Cavitation in a Uniaxially deformed Superplastic Al-Mg Alloy

1999 ◽  
Vol 601 ◽  
Author(s):  
D. H. Bae ◽  
A. K. Ghosh
Keyword(s):  
Strain Rate ◽  
Volume Fraction ◽  
Cavity Growth ◽  
Tensile Tests ◽  
Strain Rate Range ◽  
Cavity Volume ◽  
Fine Grained ◽  
Cu Alloy ◽  
Deformable Particles ◽  
The Matrix

AbstractCavitation caused by superplastic straining of a fine-grained Al-Mg-Mn-Cu alloy under uniaxial tension has been systematically evaluated. Tensile tests were conducted in the strain-rate range of 10−4s−1 to 10−2s−1 and in the temperature range of 450°C to 550°C. Measurements of the number and size of cavities were made by image analysis through optical microscopy on tested specimens. With increasing imposed strain, the cavity population density increases. Cavity growth has been found to be primarily due to the plastic deformation of the matrix. These results are characterized by the total volume fraction of cavities which is found to increase exponentially with strain. However, the dependencies of cavity volume fraction on strain-rate and temperature are not straightforward and the notion of just a few large cavities controlling the total cavity volume is not always true. Attempts to explain these complex dependencies have been carried out based on the concepts of debonding between the matrix and non-deformable particles, the continuous nucleation of new cavities, and plasticity-based cavity growth for large cavities.

Strain Rate Effects on Tensile Properties of Fiber Reinforced Concrete

1985 ◽  
Vol 64 ◽  
Author(s):  
George G. Nammur ◽  
Antoine E. Naaman
Keyword(s):  
Reinforced Concrete ◽  
Strain Rate ◽  
Volume Fraction ◽  
Tensile Tests ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Strain Rate Effects ◽  
Rate Effects ◽  
The Matrix

ABSTRACTHigh strain rates lead to substantial modifications in the stress-strain (or stress-displacement) response of fiber reinforced concrete in tension. These modifications include higher strength and corresponding strain, as well as smaller displacement at failure.The purpose of this paper is to investigate the behavior of fiber reinforced concrete under impact tensile loading, and to study the effect of strain rate on the post-cracking strength of the composite. The variation of the tensile strength of the matrix with the reinforcement parameters such as volume fraction Vf and aspect ratio |/φ of the fibers is also studied ip this paper. A special emphasis is placed on the stress-displacement relationship of steel fiber reinforced concrete in its post-cracking range. An empirical model of the stress- displacement relationship as a function of the strain rate is developed from experimental data from tensile tests on dogbone shape notched tensile prisms. The model highlights the effects of strain rate and fiber properties on the post-cracking strength of the composite, as well as the displacement at failure. The effect of strain rate on the post-cracking toughness of fiber reinforced concrete is also addressed. The literature on impact effects on concrete in tension (plain and fiber reinforced) is briefly reviewed in this paper, and so is the state of the art of testing techniques for strain rate effects.

An Investigation of Cavity Growth Rate in Superplastic Al and Mg Alloys

2005 ◽  
Vol 475-479 ◽  
pp. 2945-2948 ◽  
Author(s):  
Mamoru Mabuchi ◽  
Yasumasa Chino ◽  
Hajime Iwasaki
Keyword(s):  
Growth Rate ◽  
Volume Fraction ◽  
Cavity Growth ◽  
Mg Alloy ◽  
Al Alloy ◽  
Cavity Volume ◽  
Superplastic Behavior ◽  
Fine Grained ◽  
Cavity Growth Rate ◽  
5083 Al Alloy

Fine-grained 5083 Al alloy and AZ91 Mg alloy showed superplastic behavior. The plasticitycontrolled growth rates of cavities during superplastic deformation for the Al alloy and Mg alloy were investigated. The cavity volume fraction for the Mg alloy was larger than that for the Al alloy. However, the cavity growth rate for the Mg alloy was lower than that for the Al alloy.

scholarly journals A High-Strain-Rate Superplasticity of the Al-Mg-Si-Zr-Sc Alloy with Ni Addition

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2028
Author(s):  
Andrey Mochugovskiy ◽  
Anton Kotov ◽  
Majid Esmaeili Ghayoumabadi ◽  
Olga Yakovtseva ◽  
Anastasia Mikhaylovskaya
Keyword(s):  
Strain Rate ◽  
Volume Fraction ◽  
Strain Rate Range ◽  
Zener Pinning ◽  
Nucleation Effect ◽  
Pinning Effect ◽  
Ni Addition ◽  
Elongation To Failure ◽  
Mean Size ◽  
High Temperature Tensile

The current study analyzed the effect of Ni content on the microstructure and superplastic deformation behavior of the Al-Mg-Si-Cu-based alloy doped with small additions of Sc and Zr. The superplasticity was observed in the studied alloys due to a bimodal particle size distribution. The coarse particles of eutectic origin Al3Ni and Mg2Si phases with a total volume fraction of 4.0–8.0% and a mean size of 1.4–1.6 µm provided the particles with a stimulated nucleation effect. The L12– structured nanoscale dispersoids of Sc- and Zr-bearing phase inhibited recrystallization and grain growth due to a strong Zener pinning effect. The positive effect of Ni on the superplasticity was revealed and confirmed by a high-temperature tensile test in a wide strain rate and temperature limits. In the alloy with 4 wt.% Ni, the elongation-to-failure of 350–520% was observed at 460 °C, in a strain rate range of 2 × 10−3–5 × 10−2 s−1.

Shape Memory Characteristics and Superelasticity of Ti-Ni-Cu Alloy Ribbons with Nano Ti2Ni Particles

2008 ◽  
Vol 8 (2) ◽  
pp. 722-727 ◽  
Author(s):  
Tae-hyun Nam ◽  
Cheol-am Yu ◽  
Jung-min Nam ◽  
Hyun-gon Kim ◽  
Yeon-wook Kim
Keyword(s):  
Melt Spinning ◽  
Volume Fraction ◽  
Deformation Behaviour ◽  
Parent Phase ◽  
Tensile Tests ◽  
Constant Load ◽  
Cu Alloy ◽  
Transmission Electron ◽  
Average Size ◽  
Memory Characteristics

Microstructures and deformation behaviour of Ti-45Ni-5Cu and Ti-46Ni-5Cu alloy ribbons prepared by melt spinning were investigated by transmission electron microscopy, thermal cycling tests under constant load and tensile tests. Spherical Ti2Ni particles coherent with the B2 parent phase were observed in the alloy ribbons when the melt spinning temperature was higher than 1773 K. Average size of Ti2Ni particles in the ribbons obtained at 1873 K was 8 nm, which was smaller than that (10 nm) in the ribbons obtained at 1773 K. Volume fraction of Ti2Ni phase in the ribbons obtained at 1873 K was 40%, which was larger than that (20%) in the ribbons obtained at 1773 K. The stress required at temperatures of Af + 10 K for the stress-induced martensitic transformation increased from 93 MPa to 229 MPa and apparent elastic modulus of the B2 parent phase increased from 56 GPa to 250 GPa with increasing the melt spinning temperature from 1673 K to 1873 K in Ti-45Ni-5Cu alloy ribbons. The critical stress for slip deformation of the ribbons increased by coherent Ti2Ni particles, and thus residual elongation did not occur even at 160 MPa, while considerable plastic deformation occurred at 60 MPa in the ribbons without Ti2Ni particles. Almost perfect superelastic recovery was found in the ribbons with coherent Ti2Ni particles, while only partial superelastic recovery was observed in the ribbons without coherent Ti2Ni particles.

Tensile Stress-Strain Curves Modeling of Four Kinds of Solders with Temperature and Rate Dependence

2005 ◽  
Vol 297-300 ◽  
pp. 905-911 ◽  
Author(s):  
Xu Chen ◽  
Li Zhang ◽  
Masao Sakane ◽  
Haruo Nose
Keyword(s):  
Tensile Stress ◽  
Constitutive Model ◽  
Strain Rate ◽  
Constant Strain Rate ◽  
Tensile Tests ◽  
Strain Rate Range ◽  
Rate Dependence ◽  
Strain Rates ◽  
Stress Strain ◽  
Rate Range

A series of tensile tests at constant strain rate were conducted on tin-lead based solders with different Sn content under wide ranges of temperatures and strain rates. It was shown that the stress-strain relationships had strong temperature- and strain rate- dependence. The parameters of Anand model for four solders were determined. The four solders were 60Sn-40Pb, 40Sn-60Pb, 10Sn-90Pb and 5Sn-95Pb. Anand constitutive model was employed to simulate the stress-strain behaviors of the solders for the temperature range from 313K to 398K and the strain rate range from 0.001%sP -1 P to 2%sP -1 P. The results showed that Anand model can adequately predict the rate- and temperature- related constitutive behaviors at all test temperatures and strain rates.

scholarly journals Hot Deformation Behavior and Microstructure Evolution of Cu–Ni–Co–Si Alloys

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2042 ◽  
Author(s):  
Feng Liu ◽  
Jimiao Ma ◽  
Lijun Peng ◽  
Guojie Huang ◽  
Wenjing Zhang ◽  
...  
Keyword(s):  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Strain Rate Range ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Hot Deformation Behavior ◽  
Deformation Activation Energy ◽  
The Matrix ◽  
Dynamic Recrystallization Behavior

The Cu-1.7Ni-1.4Co-0.65Si (wt%) alloy is hot compressed by a Gleeble-1500D machine under a temperature range of 760 to 970 °C and a strain rate range of 0.01 to 10 s−1. The flow stress increases with the extension of strain rate and decreases with the rising of deformation temperature. The dynamic recrystallization behavior happens during the hot compression deformation process. The hot deformation activation energy of the alloy can be calculated as 468.5 kJ/mol, and the high temperature deformation constitutive equation is confirmed. The hot processing map of the alloy is established on the basis of hot deformation behavior and hot working characteristics. With the optimal thermal deformation conditions of 940 to 970 °C and 0.01 to 10 s−1, the fine equiaxed grain and no holes are found in the matrix, which can provide significant guidance for hot deformation processing technology of Cu–Ni–Co–Si alloy.

Cavitation Behavior of Ultra-Fine Grained Ti-6Al-4V Alloy Produced by Equal-Channel Angular Pressing

2007 ◽  
Vol 551-552 ◽  
pp. 621-626
Author(s):  
Young Gun Ko ◽  
Yong Nam Kwon ◽  
Jung Hwan Lee ◽  
Dong Hyuk Shin ◽  
Chong Soo Lee
Keyword(s):  
Grain Size ◽  
Strain Rate ◽  
Equal Channel Angular Pressing ◽  
Cavity Growth ◽  
Rate Sensitivity ◽  
Theoretical Models ◽  
Coarse Grained ◽  
Fine Grained ◽  
Angular Pressing ◽  
Cavitation Behavior

Cavitation behavior during superplastic flow of ultra-fine grained (UFG) Ti-6Al-4V alloy was established with the variation of grain size and misorientation. After imposing an effective strainup to 8 via equal-channel angular pressing (ECAP) at 873 K, alpha-phase grains were markedly refined from 11 μm to ≈ 0.3 μm, and misorientation angle was increased. Uniaxial-tension tests were conducted for initial coarse grained (CG) and two UFG alloys (ε = 4 and 8) at temperature of 973 K and strain rate of 10-4 s-1. Quantitative measurements of cavitation evidenced that both the average size and the area fraction of cavities significantly decreased with decreasing grain size and/or increasing misorientation. It was also found that, when compared to CG alloy, cavitation as well as diffused necking was less prevalent in UFG alloys, which was presumably due to the higher value of strain-rate sensitivity. Based on the several theoretical models describing the cavity growth behavior, the cavity growth mechanism in UFG alloys was suggested.

Stress-Strain Equations for Some Near-Eutectic Tin-Lead Solders

1991 ◽  
Vol 113 (4) ◽  
pp. 475-484 ◽  
Author(s):  
K. P. Jen ◽  
J. N. Majerus
Keyword(s):  
Strain Rate ◽  
Printed Circuit Boards ◽  
Volume Fraction ◽  
Total Error ◽  
Tensile Tests ◽  
Elastic Behavior ◽  
Plastic Behavior ◽  
Strain Rates ◽  
Stress Strain ◽  
Engineering Strain

This paper presents the evaluation of the stress-strain behavior, as a function of strain-rate, for three tin-lead solders at room temperature. This behavior is critically needed for reliability analysis of printed circuit boards (PCB) since handbooks list minimal mechanical properties for the eutectic solder used in PCBs. Furthermore, most handbook data are for stable eutectic microstructure whereas PCB solder has a metastable microstructure. All three materials were purchased as “eutectics.” However, chemical analysis, volume fraction determination, and microhardness tests show some major variations between the three materials. Two of the materials have a eutectic composition, and one does not. The true stress-strain equations of one eutectic and the one noneutectic material are determined from compressive tests at engineering strain-rates between 0.0002/s and 0.2/s. The second eutectic material is evaluated using tensile tests with strain-rates between 0.00017/s and 0.042/s. The materials appear to exhibit linear elastic behavior only at extremely small strains, i.e., less than 0.0005. However, this “elastic” behavior showed considerable variation, and depended upon the strain rate. In both tension and compression the eutectic alloy exhibits nonlinear plastic behavior, i.e., strain-softening followed by strain-hardening, which depends upon the strain rate. A quadratic equation σy = σy(ε˚/ε˚0) + A(ε˚/ε˚0)ε + B(ε˚/ε˚0)ε2 fit to the data gives correlation coefficients R2 > 0.91. The coefficients σy(ε˚/ε˚0), A(ε˚/ε˚0), B(ε˚/ε˚0) are fitted functions of the normalized engineering strain rate ε˚/ε˚0. Replicated experiments are used at each strain-rate so that a measure of the statistical variation could be estimated. Measures of error associated with the regression analysis are also obtained so that an estimate of the total error in the stress-strain relations can be made.

Effect of Carbon Nanofiber on Thermal and Tensile Properties of Polypropylene

2006 ◽  
Author(s):  
Yuanxin Zhou ◽  
Mohammad Monirul Hasan ◽  
Shaik Jeelani
Keyword(s):  
Thermal Properties ◽  
Yield Strength ◽  
Strain Rate ◽  
Carbon Nanofiber ◽  
Tensile Modulus ◽  
Tensile Tests ◽  
Strain Rate Range ◽  
Mechanical And Thermal Properties ◽  
Single Filament ◽  
Polypropylene Powder

In the present study, effect of vapor grown carbon nanofiber on the mechanical and thermal properties of polypropylene was investigated. Firstly, nanofibers were dry-mixed with polypropylene powder and extruded into filaments by using a single screw extruder. Then the tensile tests were performed on the single filament at the strain rate range from 0.02/min to 2/min. Experiments results show that both neat and nano-phased polypropylene were strain rate strengthening material. The tensile modulus and yield strength both increased with increasing strain rate. Experimental results also show that infusing nanofiber into polypropylene can increase tensile modulus and yield strength, but decrease the failure strain. At the same time, thermal properties of neat and nano-phased polypropylene were characterized by TGA. TGA results have showed that the nanophased system is more thermally stable. At last, a nonlinear constitutive equation has been developed to describe strain rate sensitive behavior of neat and nano-phased polypropylene.

Plastic Flow Instabilities of L12 Ni3(Si,Ti) Alloys at Intermediate Temperature

2002 ◽  
Vol 17 (3) ◽  
pp. 705-711 ◽  
Author(s):  
H. Honjo ◽  
Y. Kaneno ◽  
H. Inoue ◽  
T. Takasugi
Keyword(s):  
Strain Rate ◽  
Plastic Flow ◽  
Flow Behavior ◽  
Rate Sensitivity ◽  
Tensile Tests ◽  
Lattice Diffusion ◽  
Intermediate Temperature ◽  
Fine Grained ◽  
Ti Alloys ◽  
Temperature Strain

The serrated plastic flow of L12 Ni3 (Si,Ti) alloys at intermediate temperature was investigated by tensile tests in terms of the effects of temperature, strain rate, composition, and microstructure. Serrated plastic flow was most strongly observed at 473 K and at a strain rate of 1.6 × 10–4 s–1. Correspondingly, the maximum stress amplitude and the lowest (negative) strain-rate sensitivity were observed at 473 K. Serrated plastic flow took place irrespective of boron doping and was more significant in a fine-grained Ni3 (Si,Ti) alloy. The static aging at 473 K resulted in reduced flow stress. The activation energy for serrated plastic flow was estimated to be about 57 kJ mol–1, suggestive of being smaller than that for lattice diffusion of solutes. The serrated plastic flow behavior of Ni3 (Si,Ti) alloys was compared with that of L12 Co3Ti alloys, and is qualitatively explained on the basis of the dynamics of solutes in the core of a dissociated screw dislocation.

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