakening was observed, suggesting that grain boundary sliding (GBS) is the dominant superplastic deformation mechanism, which agreed well with the strain rate sensitivity (m) and the activation energy (Q) calculations. The microstructural evolution during tensile deformation manifested that there were more and larger cavities in AT82 than ATZ811 during high-temperature tensile deformation. Therefore, superior superplasticity was found in the ATZ811 alloy that presented a tensile elongation of ~510% under a strain rate of 10−3 s−1 at 573 K, in contrast to the relatively inferior elongation of ~380% for the AT82 alloy. Meanwhile, good tensile properties at ambient temperature were also obtained in ATZ811 alloy, showing the ultimate tensile strength (UTS) of ~355 MPa, yield strength (YS) of ~250 MPa and elongation of ~18%. Excellent mechanical performance at both ambient and elevated temperatures can be realized by using economical elements and conventional rolling process, which is desirable for the industrial application of Mg alloy sheets.

scholarly journals High-Temperature Deformation Behavior and Microstructural Characterization of Ti-35421 Titanium Alloy

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3623 ◽  
Author(s):  
Danying Zhou ◽  
Hua Gao ◽  
Yanhua Guo ◽  
Ying Wang ◽  
Yuecheng Dong ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Deformation Temperature ◽  
Phase Region ◽  
Temperature Deformation ◽  
Β Phase ◽  
Α Phase

A self-designed Ti-35421 (Ti-3Al-5Mo-4Cr-2Zr-1Fe wt%) titanium alloy is a new type of low-cost high strength titanium alloy. In order to understand the hot deformation behavior of Ti-35421 alloy, isothermal compression tests were carried out under a deformation temperature range of 750–930 °C with a strain rate range of 0.01–10 s−1 in this study. Electron backscatter diffraction (EBSD) was used to characterize the microstructure prior to and post hot deformation. The results show that the stress–strain curves have obvious yielding behavior at a high strain rate (>0.1 s−1). As the deformation temperature increases and the strain rate decreases, the α phase content gradually decreases in the α + β phase region. Meanwhile, spheroidization and precipitation of α phase are prone to occur in the α + β phase region. From the EBSD analysis, the volume fraction of recrystallized grains was very low, so dynamic recovery (DRV) is the dominant deformation mechanism of Ti-35421 alloy. In addition to DRV, Ti-35421 alloy is more likely to occur in continuous dynamic recrystallization (CDRX) than discontinuous dynamic recrystallization (DDRX).

High-Temperature Deformation of Magnesium ElektronTM 43

2012 ◽  
Vol 735 ◽  
pp. 93-100
Author(s):  
Alexander J. Carpenter ◽  
Anthony J. Barnes ◽  
Eric M. Taleff
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Superplastic Forming ◽  
Solute Drag ◽  
Grain Boundary Sliding ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Fine Grained ◽  
Boundary Sliding

Complex sheet metal components can be formed from lightweight aluminum and magnesium sheet alloys using superplastic forming technologies. Superplastic forming typically takes advantage of the high strain-rate sensitivity characteristic of grain-boundary-sliding (GBS) creep to obtain significant ductility at high temperatures. However, GBS creep requires fine-grained materials, which can be expensive and difficult to manufacture. An alternative is provided by materials that exhibit solute-drag (SD) creep, a mechanism that also produces elevated values of strain-rate sensitivity. SD creep typically operates at lower temperatures and faster strain rates than does GBS creep. Unlike GBS creep, solute-drag creep does not require a fine, stable grain size. Previous work by Boissière et al. suggested that the Mg-Y-Nd alloy, essentially WE43, deforms by SD creep at temperatures near 400°C. The present investigation examines both tensile and biaxial deformation behavior of ElektronTM 43 sheet, which has a composition similar to WE43, at temperatures ranging from 400 to 500°C. Data are presented that provide additional evidence for SD creep in Elektron 43 and demonstrate the remarkable degree of biaxial strain possible under this regime (>1000%). These results indicate an excellent potential for producing complex 3-D parts, via superplastic forming, using this particular heat-treatable Mg alloy.

scholarly journals High Strain Rate Superplasticity in Al-Zn-Mg-Based Alloy: Microstructural Design, Deformation Behavior, and Modeling

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2098 ◽  
Author(s):  
Olga Yakovtseva ◽  
Maria Sitkina ◽  
Ahmed O. Mosleh ◽  
Anastasia Mikhaylovskaya
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Superplastic Deformation ◽  
High Strain ◽  
Flow Behavior ◽  
Constant Strain Rate ◽  
Superplastic Forming ◽  
High Strength ◽  
Strain Rate Range ◽  
Strain Rates

Increasing the strain rate at superplastic forming is a challenging technical and economic task of aluminum forming manufacturing. New aluminum sheets exhibiting high strain rate superplasticity at strain rates above 0.01 s−1 are required. This study describes the microstructure and the superplasticity properties of a new high-strength Al-Zn-Mg-based alloy processed by a simple thermomechanical treatment including hot and cold rolling. The new alloy contains Ni to form Al3Ni coarse particles and minor additions of Zr (0.19 wt.%) and Sc (0.06 wt.%) to form nanoprecipitates of the L12-Al3 (Sc,Zr) phase. The design of chemical and phase compositions of the alloy provides superplasticity with an elongation of 600–800% in a strain rate range of 0.01 to 0.6/s and residual cavitation less than 2%. A mean elongation-to-failure of 400% is observed at an extremely high constant strain rate of 1 s−1. The strain-induced evolution of the grain and dislocation structures as well as the L12 precipitates at superplastic deformation is studied. The dynamic recrystallization at superplastic deformation is confirmed. The superplastic flow behavior of the proposed alloy is modeled via a mathematical Arrhenius-type constitutive model and an artificial neural network model. Both models exhibit good predictability at low and high strain rates of superplastic deformation.

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