Internal Friction of Cast Graphite-Magnesium Composites

1988 ◽  
Vol 120 ◽  
Author(s):  
J. H. Armstrong ◽  
S. P. Rawal ◽  
M. S. Misra
Keyword(s):  
Internal Friction ◽  
Strain Amplitude ◽  
Friction Model ◽  
Piezoelectric Composite ◽  
Amplitude Dependence ◽  
Friction Behavior ◽  
Dislocation Densities ◽  
The Matrix ◽  
Composite Strain ◽  
Zr Alloy

AbstractInternal friction behavior in cast 8-ply [0°1 P55Gr/Mg-0.6%Zr alloy and P55Gr/Mg-1%Mn composites as a function of vibratory strain amplitude was measured at 80 kHz using a Marxtype piezoelectric composite oscillator. Both the matrix and composite exhibited strain amplitude independent internal friction below ε ≈ 10−6, while significant strain amplitude dependence was noted at higher strain levels. A maxima in damping was observed for most of the specimens tested. Heat treatment to enlarge grain size was found to increase both the strain amplitude independent and dependent internal friction of the composite. Strain amplitude dependence of the internal friction, including the existence of the maxima, was explained by the Granato-Lucke (G-L) dislocation internal friction model. Dislocation densities obtained from various TEM images from the fiber-matrix interface were compared to values predicted by G-L theory.

Internal Friction during Reverse Martensitic Transformation in Mn-Cu Alloy with 45 % Mn

2013 ◽  
Vol 738-739 ◽  
pp. 183-186 ◽  
Author(s):  
Galina Viktorovna Markova ◽  
Ekaterina Sergeevna Klyueva
Keyword(s):  
Heat Treatment ◽  
Martensitic Transformation ◽  
Low Temperature ◽  
Internal Friction ◽  
Temperature Dependence ◽  
Strain Amplitude ◽  
Physical Mechanism ◽  
Amplitude Dependence ◽  
Internal Friction Peak ◽  
Cu Alloy

The temperature and amplitude dependence of internal friction fcc Mn45Cu55 alloy aged at 400 °C were studied. Two low-temperature internal friction peak observed in the quenched state. Physical mechanism of the peaks was determined by the effect of frequency and strain amplitude on the temperature dependence of internal friction. The influence of the heat treatment to the internal friction of the investigated alloy was shown.

Temperature and strain amplitude dependence of internal friction measured with an automatic pendulum

1984 ◽  
Vol 17 (2) ◽  
pp. 121-123 ◽  
Author(s):  
F Povolo ◽  
B J Molinas ◽  
A F Armas
Keyword(s):  
Internal Friction ◽  
Strain Amplitude ◽  
Amplitude Dependence

Stress Relaxation Behavior of Cu-Ni-P Alloys Evaluated from Amplitude-Dependent Internal Friction

2012 ◽  
Vol 184 ◽  
pp. 245-250
Author(s):  
Yasuhiro Aruga ◽  
Yoshiki Morikawa ◽  
Satoshi Tamaoka ◽  
Yoichi Nishino
Keyword(s):  
Stress Relaxation ◽  
Plastic Strain ◽  
Internal Friction ◽  
Strain Amplitude ◽  
Annealing Time ◽  
Three Dimensional ◽  
Atom Probe ◽  
Dislocation Motion ◽  
Amplitude Dependence ◽  
Stress Relaxation Behavior

The strain-amplitude dependence of internal friction in Cu-0.41Ni-0.11P (mass%) alloys has been evaluated to reveal the relation between the amplitude-dependent internal friction and the stress relaxation performance. Annealing at 250°C after cold rolling causes a suppression of the strain-amplitude dependence with increasing annealing time in the range between 10 s and 104 s. Analysis of the amplitude-dependent internal friction reveals the plastic strain of the order of 10-9 as a function of effective stress on dislocation motion. It is found that the microflow stress at a constant level of plastic strain increases with increasing annealing time. This result is in line with the improvement in the stress relaxation performance but disagrees with a decrease in the tensile strength and yield stress after annealing. We believe that the increase in the microflow stress after annealing is caused by inhibition of dislocation motion due to Ni-P clusters, which were revealed by three-dimensional atom probe (3DAP) experiments.

ENHANCED STRAIN AMPLITUDE DEPENDENCE OF INTERNAL FRICTION IN THE MIXED STATE OF NIOBIUM

1968 ◽  
Vol 13 (10) ◽  
pp. 362-364
Author(s):  
Edward J. Kramer ◽  
Charles L. Bauer
Keyword(s):  
Internal Friction ◽  
Strain Amplitude ◽  
Mixed State ◽  
Amplitude Dependence ◽  
Enhanced Strain

Mechanical Damping and Dynamic Modulus Measurements in Continuous Fiber-Reinforced Composite Materials: Al/Al2O3 and Al/W

1989 ◽  
Vol 153 ◽  
Author(s):  
Alan Wolfenden ◽  
Jeffrey M. Wolla
Keyword(s):  
Strain Amplitude ◽  
Aluminum Matrix ◽  
Amplitude Dependence ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Continuous Fiber ◽  
Damping Behavior ◽  
Dislocation Densities ◽  
Mechanical Damping ◽  
Increasing Temperature

AbstractMeasurements of mechanical damping, or internal friction (Q−1), and dynamic Young's modulus (E) have been made near 80 kHz and at strain amplitudes (ε) in the range of 10−8 to 10−4 on small specimens of the following two continuous fiber-reinforced metal matrix composites (MMCs): 6061 aluminum reinforced with alumina (Al/A12O3) and 6061 aluminum reinforced with tungsten (AI/W). Baseline experiments were also performed on 99.999% aluminum (pure Al) for comparison puposes. The temperature (T) dependence of modulus up to 475°C was determined for AI/A12O3 and pure Al. The rate of modulus decrease with increasing temperature for AI/A12O3 and Al was the same, that is, dE/dT was essentially the same for both materials. Thus, the reduction in modulus observed for the Al/Al2O3 was attributed to the reduction in modulus of the Al matrix and not that of the Al2O3 fibers. The strain amplitude dependence of damping was examined for all three materials. The pure Al exhibited classical dislocation damping behavior with strain amplitude dependent damping starting at a strain of 2 × 10−5. The Al/Al2O3 specimens showed only mild dependence of damping on strain amplitude starting at strains near 10−5. The AI/W exhibited significant amplitude dependence of damping starting at strains of 2 × 10−6 with the fiber diameter being a major factor in determining the damping behavior. The Q−1 versus ε data for Al/Al2O3, when analyzed in terms of the Granato-Lücke (GL) theory for dislocation damping, yielded minor pinning lengths of dislocations near 10−8 m and mobile dislocation densities near 1011 m−2. The same analysis for the Al/W data gave values near 10−8 m for the minor pinning lengths and 1012 M−2 for the dislocation density. Relative to the results for pure Al, the minor pinning lengths for Al/Al2O3 and AL/W are comparable (10−8 m for pure Al), but the dislocation densities are much higher (109 m−2 found in the pure Al). The relatively high dislocation densities calculated for these aluminum matrix MMCs agree with previous findings of other researchers and may be associated with the fiber/matrix interface.

Strain amplitude dependence of internal friction and strength of submicrometre-grained copper

1993 ◽  
Vol 171 (1-2) ◽  
pp. 143-149 ◽  
Author(s):  
R.R. Mulyukov ◽  
N.A. Akhmadeev ◽  
R.Z. Valiev ◽  
S.B. Mikhailov
Keyword(s):  
Internal Friction ◽  
Strain Amplitude ◽  
Amplitude Dependence

Effects of Pinning and Atomic Ordering on Damping Properties and Martensitic Transformation of Copper-Based Shape Memory Alloys

2012 ◽  
Vol 184 ◽  
pp. 366-371 ◽  
Author(s):  
S. Kustov ◽  
E. Cesari ◽  
Jan Van Humbeeck
Keyword(s):  
Martensitic Transformation ◽  
Internal Friction ◽  
Shape Memory ◽  
Long Range ◽  
Strain Amplitude ◽  
High Amplitude ◽  
Amplitude Dependence ◽  
Atomic Order ◽  
Damping Properties ◽  
Range Atomic Order

The effects of long-range atomic order and pinning of interfaces on anelastic properties of Cu-based martensite have been distinguished by means of studying strain amplitude dependences of internal friction and Young’s modulus defect, assuming that low-and high-amplitude stages of the strain amplitude dependence correspond to the oscillations within and beyond pinning atmospheres.

Sign in / Sign up

Export Citation Format

Share Document