scholarly journals Amplitude Dependent Internal Friction in Strained Magnesium Alloys of AZ Series

Crystals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 608
Author(s):  
Milan Uhríčik ◽  
Zuzana Dresslerová ◽  
Peter Palček ◽  
Mária Chalupová ◽  
Zuzanka Trojanová ◽  
...  
Keyword(s):  
Internal Friction ◽  
Quality Factor ◽  
Magnesium Alloys ◽  
Strain Amplitude ◽  
Room Temperature ◽  
Dislocation Line ◽  
Maximum Strain ◽  
Critical Amplitude ◽  
Solute Atoms

Amplitude dependent internal friction (ADIF) was measured in three AZ magnesium alloys. Two types of experiments were performed: ADIF was measured step by step with the increasing strain amplitude and ADIF was measured after predeformation of samples in torsion. All experiments were done at room temperature. The quality factor was used as a measure of internal friction (IF). The quality factor decreased in the region of smaller amplitudes, and approaching some critical amplitude, εcr, rapidly increased. This critical amplitude increased with increasing maximum strain amplitude and predeformation of samples up to ~6%. Such behavior can be explained by considering mobile solute atoms, which may migrate along the dislocation line in the region of smaller amplitudes and perpendicular to the dislocation line in the region of higher amplitudes. A competition between dragging and depinning of solute atoms with dislocation lines may very well explain the measured dependencies.

INTERNAL FRICTION STUDY OF ALUMINIUM ALLOY CONTAINING 7.5 WEIGHT PERCENT MAGNESIUM

1965 ◽  
Vol 43 (7) ◽  
pp. 1347-1357 ◽  
Author(s):  
B. N. Dey ◽  
M. A. Quader
Keyword(s):  
Internal Friction ◽  
Room Temperature ◽  
Low Frequency ◽  
Weight Percent ◽  
Peak Shift ◽  
Kcal Mole ◽  
Solute Atoms ◽  
Damping Peak ◽  
Weak Damping ◽  
Friction Study

Low-frequency internal-friction data were obtained using the torsion pendulum for the aluminium −7.5 wt% magnesium alloy in order to study the effects of quenching and aging on solute atom movements. A damping peak near 120 °C, attributed to the stress-induced reorientation of solute atoms (Zener relaxation), was found to shift to 80 °C on quenching. The activation energy for the peak at 80 °C was found to be 22.3 ± 1.5 kcal/mole, about 3 kcal/mole less than that for the Zener peak. The peak shift was found to be due to movement of solute atoms involving divacancies with reduced relaxation time. Aging of the quenched alloy at room temperature for one day was found sufficient to eliminate the effect of quenching in reducing relaxation time.Another weak damping peak near 40 °C in the as-quenched alloy specimen, attributed to the relaxation involving solute clusters, was found to be more pronounced on aging at room temperature for 24 hours, thereby indicating formation of zones in the quenched alloy during aging at room temperature. It was inferred from the results that about 100 atomic jumps were required to complete the relaxation responsible for this peak.Grain-boundary peaks were also observed in the furnace-cooled and the water-quenched specimens.

Newly Developed Heat Resistant Magnesium Alloy by Thixomolding®

2005 ◽  
Vol 488-489 ◽  
pp. 287-290 ◽  
Author(s):  
Tadayoshi Tsukeda ◽  
Ken Saito ◽  
Mayumi Suzuki ◽  
Junichi Koike ◽  
Kouichi Maruyama
Keyword(s):  
Aluminum Alloy ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Die Casting ◽  
The Other ◽  
Heat Resistant ◽  
Higher Temperature ◽  
Better Than

We compared the newly developed heat resistant magnesium alloy with conventional ones by Thixomolding® and aluminum alloy by die casting. Tensile properties at elevated temperatures of AXEJ6310 were equal to those of ADC12. In particular, elongation tendency of AXEJ6310 at higher temperature was better than those of the other alloys. Creep resistance of AXEJ6310 was larger than that of AE42 by almost 3 orders and smaller than that of ADC12 by almost 2 orders of magnitude. Fatigue limits at room temperature and 423K of AXEJ6310 was superior among conventional magnesium alloys.

Search for High Damping Metallic Glasses

2006 ◽  
Vol 319 ◽  
pp. 151-156 ◽  
Author(s):  
Y. Hiki ◽  
M. Tanahashi ◽  
Shin Takeuchi
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Internal Friction ◽  
Metallic Glass ◽  
Room Temperature ◽  
Temperature Stability ◽  
Temperature Peak ◽  
High Temperature Side ◽  
Side Slope ◽  
Temperature Side

In a hydrogen-doped metallic glass, there appear low-temperature and high-temperature internal friction peaks respectively associated with a point-defect relaxation and the crystallization. The high-temperature-side slope of low-temperature peak and also the low-temperature-side slope of high-temperature peak enhance the background internal friction near the room temperature. A hydrogen-doped Mg-base metallic glass was proposed as a high-damping material to be used near and somewhat above the room temperature. Stability of the high damping was also checked.

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