A mechanical interpretation of the activation energy of high temperature deformation in two phase materials

Briottet, Laurent; Jonas, John J.; Montheillet, F.

doi:10.1016/1359-6454(95)00257-x

Cited by 123 publications

(64 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…An activation energy of 430 kJ mol -1 for hot-working of solutiontreated IN718 (Type I microstructure) is in good agreement with values derived for the same material in the literature, 390-440 kJ mol -1 [8][9][10][11]. Higher values of Q for the Type II and Type III materials, as listed in Table 2, can be attributed to the presence of d precipitates; second-phase particles are known to affect the measured hot-working activation energy in steels [22] and two-phase titanium alloys [23].…”

Section: Deformation Behaviorsupporting

confidence: 77%

Hot Forging of IN718 with Solution-Treated and Delta-Containing Initial Microstructures

Lalvani

Brooks

2016

Metallogr. Microstruct. Anal.

View full text Add to dashboard Cite

A systematic study of the effect of d phase precipitate morphology on the hot deformation behavior and microstructural evolution in nickel superalloy Inconel 718 is presented. Isothermal compression tests at fixed nominal strain rates and temperatures relevant to industrial forging (0.001-0.3 s -1 and 990-1040°C) were used. Three distinct initial microstructures have been examined: (I) solution treated, (II) a microstructure with finely dispersed particulate d precipitates, and (III) a microstructure containing dense network of intragranular and grain boundary d platelets. The peak flow stress associated with these various microstructures has been rationalized using a single, temperature-compensated power law. This clearly demonstrates opposition of the external applied stress by an internal back stress related to the initial d phase morphology and apparent delta solvus temperature. Post-peak flow softening is attributed to dynamic recrystallization, aided by the dissolution of finer precipitates in material containing particulate d phase, and to a certain degree of mechanical grain refinement caused by distortion and offsetting of grain segments where a dense d-platelet structure exists.

show abstract

Section: Deformation Behaviorsupporting

confidence: 77%

Hot Forging of IN718 with Solution-Treated and Delta-Containing Initial Microstructures

Lalvani

Brooks

2016

Metallogr. Microstruct. Anal.

View full text Add to dashboard Cite

show abstract

“…In this study, the parameters in Eq. [3] were measured three to four times along various directions of the deformed samples; the mean values of the measured results were then used.…”

Section: Resultsmentioning

confidence: 99%

“…[1] [14] or [3] were obtained based upon an upper-bound theorem of rigid perfectly plastic materials. [14] The average friction coefficients at different temperatures were plotted in Figure 7 as a function of true strain.…”

Section: Resultsmentioning

confidence: 99%

“…A fundamental method in investigating the working behavior of materials is analyzing the true stress-true strain curves combined with the microstructure observation, which reflects their intrinsic mechanical properties of materials. However, friction between the material and the tools during the working process have to be considered before further investigation, [1][2][3][4][5] because practical measurements of the deformation curve depart from the real mechanical response of the materials to a certain degree. In practice, for many metalworking processes friction is the predominant factor.…”

Section: Introductionmentioning

confidence: 99%

“…The friction between a working piece and the jig can lead to heat generation, wear, pickup and galling of the tool surface, which contributes to the premature failure of the tools. [3][4][5] Friction increases nonhomogeneous deformation, leading to defects in the finished products. In addition, friction affects the evaluation of the deformation behavior of materials because the flow stress of the sample is strongly influenced by friction; this is especially true in hot compression processes, [6] where the friction is hard to eliminate completely even when the lubricant is added between the sample and anvil surfaces.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Correcting the Stress-Strain Curve in Hot Compression Process to High Strain Level

Onodera

Matsumoto

et al. 2009

Metall Mater Trans A

View full text Add to dashboard Cite

This article provides a model that regards the evolution behavior of the friction coefficient in the cylindrical compression test as a function of true strain on the basis of experimental results, allowing the effect of friction on the deformation curve at extremely high strain level to be evaluated and corrected for the first time. The compressive tests were carried out at a stroke rate of 1.2 mm/s on IHS38MSV hypoeutectoid steel with various lubricants at temperatures ranging from 800°C to 1200°C. The results showed that the friction coefficient for the compressive process was not constant and the variation could be approximated by an exponential equation along with the true strain. Microstructure observation showed that the stress increase in the later stages of process should be closely related to the large increase in the friction coefficient. The corrected curves were found to correlate well with the microstructure observation.

show abstract

Deformation Mechanisms and Microstructural Evolution of γ + γ′ Duplex Aggregates Generated During Thermomechanical Processing of Nickel‐Base Superalloys

et al. 2016

View full text Add to dashboard Cite

A mechanical interpretation of the activation energy of high temperature deformation in two phase materials

Cited by 123 publications

References 6 publications

Hot Forging of IN718 with Solution-Treated and Delta-Containing Initial Microstructures

Hot Forging of IN718 with Solution-Treated and Delta-Containing Initial Microstructures

Correcting the Stress-Strain Curve in Hot Compression Process to High Strain Level

Deformation Mechanisms and Microstructural Evolution of γ + γ′ Duplex Aggregates Generated During Thermomechanical Processing of Nickel‐Base Superalloys

Contact Info

Product

Resources

About