INTERNAL FRICTION AND MODULUS MEASUREMENTS IN COLD-WORKED AND ELECTRON-IRRADIATED COPPER AT LOW FREQUENCIES

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INTERNAL FRICTION AND MODULUS MEASUREMENTS IN COLD-WORKED AND ELECTRON-IRRADIATED COPPER AT LOW

FREQUENCIES

H. Brumme, H. Ebener, G. Sokolowski

To cite this version:

H. Brumme, H. Ebener, G. Sokolowski. INTERNAL FRICTION AND MODULUS MEASURE- MENTS IN COLD-WORKED AND ELECTRON-IRRADIATED COPPER AT LOW FREQUEN- CIES. Journal de Physique Colloques, 1971, 32 (C2), pp.C2-147-C2-147. �10.1051/jphyscol:1971231�.

�jpa-00214557�

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JOURNAL DE PHYSIQUE Colloque C2, supplkment au no 7 , tome 32, Juillet 1971, page C2-147

INTERNAL FRICTION AND MODULUS IW3ASUREMENTS IN COLD-WORKED AND ELECTRON-IRRADIATED COPPER AT LOW FREQUENCIES

H. BRUMME, H. EBENER and G. SOKOLOWSKI Institut fiir Allgemeine Metallkunde und Metallphysik

der Technischen Hochschule Aachen The effect of cold-work and of 3 MeV electron

irradiation on the internal friction and the shear modulus of polycrystalline copper was measured at 1 Hz. The general features of the results will be briefly discussed.

Figure l a gives the decrement as a function of temperature for the undeformed sample, the sample after 7

%

cold-work at 78 OK, and the annealed sample. The main structure of the curve after deformation (filled circles) is the peak P, at about 160 OK.

The peak temperature is shifted to lower values by increasing plastic deformation and can be related to the dislocation density of the samples. For tempe- ratures above 200 OK there is no pronounced structure, several damping processes seem to increase the background without yielding well-defined peaks.

In particular, we cannot resolve that relaxation process, that was interpreted to be due to

the relaxation of the

<

100 >-split interstitial.

Figure l b gives the corresponding decrement curves for a sample irradiated with 3 MeV electrons at lOOOK up to a defect concentration of 3 X 10-7.

Between 120 OK and 330 OK the difference between the irradiated and the unirradiated sample gives a very broad peak. A 10 min. anneal at 360 OK reduces the radiation-induced increase of decrement comple- tely above 100 OK, and the curve of the unirradiated sample is reproduced. The fact that here the irradiation increases the internal friction does not fit the com- monly accepted views on dislocation damping. It must be assumed that the point defects themselves or in interaction with dislocations produce this very broad peak. This smeared-out increase of internal friction due to electron irradiation is very similar to that after cold-work, as can be seen by comparing the full-circle-curves in figure l a and l b .

( a ( b )

FIG. 1. -Decrement vs temperature.

a. - For 7 % cold-work at 78 OK. b.

-

For irradiation with 4 X 1 0 1 6 electrons/cmz at 100 OK.

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1971231