Temperature and dwell time effect on hardness of Al-base alloys

El‐Salam, F. Abd; Wahab, L.A.; Nada, R.H.; Zahran, H.Y.

doi:10.1007/s10853-006-1343-6

Cited by 8 publications

(5 citation statements)

References 22 publications

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“…With the increase of sliding velocity, the temperature of the frictional surface rises. The hardness of metal material usually decreases with the increase of temperature [34]. The wear rate of the samples under different normal loads at the sliding velocity 0.19 m/s is shown in Figure 7a.…”

Section: Wear Ratementioning

confidence: 99%

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Effect of the Addition of Rare Earth Element La on the Tribological Behaviour of AlSi5Cu1Mg Alloy

2018

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Abstract:The effects of 0, 0.3, 0.6 and 0.9 wt % modifier La on the dry sliding wear behaviours of AlSi5Cu1Mg alloy were investigated under different friction conditions (normal loads, sliding velocities) by using pin-on-disc configuration. The microhardness of the alloys was tested, and it was found that the microhardness of the alloys was improved by the La addition. The AlSi5Cu1Mg + 0.6 wt % La alloy exhibited the smallest grain size and maximum microhardness. The wear mechanism analysis of the worn surface was done, which drew support from a scanning electron microscope (SEM) that was equipped with an energy dispersive spectrometer. The results showed that AlSi5Cu1Mg + 0.6 wt % La alloy exhibited the best wear resistance, which was mainly due to the modified grain and microhardness. At the sliding velocity of 0.19 m/s, the adhesive wear became the main wear mechanism with the increase of the load because of the rupture of the oxide layer on the friction surface. Under the load of 3.8 MPa, the abrasive wear became slight as the sliding velocity increasing, due to the recrystallization phenomenon that happened in the frictional surface.

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Section: Wear Ratementioning

confidence: 99%

“…With the increase of sliding velocity, the temperature of the frictional surface rises. The hardness of metal material usually decreases with the increase of temperature [34]. …”

Section: Wear Ratementioning

confidence: 99%

Effect of the Addition of Rare Earth Element La on the Tribological Behaviour of AlSi5Cu1Mg Alloy

2018

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“…From Table 3, it is obvious that the dislocation creep is the dominant process taking place in the samples where 3.65 ≤ η ≤ 14.6. Furthermore, large values observed in Sm substituted samples were thought to be in the power law breakdown zone [66].…”

Section: Indentation Creepmentioning

confidence: 99%

Superconducting and Mechanical Properties of the Tl0.8Hg0.2Ba2Ca2Cu3O9−δ Superconductor Phase Substituted by Lanthanum and Samarium Fluorides

Khattar,

Anas,

Awad

et al. 2023

Condensed Matter

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This study investigated the impact of samarium and lanthanum fluorides (SmF3 and LaF3) on the physical and mechanical properties of Tl0.8Hg0.2Ba2Ca2−xRxCu3O9−δ−yFy superconducting phases (specifically the (Tl, Hg)-1223 phase), where R = Sm and La, with 0.00 ≤ x ≤ 0.10. The superconducting samples were synthesized using the solid-state reaction method. X-ray diffraction (XRD) verified the formation of the (Tl, Hg)-1223 phase without altering its tetragonal structure. Scanning electron micrographs (SEM) reveal the improvement of the grain size and inter-grain connectivity as Sm and La contents increased up to x=0.025. The electrical properties of (Tl, Hg)-1223 were studied using I-V and electrical resistivity measurements. Improved superconducting transition temperature (Tc) and transport critical current density (Jc) were observed up to x=0.025, beyond which they decreased substantially. Vickers microhardness (Hv) measurements were performed at room temperature to investigate their mechanical performance with various applied loads (0.49–9.80 N) and times (10–90 s). For both substitutions, the mechanical properties were enhanced up to an optimal value at x=0.025. All samples exhibited normal indentation size effect (ISE) behavior. The proportional sample resistance (PSR) model best explained Hv values among five theoretical models. Dislocation creep was the primary creep mechanism in the samples, according to indentation creep studies.

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“…Microhardness testing can be the easiest way to determine the mechanical properties of the different phases of the structure and follow aging behaviour during phase decomposition sequence [6] even at high temperature [7]. Hardness measurement can be related to mechanical properties such as yield stress σy, where in bulk materials [8]: H=3σy …………………………..……..……… 1A functional relationship between hardness H and temperature (T) has been reported as [9], H= HO exp (-α T) ……………………………………. (2) where HO is the hardness at zero K, or the intrinsic hardness, and α is the softening coefficient [7] or the coefficient of thermal expansion [10].…”

Section: Introductionmentioning

confidence: 99%

Anomalous Behaviour for Microhardness of Al-3wt.% Mg alloy

2010

Egyptian Journal of Solids

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Microhardness measurements, H, were obtained for sheets of Al-3wt.% Mg alloy in the temperature range 443-503 K, applied loads 10-300 gm and dwell times 10-40 sec. The age-hardening curves showed off leveling and pronounced oscillations indicating instability reflecting a competition between the effect of dynamic recovery or sub-structures coarsening and the effect of solute drag and precipitation hardening. The indentation size effect index (ISE), m, was calculated as 2 for the binary alloy indicating that, H, is independent on indentation size. Increasing temperature, T, load, L, and dwell time, t, caused a decrease in, H, due to the decrease of the amount of free Mg available for further precipitation hardening during the aging process. In general, increasing temperature, dwell time, applied load caused a decrease in hardness.

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Temperature and dwell time effect on hardness of Al-base alloys

Cited by 8 publications

References 22 publications

Effect of the Addition of Rare Earth Element La on the Tribological Behaviour of AlSi5Cu1Mg Alloy

Effect of the Addition of Rare Earth Element La on the Tribological Behaviour of AlSi5Cu1Mg Alloy

Superconducting and Mechanical Properties of the Tl0.8Hg0.2Ba2Ca2Cu3O9−δ Superconductor Phase Substituted by Lanthanum and Samarium Fluorides

Anomalous Behaviour for Microhardness of Al-3wt.% Mg alloy

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