1-20 of 48 Search Results for

superplastic flow

Follow your search
Access your saved searches in your account

Would you like to receive an alert when new items match your search?
Close Modal
Sort by
Series: ASM Handbook
Volume: 4E
Publisher: ASM International
Published: 01 June 2016
DOI: 10.31399/asm.hb.v04e.a0006282
EISBN: 978-1-62708-169-6
... reductions of yield loss and machining costs. Rate of strain, temperature, and grain size are the major factors that influence the superplasticity of titanium alloys. Strain-rate sensitivity, m , is defined as: m ≈ Δ ( log σ ) Δ ( log ε ˙ ) where σ is flow stress, and is...
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005433
EISBN: 978-1-62708-196-2
... and classical physical constitutive equations. The article also reviews the accommodation mechanisms that are divided into two major groups, namely, diffusional accommodation and accommodation by dislocations. constitutive model superplastic flow superplasticity phenomenological constitutive...
Series: ASM Handbook
Volume: 14A
Publisher: ASM International
Published: 01 January 2005
DOI: 10.31399/asm.hb.v14a.a0004020
EISBN: 978-1-62708-185-6
..., followed by the models of constitutive behavior. It provides a discussion on creep mechanisms involving dislocation and diffusional flow, such as the Nabarro-Herring creep and the Coble creep. The equations for the several creep rates are also presented. Research on the mechanism of the superplastic flow...
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005458
EISBN: 978-1-62708-196-2
..., cavity-growth models were developed; these analyses focused on stress concentrations along the grain boundaries, with diffusional flow relaxing tensile stresses at cavity tips on the grain boundary and higher tensile stresses developing in regions between cavities. This leads to higher vacancy...
Series: ASM Handbook
Volume: 14A
Publisher: ASM International
Published: 01 January 2005
DOI: 10.31399/asm.hb.v14a.a0004010
EISBN: 978-1-62708-185-6
...) Utilizing opposing rollers Aluminum alloys can be readily processed by roll forming at room temperature. Aluminum alloys have relatively low flow stresses, but they exhibit work hardening during roll forming. Table 1 lists strain-hardening exponents and strength coefficients for aluminum and...
Series: ASM Desk Editions
Publisher: ASM International
Published: 01 December 1998
DOI: 10.31399/asm.hb.mhde2.a0003177
EISBN: 978-1-62708-199-3
... workpiece (chemical surface activity) 4 3 2 1 Flushing action to prevent buildup of scale and dirt (fluid flow) 5 4 3 2 Protect surface characteristics; nonstaining 5 2 2 1 Minimize processing costs, welding, cleaning, and painting 5 2 2 1 Minimize environmental effect, air...
Series: ASM Handbook
Volume: 14A
Publisher: ASM International
Published: 01 January 2005
DOI: 10.31399/asm.hb.v14a.a0009011
EISBN: 978-1-62708-185-6
... Abstract This article discusses the equipment design, procedures, experimental considerations, and interpretation of the torsion tests used to establish workability. It describes the application of torsion testing to obtain flow-stress data and to gage fracture-controlled workability and flow...
Series: ASM Handbook
Volume: 14A
Publisher: ASM International
Published: 01 January 2005
DOI: 10.31399/asm.hb.v14a.a0009010
EISBN: 978-1-62708-185-6
...-6Al-4V) alloy. Source: Ref 37 An important requirement for cavitation during flow under either hot-working or superplastic conditions is the presence of a tensile stress. On the other hand, under conditions of homogeneous compression, cavitation is not observed; in fact, cavities that may be...
Series: ASM Handbook
Volume: 14A
Publisher: ASM International
Published: 01 January 2005
DOI: 10.31399/asm.hb.v14a.a0004025
EISBN: 978-1-62708-185-6
... Abstract The material data for forging can be divided into two categories, namely, mechanical properties and thermophysical properties. This article describes the flow characteristics of key engineering materials, such as steels, aluminum alloys, copper alloys, titanium alloys, and nickel-base...
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005409
EISBN: 978-1-62708-196-2
... in such situations are enhanced by approximately an order of magnitude relative to those for static coarsening. The effect is most noticeable at strain rates that characterize superplastic (or near-superplastic) flow, that is, ∼10 −4 to 10 −3 s −1 . Under these conditions, the time of deformation...
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005421
EISBN: 978-1-62708-196-2
... interface; σ is the applied stress. This criterion implies that flow hardening is required to continuously nucleate and grow cavities, which usually does not occur during conventional hot working or superplastic flow (except in cases of significant grain growth). The equation also leads to required stresses...
Series: ASM Handbook
Volume: 14A
Publisher: ASM International
Published: 01 January 2005
DOI: 10.31399/asm.hb.v14a.a0009012
EISBN: 978-1-62708-185-6
... variables are flow stress, σ o , and strain to failure, ε f . Basically, σ o is a measure of the resistance of a material to deformation, and ε f is a measure of the deformation limits of a material. The capabilities of various hot working simulation tests are summarized in Table 1 ( Ref 1...
Series: ASM Handbook
Volume: 14A
Publisher: ASM International
Published: 01 January 2005
DOI: 10.31399/asm.hb.v14a.a0003985
EISBN: 978-1-62708-185-6
... superplastic behavior has been observed in IN 100 at working temperatures as low as 925 °C (1700 °F), the optimal isothermal forge temperature range falls between 1040 and 1150 °C (1900 and 2100 °F) when strain rates of 0.001 to 0.1 mm/mm/s are typically used. Figure 7 shows the flow stress for IN 100 when...
Series: ASM Handbook
Volume: 14A
Publisher: ASM International
Published: 01 January 2005
DOI: 10.31399/asm.hb.v14a.a0003999
EISBN: 978-1-62708-185-6
... of precipitates. In this condition, the material exhibits superplastic properties that are characterized by large tensile elongations, good die-filling capacity, and relatively low flow stress. Superplastic nickel-base materials exhibit a large strain-rate sensitivity that provides the mechanism for...
Series: ASM Handbook
Volume: 14A
Publisher: ASM International
Published: 01 January 2005
DOI: 10.31399/asm.hb.v14a.a0003993
EISBN: 978-1-62708-185-6
... article “Dies and Die Materials for Hot Forging” in this Volume). Deformation mechanisms during hot working include microstructural processes such as: Dynamic recrystallization (DRX) Superplastic deformation Dynamic recovery Void formation Flow instability processes (such...
Series: ASM Handbook
Volume: 14A
Publisher: ASM International
Published: 01 January 2005
DOI: 10.31399/asm.hb.v14a.a0004016
EISBN: 978-1-62708-185-6
... effects attained with different deformation techniques. For large strains when the material strengthening ability is exhausted, plastic flow becomes unstable and localized inside shear bands (SBs). Very thin shear bands first appear at the microscale, then they join into clusters observed at the...
Series: ASM Handbook
Volume: 14A
Publisher: ASM International
Published: 01 January 2005
DOI: 10.31399/asm.hb.v14a.a0004001
EISBN: 978-1-62708-185-6
... resistance and reduced flow stresses. These improvements are useful in secondary processes such as sheet rolling, superplastic forming of sheet, and isothermal, closed-die forging. Two major techniques for rolling of sheet have evolved from the early work on near-isothermal, hot pack rolling conducted by...
Series: ASM Handbook
Volume: 14A
Publisher: ASM International
Published: 01 January 2005
DOI: 10.31399/asm.hb.v14a.a0004007
EISBN: 978-1-62708-185-6
... order of flow stress of the material in order to inhibit/eliminate void formation ( Ref 25 , Ref 26 , Ref 27 ). Pressure-induced void inhibition in this case increases the ability to form superplastically in addition to positively impacting properties of the superplastically formed material. While...
Series: ASM Handbook
Volume: 14A
Publisher: ASM International
Published: 01 January 2005
DOI: 10.31399/asm.hb.v14a.a0009013
EISBN: 978-1-62708-185-6
... is the density. Therefore, materials with the highest diffusivity have high conductivity and low heat capacity and density. During metalworking, the thermal conductivity of both the workpiece and the tooling can be important. Two common methods for measuring these properties are the heat flow meter...
Series: ASM Desk Editions
Publisher: ASM International
Published: 01 December 1998
DOI: 10.31399/asm.hb.mhde2.a0003181
EISBN: 978-1-62708-199-3
... operation. Therefore, the amount of springback for this alloy must be computed from the 520 MPa (75 ksi) flow stress, rather than from the initial value of the yield strength. Most cold-forming operations require the use of annealed material. However, the softer alloys, such as Nickel 200, the NILO...