High-temperature internal friction in a Fe–38at.% Al intermetallic

Simas, P.; Juan, J. San; Nó, M.L.

doi:10.1016/j.msea.2008.10.063

Cited by 7 publications

(5 citation statements)

References 13 publications

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“…This problem is usually solved by fitting the expression of the HTB and subtracting it from the IF spectra, to obtain the isolated relaxation peak. Nevertheless, although this method has been successfully applied to high-temperature intermetallics, [28][29][30] it cannot be applied in the present case because the HTB has been measured only in a narrow temperature range not wide enough to fit it properly. In fact, the sample must not be heated above 993 K for a long time, in order to avoid the precipitation processes during the thermal run along each measurement; consequently, we kept the temperature below 1010 K in all runs except for the last measurement at 3 Hz.…”

Section: A Analysis Of the Relaxation Peakmentioning

confidence: 99%

Atomic Species Associated with the Portevin–Le Chatelier Effect in Superalloy 718 Studied by Mechanical Spectroscopy

Max

Juan

Nó

et al. 2018

Metall Mater Trans A

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In many Ni-based superalloys, dynamic strain aging (DSA) generates an inhomogeneous plastic deformation resulting in jerky flow known as the Portevin-Le Chatelier (PLC) effect. This phenomenon has a deleterious effect on the mechanical properties and, at high temperature, is related to the diffusion of substitutional solute atoms toward the core of dislocations. However, the question about the nature of the atomic species responsible for the PLC effect at high temperature still remains open. The goal of the present work is to answer this important question; to this purpose, three different 718-type and a 625 superalloy were studied through a nonconventional approach by mechanical spectroscopy. The internal friction (IF) spectra of all the studied alloys show a relaxation peak P 718 (at 885 K for 0.1 Hz) in the same temperature range, 700 K to 950 K, as the observed PLC effect. The activation parameters of this relaxation peak have been measured, E a (P 718) = 2.68 ± 0.05 eV, s 0 = 2AE10 À15 ± 1 s as well as its broadening factor b = 1.1. Experiments on different alloys and the dependence of the relaxation strength on the amount of Mo attribute this relaxation to the stress-induced reorientation of Mo-Mo dipoles due to the short distance diffusion of one Mo atom by exchange with a vacancy. Then, it is concluded that Mo is the atomic species responsible for the high-temperature PLC effect in 718 superalloy.

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Section: A Analysis Of the Relaxation Peakmentioning

confidence: 99%

Atomic Species Associated with the Portevin–Le Chatelier Effect in Superalloy 718 Studied by Mechanical Spectroscopy

Max

Juan

Nó

et al. 2018

Metall Mater Trans A

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“…Anelastic temperature- and frequency-dependent effects in Fe–Al alloys were reviewed in [ 66 ] and several later publications [ 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 ]. Fe–Al alloys have good damping properties due to magneto-mechanical decay of mechanical vibrations in the Hz range of loading.…”

Section: Introductionmentioning

confidence: 99%

Anelastic Effects in Fe–Ga and Fe–Ga-Based Alloys: A Review

Golovin

2023

Materials

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Fe–Ga alloys (GalFeNOLs) are the focus of attention due to their enhanced magneto-elastic properties, namely, magnetostriction in low saturation magnetic fields. In the last several years, special attention has been paid to the anelastic properties of these alloys. In this review, we collected and analyzed the frequency-, amplitude-, and temperature-dependent anelasticity in Fe–Ga and Fe–Ga-based alloys in the Hertz range of forced and free-decay vibrations. Special attention is paid to anelasticity caused by phase transitions: for this purpose, in situ neutron diffraction tests with the same heating or cooling rates were carried out in parallel with temperature dependencies measurements to control ctructure and phase transitions. The main part of this review is devoted to anelastic effects in binary Fe–Ga alloys, but we also consider ternary alloys of the systems Fe–Ga–Al and Fe–Ga–RE (RE—Rare Earth elements) to discuss similarities and differences between anelastic properties in Fe–Ga and Fe–Al alloys and effect of RE elements. We report and discuss several thermally activated effects, including Zener- and Snoek-type relaxation, several transient anelastic phenomena caused by phase transitions (D03 ↔ A2, D03 → L12, L12 ↔ D019, D019 ↔ B2, Fe13Ga9 → L12+Fe6Ga5 phases), and their influence on the above-mentioned thermally activated effects. We also report amplitude-dependent damping caused by dislocations and magnetic domain walls and try to understand the paradox between the Smith–Birchak model predicting higher damping capacity for materials with higher saturation magnetostriction and existing experimental results. The main attention in this review is paid to alloys with 17–20 and 25–30%Ga as the alloys with the best functional (magnetostriction) properties. Nevertheless, we provide information on a broader range of alloys from 6 to 45%Ga. Due to the limited space, we do not discuss other mechanical and physical properties in depth but focus on anelasticity. A short introduction to the theory of anelasticity precedes the main part of this review of anelastic effects in Fe–Ga and related alloys and unsolved issues are collected in summary.

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“…In the last decade a new approach, by mechanical spectroscopy, is being used to study the mobility of defects at high temperature in structural intermetallics as FeAl [19e22] and TiAl [23e27]. A relationship between the internal friction high temperature background (HTB), measured by mechanical spectroscopy, and the high temperature creep behaviour in intermetallics has been proposed in several works [21,22,24,26] being still a matter of discussion.…”

Section: Introductionmentioning

confidence: 99%