Manufacturing Aspects Relating to the Effects of Direct Current on the Tensile Properties of Metals

2007 ◽  
Vol 129 (2) ◽  
pp. 342-347 ◽  
Author(s):  
Carl D. Ross ◽  
David B. Irvin ◽  
John T. Roth
Keyword(s):  
Strain Rate ◽  
Tensile Properties ◽  
Elevated Temperatures ◽  
Cold Work ◽  
Electrical Current ◽  
Deformation Energy ◽  
Strain Behavior ◽  
Metallic Specimen ◽  
Current Flows ◽  
Process Energy

For metals, deformation is commonly conducted at elevated temperatures, reducing the overall process energy and cost. However, elevating the temperature has many drawbacks, including high tool/die adhesions, environmental reactivity, etc. Therefore, this study examines using an electrical current to reduce the deformation energy and presents electricity’s effects on the tensile properties of various materials. The influences of strain rate and cold work are also investigated. The results demonstrate that, when current flows through a metallic specimen, the material’s yield strength, flow stress, and elastic modulus are decreased; strain weakening occurs; and the total energy of deformation is decreased. These changes in the engineering stress-strain behavior occurred in all of the materials tested and are much greater than can be accounted for by resistive heating. However, the effects diminish with increasing strain rate. The analysis shows that applying electricity during deformation provides a viable alternative to increasing the workpiece temperature for deformation-based manufacturing processes.

The Effects of DC Current on the Tensile Properties of Metals

Materials ◽  
2005 ◽  
Author(s):  
Carl Ross ◽  
John T. Roth
Keyword(s):  
Tensile Properties ◽  
Cold Work ◽  
Electrical Current ◽  
Deformation Energy ◽  
Strain Rates ◽  
Negative Effects ◽  
Alternative Means ◽  
Metallic Specimen ◽  
Current Flows ◽  
Dc Current

When fabricating parts, deformation is commonly conducted in a “warm” or “hot” state in order to reduce the total energy required to form the metal. However, there are several negative effects associated with this method of energy reduction (e.g., high tool/die adhesions, environmental reactivity, etc.) Hence, another more efficient method of reducing the total deformation energy would be very beneficial. This paper examines an alternative means of reducing the energy by applying an electrical current and also determines how the material’s tensile properties are affected while the current is present. Also investigated are the influences of strain rate and cold work on the electrical effects. The stress-strain curves indicate that, when current flows through a metallic specimen, the energy required to cause deformation is greatly decreased; demonstrating that electricity provides a viable alternative to increasing the workpiece temperature. However, the effect of the electricity diminishes with increasing strain rates.

AISI TYPE A9

Alloy Digest ◽  
1994 ◽  
Vol 43 (9) ◽  
Keyword(s):  
Physical Properties ◽  
Tensile Properties ◽  
Tool Steel ◽  
High Resistance ◽  
Elevated Temperatures ◽  
Cold Work ◽  
Heat Treating ◽  
Steel Mills ◽  
Aisi Type ◽  
Cold Work Tool Steel

Abstract A9 is a medium-alloy, air-hardening type cold work tool steel. It exhibits a high resistance to softening at elevated temperatures. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on heat treating and machining. Filing Code: TS-531. Producer or source: Tool steel mills.

Effect of Electrical Current on Cold Work in Aluminum 2024

2017 ◽  
Author(s):  
Derek Shaffer ◽  
Sean Sehman ◽  
Ihab Ragai ◽  
John T. Roth ◽  
Bin Wang
Keyword(s):  
Heat Treatment ◽  
Residual Stresses ◽  
Tensile Properties ◽  
Current Density ◽  
Material Properties ◽  
Cold Work ◽  
Electrical Current ◽  
Material Microstructure ◽  
Expected Effect ◽  
The Difference

Many manufacturers are looking towards electrical treatments as methods for reducing residual stresses in formed metals. Although many people have investigated the effects electricity has on residual stresses and plasticity, there has not been research investigating the effects it has as a post-treatment on strain hardening. Therefore, the goal of this research is to show the permanent changes in tensile properties that electrical treatments have on strain hardened metals, specifically Aluminum 2024. For this initial investigation, only one pulse duration and current density was used to categorize any changes in the metals due to applying electric current. This testing shows the difference between post-deformation heat treatments and post-deformation electrical treatments. Tensile properties of Aluminum 2024 were used to gauge the changes caused by the treatments. The heat treatment had the expected effect of lower the strength of the material and regrowing the grains while the electrical treatment did not seem to drastically change the structure of the grains, but still lowered the strength of the material. Microstructure investigations also showed that the material does in fact show slight changes in material properties, but no drastic changes in microstructure. These images also show that the regrowth from the heat treatment is clearly the reason for the decrease in strength.

scholarly journals High Strain Rate Tensile Properties of Annealed 2 1/4 Cr-1 Mo Steel

1976 ◽  
Vol 98 (4) ◽  
pp. 361-368 ◽  
Author(s):  
R. L. Klueh ◽  
R. E. Oakes
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
High Strain Rate ◽  
Strain Rate ◽  
Tensile Properties ◽  
Elevated Temperatures ◽  
High Strain ◽  
Total Elongation ◽  
Major Effect ◽  
Dynamic Strain

The high strain rate tensile properties of annealed 2 1/4 Cr-1 Mo steel were determined and the tensile behavior from 25 to 566°C and strain rates of 2.67 × 10−6 to 144/s were described. Above 0.1/s at 25°C, both the yield stress and the ultimate tensile strength increased rapidly with increasing strain rate. As the temperature was increased, a dynamic strain aging peak appeared in the ultimate tensile strength-temperature curves. The peak height was a maximum at about 350°C and 2.67 × 10−6/s. With increasing strain rate, a peak of decreased height occurred at progressively higher temperatures. The major effect of strain rate on ductility occurred at elevated temperatures, where a decrease in strain rate caused an increase in total elongation and reduction in area.

The Reduction of Deformation Energy and Increase in Workability of Metals Through an Applied Electric Current

2005 ◽  
Author(s):  
Timothy A. Perkins ◽  
John T. Roth
Keyword(s):  
Strain Rate ◽  
Electric Current ◽  
Sheet Metal ◽  
Specific Energy ◽  
Material Properties ◽  
Elastic Recovery ◽  
Electrical Current ◽  
Deformation Energy ◽  
Manufacturing Processes ◽  
Open Die Forging

Many manufacturing processes (e.g., forging, rolling, extrusion, and sheet metal) rely on the application of heat to reduce the forces associated with fabricating parts. However, due to the negative implications associated with hot working, another more efficient means of applying energy is desired. This paper investigates the changes in the material properties of various metals (aluminum, copper, iron, and titanium based alloys) in response to electricity flow. Theory involving electromigration, and, more specifically, electroplasticity, is examined and the implications thereof are analyzed. It is shown that, using electrical current, the flow stresses in a material are reduced, resulting in a lower specific energy for open-die forging. It is also shown that an applied electrical current can increase the forgeability of materials, allowing greater deformation prior to cracking. Additionally, elastic recovery is shown to decrease when using electricity during deformation. Finally, For most materials, these effects were dependent on strain rate.

Ultimate Tensile Properties of Elastomers. I. Characterization by a Time and Temperature Independent Failure Envelope

1964 ◽  
Vol 37 (4) ◽  
pp. 777-791 ◽  
Author(s):  
Thor L. Smith
Keyword(s):  
Strain Rate ◽  
Tensile Properties ◽  
Elevated Temperatures ◽  
Constant Strain Rate ◽  
Test Methods ◽  
Constant Stress ◽  
Test Method ◽  
Failure Envelope ◽  
Polymeric Network ◽  
Time To Rupture

Abstract The tensile stress at break (σb) and the associated ultimate strain (εb) of an elastomer depend on (1) the chemical and topological characteristics of the polymeric network, and (2) the test conditions under which rupture is observed. To separate these effects, the ultimate tensile properties can often be characterized by a “failure envelope” defined by values of σb and εb determined at various strain rates over a wide temperature range. Provided time—temperature superposition is applicable, such data superpose on a plot of log σbT0/T versus log εb, where T is the test temperature (absolute) and T0 is an arbitrarily selected reference temperature. The resulting failure envelope is independent of time (strain rate) and temperature and thus it depends only on basic characteristics of the polymeric network. To illustrate the characterization method, data on two styrene-butadiene gum vulcanizates, SBR-I and SBR-II, were analyzed. For SBR-I, values of σb and εb obtained over extensive ranges of strain rate and temperature superposed to give a failure envelope. Data at elevated temperatures also gave a reliable value for the equilibrium modulus. For SBR-II, data obtained at various temperatures under conditions of constant strain and constant strain rate yielded identical failure envelopes; this strongly suggests that the failure envelope is independent of the test method. A theoretical consideration of the time-to-rupture associated with different test methods showed that for given values of σb and εb the time-to-rupture from the following types of tests should increase in the order: constant strain < constant stress < constant strain rate < constant stress rate.

Tensile Properties of MoSi2 at Elevated Temperatures

2004 ◽  
Vol 449-452 ◽  
pp. 845-848 ◽  
Author(s):  
Ai Dang Shan ◽  
Jian Sheng Wu ◽  
Hitoshi Hashimoto ◽  
Yong Ho Park
Keyword(s):  
Activation Energy ◽  
Grain Size ◽  
Strain Rate ◽  
Tensile Properties ◽  
Elevated Temperatures ◽  
Strain Rate Range ◽  
Rate Range ◽  
Energy Value ◽  
Lower Strain ◽  
Ductility Maximum

The tensile properties of two MoSi2 alloys with different grain sizes (1 micrometer and 10 micrometer) were evaluated in vacuum at temperatures ranging from 1400 to 1600K and initial strain rates ranging from 1×10-5/s to 1×10-3/s. For the alloy with 10micron grain size an m vale of 0.35 and an activation energy value of 350 kJ/mol were observed in the lower strain rate range while an m value of 0.12 and an activation energy value of 760 kJ/mol were observed in the higher strain rate range. For the alloy with 1micron grain size, a uniform m value of 0.55 and an activation energy value of 160 kJ/mol were observed. Moreover these two alloys showed remarkable ductility (maximum 33%) in the test temperatures. The deformation mechanism and the remarkable ductility are discussed in the light of the microstructural observations through SEM and TEM.

Effect Of Elevated Temperatures On Complete Concrete Deformation Diagrams

2019 ◽  
pp. 9-14
Keyword(s):  
Experimental Data ◽  
Elastic Modulus ◽  
Elevated Temperatures ◽  
Peak Load ◽  
Relative Deformation ◽  
Deformation Characteristics ◽  
Compression Tests ◽  
Strain Behavior ◽  
Different Temperatures ◽  
Deformation Diagrams

The analysis of the previous results of the study on concrete stress-strain behavior at elevated temperatures has been carried out. Based on the analysis, the main reasons for strength retrogression and elastic modulus reduction of concrete have been identified. Despite a significant amount of research in this area, there is a large spread in experimental data received, both as a result of compression and tension. In addition, the deformation characteristics of concrete are insufficiently studied: the coefficient of transverse deformation, the limiting relative compression deformation corresponding to the peak load and the almost complete absence of studies of complete deformation diagrams at elevated temperatures. The two testing chambers provided creating the necessary temperature conditions for conducting studies under bending compression and tension have been developed. On the basis of the obtained experimental data of physical and mechanical characteristics of concrete at different temperatures under conditions of axial compression and tensile bending, conclusions about the nature of changes in strength and deformation characteristics have been drawn. Compression tests conducted following the method of concrete deformation complete curves provided obtaining diagrams not only at normal temperature, but also at elevated temperature. Based on the experimental results, dependences of changes in prism strength and elastic modulus as well as an equation for determining the relative deformation and stresses at elevated temperatures at all stages of concrete deterioration have been suggested.

UDIMET 520

Alloy Digest ◽  
1962 ◽  
Vol 11 (9) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
Elevated Temperatures ◽  
Base Alloy ◽  
High Strength ◽  
Heat Treating ◽  
Nickel Base Alloy ◽  
Nickel Base

Abstract UDIMET 520 is a nickel-base alloy recommended for applications where high strength at elevated temperatures is required. It is suitable for service at temperatures up to 1800 F. This datasheet provides information on composition, physical properties, and tensile properties as well as creep. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-74. Producer or source: Special Metals Inc..

ALCOA 351 SUPRACAST

Alloy Digest ◽  
2020 ◽  
Vol 69 (7) ◽  
Keyword(s):  
Physical Properties ◽  
Tensile Properties ◽  
Copper Alloy ◽  
High Performance ◽  
Elevated Temperatures ◽  
Heat Treating ◽  
Aluminum Silicon

Abstract Alcoa 351 SupraCast is a heat-treatable aluminum-silicon-copper alloy that also contains small amounts of magnesium, manganese, vanadium, and zirconium. It is designed for components exposed to elevated temperatures in high performance engines. This datasheet provides information on composition, physical properties, and tensile properties as well as fatigue. It also includes information on heat treating, machining, and joining. Filing Code: Al-466. Producer or source: Alcoa Corporation.

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