An Experimental Study of Interfacial Friction-Hot Ring Compression

1992 ◽  
Vol 114 (1) ◽  
pp. 13-18 ◽  
Author(s):  
F. Wang ◽  
J. G. Lenard
Keyword(s):  
Experimental Study ◽  
True Strain ◽  
Interfacial Friction ◽  
Strain Rates ◽  
Compression Tests ◽  
Temperature Range ◽  
Ring Compression ◽  
Constant Friction

Ring compression tests were conducted at constant true strain rates in the temperature range of 900–975°C. The constant friction shear factor, m, was determined using a calibration chart. Scaling was permitted during the experiments in which a glass based lubricant was also used. Frictional conditions were affected most by the rate of strain; increasing it led to lower values of m.

Hot working of SP-700 titanium alloy with lamellar α + β starting structure using a processing map

2020 ◽  
Vol 111 (4) ◽  
pp. 297-306
Author(s):  
Amir Hosein Sheikhali ◽  
Maryam Morakkabati
Keyword(s):  
Titanium Alloy ◽  
Strain Rate ◽  
Hot Deformation ◽  
Processing Map ◽  
Microstructural Analysis ◽  
Shear Bands ◽  
Alpha Phase ◽  
Strain Rates ◽  
Compression Tests ◽  
Temperature Range

Abstract In this study, hot deformation behavior of SP-700 titanium alloy was investigated by hot compression tests in the temperature range of 700-9508C and at strain rates of 0.001, 0.1, and 1 s-1. Final mechanical properties of the alloy (hot compressed at different strain rates and temperatures) were investigated using a shear punch testing method at room temperature. The flow curves of the alloy indicated that the yield point phenomenon occurs in the temperature range of 800- 9508C and strain rates of 0.1 and 1 s-1. The microstructural analysis showed that dynamic globularization of the lamellar α phase starts at 7008C and completes at 8008C. The alpha phase was completely eliminated from b matrix due to deformation- induced transformation at 8508C. The microstructure of specimens compressed at 8508C and strain rates of 0.001 and 0.1 s-1showed the serration of beta grain boundaries, whereas partial dynamic recrystallization caused a necklace structure by increasing strain rate up to 1 s-1. The specimen deformed at 7008C and strain rate of 1 s-1was located in the instability region and localized shear bands formed due to the low thermal conductivity of the alloy. The processing map of the alloy exhibited a peak efficiency domain of 54% in the temperature range of 780-8108C and strain rates of 0.001- 0.008 s-1. The hot deformation activation energy of the alloy in the α/β region (305.5 kJ mol-1) was higher than that in the single-phase β region (165.2 kJ mol-1) due to the dynamic globularization of the lamellar a phase.

Hot Deformation Behavior of Q235 Steel during Isothermal Compression at Elevated Temperature

2015 ◽  
Vol 1088 ◽  
pp. 186-190 ◽  
Author(s):  
Ben Yang ◽  
Zhou Zheng ◽  
Li Xin Wang ◽  
Yong Gang Wu
Keyword(s):  
Constitutive Relation ◽  
True Strain ◽  
Strain Curve ◽  
Strain Rates ◽  
Compression Tests ◽  
Q235 Steel ◽  
Wide Range ◽  
Allowable Range ◽  
Experimental Values ◽  
Jc Model

The isothermal hot compression tests of Q235 steel over a wide range of temperatures (1023-1123 K), strain (0.7) and strain rates (1、5、10 s−1) were performed on Gleeble-1500 system. The results show that when the deformation temperature is constant, as the strain rate increases, the flow stress also increases; Use the JC model to establish constitutive relation equation with true stress-true strain curve. And compare the prediction value of the constitutive relation equation with the experimental values, the relative error between the two is within the allowable range, indicating that the JC model constitutive relation equation applicable for the thermal deformation of Q235 steel.

scholarly journals Hot Deformation Behavior and Processing Maps of Fe-30Mn-0.11C Steel

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1940 ◽  
Author(s):  
Jianmei Kang ◽  
Yuhui Wang ◽  
Zhimeng Wang ◽  
Yiming Zhao ◽  
Yan Peng ◽  
...  
Keyword(s):  
Dynamic Recrystallization ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
True Strain ◽  
Peak Stress ◽  
Strain Rates ◽  
Processing Maps ◽  
Compression Tests ◽  
Hot Deformation Behavior ◽  
High Deformation

Hot deformation behavior of Fe-30Mn-0.11C steel was investigated. Hot compression tests were carried out at various temperatures ranging from 800 °C to 1200 °C and at different strain rates of 0.01 s−1 to 10 s−1. The constitutive equation based on peak stress was established. Hot processing maps at different strains and recrystallization diagrams were also established and analyzed. The results show that dynamic recrystallization easily occur at high deformation temperatures and low strain rates. Safe and unstable zones are determined at the true strain of 0.6 and 0.7, and the hot deformation process parameters of partial dynamic recrystallization of the tested steel are also obtained.

Impact/Indentation Strength of Iceberg and Artificial Snow Ice

1988 ◽  
Vol 110 (1) ◽  
pp. 87-93 ◽  
Author(s):  
H. El-Tahan ◽  
A. S. J. Swamidas ◽  
M. Arockiasamy
Keyword(s):  
Experimental Study ◽  
Impact Strength ◽  
Uniaxial Compression ◽  
Level Surface ◽  
Strain Rates ◽  
Compression Tests ◽  
Indentation Tests ◽  
The Impact ◽  
Uniaxial Strength

The paper presents an experimental study on the indentation and the impact strengths of iceberg and artificial snow ice. Indentation and uniaxial tests were carried out under various strain rates and confining conditions. Uniaxial compression tests were carried out on cylindrical specimens. Indentation tests were carried out on confined/unconfined rectangular ice blocks through cylindrical/flat-circular indenters. For iceberg ice, the average uniaxial strength varied between 6.6 to 7.5 MPa and the indentation strength between 17.0 to 34.0 MPa, under various strain rates. Impact was achieved by dropping a steel cylindrical indenter, weighing 60.0 kg, onto the level surface of confined/unconfined ice blocks; the velocity of impact was 2.0 m/s. The maximum (average of seven values) impact strength of iceberg ice obtained was 17.35 MPa, while that of artificial snow ice was 20.54 MPa.

High-Temperature Deformation Behavior of the γ Alloy Ti-48Ai-2Cr-2Nb

1990 ◽  
Vol 213 ◽  
Author(s):  
Donald S. Shih ◽  
Gary K. Scarr
Keyword(s):  
High Temperature ◽  
Strain Rate ◽  
True Strain ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Strain Rates ◽  
Compression Tests ◽  
Uniform Deformation ◽  
Good Workability ◽  
Low Strain Rate

ABSTRACTThe hot-workability of a two-phase (γ+α2) alloy, Ti-48A1-2Cr-2Nb, has been studied by conducting isothermal compression tests to 0.8 true strain over the temperature range of 975–1200°C at strain rates between 1×l0−1 and 3×10−3s−1. A deformation map showing temperature, strain rate, soundness of deformation, and isostress contours was constructed. Good workability is found from the low temperature/low strain rate regime to combinations of high temperature and either high or low strain rate. The upper-limit flow stress for good workability is between 450 and 500 MPa. Deformation induced softening occurs at all conditions. SEM and TEM examinations of the deformed specimens reveal that non-uniform deformation takes place at all strain rates, but cracking occurs mostly at high strain rates (e.g. 1×10−1s−1), especially combined with low temperatures. The cracking appears to progress primarily along γ/α2interfaces. It is thought that non-uniform deformation develops channels of shear bands, which in turn promote localized recrystallization, thus accommodating higher strains.

Mechanical properties and dislocation dynamics of GaP

1989 ◽  
Vol 4 (2) ◽  
pp. 355-360 ◽  
Author(s):  
Ichiro Yonenaga ◽  
Koji Sumino
Keyword(s):  
Mechanical Properties ◽  
Dislocation Dynamics ◽  
Dynamic State ◽  
Strain Rates ◽  
Compression Tests ◽  
Stress Strain ◽  
Temperature Range ◽  
Strain Behavior ◽  
Defect Complexes ◽  
Impurity Defect

Mechanical properties of GaP crystals are investigated in the temperature range 600–900 °C by means of compression tests. Stress-strain characteristics of a GaP crystal in the temperature range 600–800 °C are very similar to those of a GaAs crystal in the temperature range 450–600 °C. The dynamic state of dislocations during deformation is determined by means of the strain-rate cycling technique. The deformation of GaP is found to be controlled by the dislocation processes the same as those in other kinds of semiconductors such as Si, Ge, and GaAs. The velocity v of dislocations that control deformation is deduced to be v = v0 τ exp(–2.2 eV/kT) as a function of the stress τ and the temperature T, where v0 is a constant and k the Boltzmann constant. The Portevin-LeChatelier effect is observed in the stress-strain behavior in the deformation at high temperatures and under low strain rates, which may be attributed to the locking of dislocations by impurities or impurity-defect complexes.

Flow Stress Behavior and Deformation Characteristics of Ti-22Al-25Nb Alloys at Elevated Temperature

2005 ◽  
Vol 475-479 ◽  
pp. 825-828
Author(s):  
Xiao Bo Liang ◽  
Shi Qiong Li ◽  
Yun Jun Cheng ◽  
Jian Wei Zhang
Keyword(s):  
Strain Rate ◽  
Dynamic Recovery ◽  
Orthorhombic Phase ◽  
Strain Rates ◽  
Beta Transus ◽  
Compression Tests ◽  
Flow Curves ◽  
Temperature Range ◽  
Softening Mechanism ◽  
Yield Phenomena

The characteristics of deformation of an orthorhombic phase based alloy, Ti-22Al-25Nb (at%), have been studied by hot compression tests in the temperature range of 940-1150°C with the strain rates of 0.01s-1 and 0.1s-1. A flow curves typically controlled by dynamic recovery were observed in the temperature range of 1090-1150 °C for the strain rate of 0.01s-1 , while discontinuous yield phenomena was found for the strain rate of 0.1s-1. The dynamic recovery can be identified by the microstructure characteristics of the deformation specimens. At 1060°C, the temperature of beta transus, the flow curves and microstructure exhibited the same deformation charateristics as that above the beta transus. At the subtransus temperature, a long period of flow softening followed by the steady-state flow can be observed. During the hot deformation, the hard phases α2 and O elongated, subboundary produced followed by cusp formation in the elongated α2 and O phases, the equiaxed morphology phases occurred by B2 phase penetrating along the subboundaries. The softening mechanism was discussed.

Interfacial Friction of Ceramics at High Temperature Ring-Compression Test

2011 ◽  
Vol 704-705 ◽  
pp. 967-972
Author(s):  
Hui Gai Wang ◽  
Yan Pei Song ◽  
Fei Wang ◽  
Kai Feng Zhang
Keyword(s):  
High Temperature ◽  
Boron Nitride ◽  
Friction Factor ◽  
Compression Test ◽  
Elevated Temperatures ◽  
Interfacial Friction ◽  
Average Pressure ◽  
Compression Tests ◽  
Ring Compression Test ◽  
Ring Compression

Using ring compression tests, the interfacial friction and flow stress of 3Y-TZP/Al2O3 composite at elevated temperatures were investigated. Theoretical calibration curves of the friction factor and the relative average pressure curves for the ring compression tests of 6:3:2 standard rings were drawn based on a velocity field capable of describing the bulge phenomena. The lubricant was the boron nitride (hexagonal). The tests were adopted at temperature range of 1400°C-1600°C. Results indicate that the interfacial friction factor has the value in the range of 0.34-0.49, so that boron nitride lubricant can be used effectively in present temperatures. As two extremely important parameters, the temperature and strain rate have no significant effect on the fraction factor. It is proved reliable that the ring-compression test at 1400°C and even higher is used to evaluate the performance of boron nitride lubricant.

Hot deformation behavior of low carbon advanced high strength steel (AHSS) microalloyed with boron

2009 ◽  
Vol 1243 ◽  
Author(s):  
I. Mejía ◽  
S. González-Sala ◽  
J.M. Cabrera
Keyword(s):  
High Temperature ◽  
Deformation Behavior ◽  
True Strain ◽  
High Strength ◽  
Tensile Tests ◽  
Strain Rates ◽  
Low Carbon ◽  
Compression Tests ◽  
Advanced High Strength Steel ◽  
Different Temperatures

ABSTRACTThis research work deals the influence of boron content on the high temperature deformation behavior of a low carbon advanced high strength steel (AHSS). For this purpose high temperature tensile and compression tests are carried out at different temperatures and constant true strain rates by using an Instron testing machine equipped with a radiant cylindrical furnace. Tensile tests are carried out at different temperatures (650, 750, 800, 900 and 1000°C) at a constant true strain rate of 0.001 s-1. Uniaxial hot compression tests are also performed over a wide range of temperatures (950, 1000, 1050 and 1100°C) and constant true strain rates (10-3, 10-2 and 10-1 s-1). In general, experimental results of hot tensile tests show an improvement of the hot ductility of the AHSS microalloyed with boron, although poor ductility at low temperatures (650 and 750°C). The fracture surfaces of the AHSS tested at temperatures showing the higher ductility (800, 900 and 1000°C) indicate that the fracture mode is a result of ductile failure, whereas in the region of poor ductility the fracture mode is of the ductile-brittle type failure. On the other hand, experimental results of hot compression tests show that both peak stress and peak strain tend to decrease in the AHSS microalloyed with boron, which indicates that boron generates a sort of solid solution softening effect in similar a way to other interstitial alloying elements in steel. Likewise, hot flow curves of the AHSS microalloyed with boron show an acceleration of the onset of dynamic recrystallization (DRX) and a delay of the recrystallization kinetics. Results are discussed in terms of boron segregation towards austenitic grain boundaries and second phase particles precipitation during plastic deformation and cooling.

A Theoretical and Experimental Study on the Dynamic Constitutive Model of Aluminum Foams

2010 ◽  
Vol 638-642 ◽  
pp. 1878-1883
Author(s):  
Ji Lin Yu ◽  
Er Heng Wang ◽  
Liu Wei Guo
Keyword(s):  
Experimental Study ◽  
Material Parameter ◽  
Aluminum Foam ◽  
Extended Model ◽  
Strain Rates ◽  
Compression Tests ◽  
Dynamic Tests ◽  
Aluminum Foams ◽  
Open Cell ◽  
Dynamic Experiments

The phenomenological constitutive framework for compressible elasto-plastic solids presented by Chen and Lu [1] is extended to the dynamic cases by assuming that the material parameter curves in the stress potential depend also on the strain rate. To check the applicability of the extended model, three types of dynamic experiments, i.e., uniaxial compression, lateral-constrained compression and side-constrained compression tests, are conducted for an open-cell aluminum foam at different strain rates. The first two types of dynamic tests are used as characteristic tests to determine the material parameter curves at different strain rates which are then used to construct the stress potential function in the model. The results show that the stress-strain curves under side-constrained compression predicted by the model are in agreement with those obtained experimentally.

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