The Research on Superplasticity of Two New Ti Alloys

2007 ◽  
Vol 551-552 ◽  
pp. 405-410
Author(s):  
Yong Qing Zhao ◽  
Heng Lei Qu ◽  
L.Y. Zeng
Keyword(s):  
Strain Rate ◽  
Tensile Deformation ◽  
Structural Evolution ◽  
High Strength ◽  
Grain Boundary Sliding ◽  
Dislocation Creep ◽  
Ti Alloy ◽  
Maximum Elongation ◽  
Tensile Deformation Behavior ◽  
Boundary Sliding

The superplastic tensile deformation behavior and structural evolution of two kinds of α+β titanium alloys were investigated in this paper, one is a new high strength high toughness Ti alloy with damage tolerance called TC21, and the other is a new superplastic Ti alloy so called Ti-SP2500. The results indicated that TC21 alloy has good superplasticity at the temperature from 720 to 960 and with the strain rate of 5.510-5s-1∼1.110-2s-1. On the optimal superplastic condition, the maximum elongation is over 1300%. During the superplastic tensile deformation, the dynamic recrystallization occurs in deformation zone of the specimens and the superplasticity is improved. Ti-SP2500 alloy has good superplasticity at the temperature from 720°C to 800°C and with the strain rate of 6.67 10-4s-1∼1.1110-2s-1. The maximum elongation for Ti-SP2500 alloy will exceed 2200% at 780°C with the strain rate of 5.5610-3s-1. Its superplastic deformation mechanism is controlled by grain boundary sliding, and the grain deformation and dislocation creep has the coordinating action.

Tensile Properties and Microstructure of ZK60 Magnesium Alloys at High Temperature

2011 ◽  
Vol 117-119 ◽  
pp. 1113-1116
Author(s):  
Wen Jie Cheng ◽  
Fu Xiao Chen
Keyword(s):  
Magnesium Alloy ◽  
Strain Rate ◽  
Flow Behavior ◽  
Rate Sensitivity ◽  
Grain Boundary Sliding ◽  
Maximum Elongation ◽  
Superplastic Behavior ◽  
Boundary Sliding ◽  
Zk60 Magnesium Alloy ◽  
Main Deformation

Using tensile test of ZK60 magnesium alloy, the superplastic flow behavior was studied. The deformation temperature was set as 280°C, 310°C,340°C, 370°C and 400°C while strain rate was 1×10-1s-1, 1×10-2s-1, 1×10-3s-1 and 1×10-4s-1. The results showed that the perfect superplastic behavior was presented at 370°C and =1×10-4s-1 and the maximum elongation could be 133.7%. The biggest factor of strain rate sensitivity was 0.62. The microstructure of the fracture was analyzed used SEM and the results showed that the main deformation mechanism of ZK60 magnesium alloy was grain boundary sliding.

The effect of strain rates on tensile deformation of ultrafine-grained copper

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744014
Author(s):  
M. Li ◽  
Q. W. Jiang
Keyword(s):  
Strain Rate ◽  
Deformation Behavior ◽  
Room Temperature ◽  
Tensile Deformation ◽  
Strain Rates ◽  
Roll Bonding ◽  
Fracture Elongation ◽  
Tensile Deformation Behavior ◽  
Ultrafine Grained ◽  
Flow Stress Level

Tensile deformation behavior of ultrafine-grained (UFG) copper processed by accumulative roll-bonding (ARB) was studied under different strain rates at room temperature. It was found that the UFG copper under the strain rate of 10[Formula: see text] s[Formula: see text] led to a higher strength (higher flow stress level), flow stability (higher stress hardening rate) and fracture elongation. In the fracture surface of the sample appeared a large number of cleavage steps under the strain rate of 10[Formula: see text] s[Formula: see text], indicating a typical brittle fracture mode. When the strain rate is 10[Formula: see text] or 10[Formula: see text] s[Formula: see text], a great amount of dimples with few cleavage steps were observed, showing a transition from brittle to plastic deformation with increasing strain rate.

scholarly journals Additive Manufacturing Enabled by Electrospinning for Tougher Bio-Inspired Materials

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Komal Agarwal ◽  
Yinning Zhou ◽  
Hashina Parveen Anwar Ali ◽  
Ihor Radchenko ◽  
Avinash Baji ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Surface Treatment ◽  
Tensile Deformation ◽  
High Strength ◽  
High Impact ◽  
Synthetic Analogue ◽  
Amino Groups ◽  
High Impact Energy ◽  
Tensile Deformation Behavior ◽  
Complex Architecture

Nature has taught us fascinating strategies to design materials such that they exhibit superior and novel properties. Shells of mantis club have protein fibres arranged in a 3D helicoidal architecture that give them remarkable strength and toughness, enabling them to absorb high-impact energy. This complex architecture is now possible to replicate with the recent advances in additive manufacturing. In this paper, we used melt electrospinning to fabricate 3D polycaprolactone (PCL) fibrous design to mimic the natural helicoidal structures found in the shells of the mantis shrimp’s dactyl club. To improve the tensile deformation behavior of the structures, the surface of each layer of the samples were treated with carboxyl and amino groups. The toughness of the surface-treated helicoidal sample was found to be two times higher than the surface-treated unidirectional sample and five times higher than the helicoidal sample without surface treatment. Free amino groups (NH2) were introduced on the surface of the fibres and membrane via surface treatment to increase the interaction and adhesion among the different layers of membranes. We believe that this represents a preliminary feasibility in our attempt to mimic the 3D helicoidal architectures at small scales, and we still have room to improve further using even smaller fibre sizes of the modeled architectures. These lightweight synthetic analogue materials enabled by electrospinning as an additive manufacturing methodology would potentially display superior structural properties and functionalities such as high strength and extreme toughness.

scholarly journals The role of grain size evolution in the rheology of ice: implications for reconciling laboratory creep data and the Glen flow law

2021 ◽  
Vol 15 (9) ◽  
pp. 4589-4605
Author(s):  
Mark D. Behn ◽  
David L. Goldsby ◽  
Greg Hirth
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Stress Exponent ◽  
Ice Sheets ◽  
Grain Boundary Sliding ◽  
Dislocation Creep ◽  
Ice Flow ◽  
Size Evolution ◽  
Boundary Sliding ◽  
Flow Law

Abstract. Viscous flow in ice is often described by the Glen flow law – a non-Newtonian, power-law relationship between stress and strain rate with a stress exponent n ∼ 3. The Glen law is attributed to grain-size-insensitive dislocation creep; however, laboratory and field studies demonstrate that deformation in ice can be strongly dependent on grain size. This has led to the hypothesis that at sufficiently low stresses, ice flow is controlled by grain boundary sliding, which explicitly incorporates the grain size dependence of ice rheology. Experimental studies find that neither dislocation creep (n ∼ 4) nor grain boundary sliding (n ∼ 1.8) have stress exponents that match the value of n ∼ 3 in the Glen law. Thus, although the Glen law provides an approximate description of ice flow in glaciers and ice sheets, its functional form is not explained by a single deformation mechanism. Here we seek to understand the origin of the n ∼ 3 dependence of the Glen law by using the “wattmeter” to model grain size evolution in ice. The wattmeter posits that grain size is controlled by a balance between the mechanical work required for grain growth and dynamic grain size reduction. Using the wattmeter, we calculate grain size evolution in two end-member cases: (1) a 1-D shear zone and (2) as a function of depth within an ice sheet. Calculated grain sizes match both laboratory data and ice core observations for the interior of ice sheets. Finally, we show that variations in grain size with deformation conditions result in an effective stress exponent intermediate between grain boundary sliding and dislocation creep, which is consistent with a value of n = 3 ± 0.5 over the range of strain rates found in most natural systems.

scholarly journals Dynamic recrystallization behavior of the Ta-containing TiAl alloy in isothermal deformation

2020 ◽  
Vol 321 ◽  
pp. 12008
Author(s):  
Y.Y. Luo ◽  
X.N. Mao ◽  
H.Y. Yang ◽  
Y.F. Yin ◽  
Z.Z. Zhao ◽  
...  
Keyword(s):  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Tial Alloy ◽  
Grain Boundary Sliding ◽  
Strain Rates ◽  
Recrystallization Behavior ◽  
Compression Process ◽  
Dynamic Recrystallization Behavior ◽  
Boundary Sliding ◽  
Mechanical Twins

The dynamic recrystallization behavior of as-cast Ti-46.5Al-3Ta-2Cr-0.2W alloy during isothermal compression process with nominal deformation of 50% and strain rates from 0.01s to 1s was investigated by electron microscopy. The results showed that the deformation mechanism of this alloy can be concluded as grain boundary sliding and mechanical twins, which induce the final dynamic recrystallization. The phase boundary bulging was found to be the major nucleation mechanism responsible for the lamellar globularization and the formation of recrystallized γ grains inside the lamellar colony under the high strain rate. The recrystallized γ grains induced by the twinning is the main mechanism for refining α2 lamellar microstructures under low strain rate.

Effects of temperature and strain rate on tensile deformation behavior of superalloy UNS N10276

2017 ◽  
Vol 699 ◽  
pp. 88-98 ◽  
Author(s):  
Enxiang Pu ◽  
Wenjie Zheng ◽  
Zhigang Song ◽  
Han Feng ◽  
Feng Yang ◽  
...  
Keyword(s):  
Strain Rate ◽  
Deformation Behavior ◽  
Tensile Deformation ◽  
Tensile Deformation Behavior ◽  
Effects Of Temperature
Sign in / Sign up

Export Citation Format

Share Document