Scientia Sinica

No. 1 KE, MA: INTERNAL FRICTION ASSOCIATED WITH TEMPERING OF MARTENSITE 31

high temperatures, that is, the 235°C peak (see Fig. 1) does not exist. If the 235°C peak is associated with a certain state of stress existing in the’ specimen"), then it is difficult to see why the existence of martensite in the specimen does not create a state of stress in the specimen.

Another internal friction peak having a peculiar shape as shown in Fig. 10 was observed with a specimen carburized at 910°C for one hour and

Temperature (°C) 200 180160140 120 100 80 60 ~- 40 20

0.010 0.008

0.006

0.004

Internal Friction (Q-!)

0.002

2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 1000/T —>

Fig. 10. Internal friction peak in a 0.72—1.0%'C specimen air-cooled

from 910°C and its disappearance with lowering temperature.

then air-cooled. This internal friction peak also does not rise again at higher temperatures. The carbon content of this specimen is estimated at 0.72-1.0% from the carburizing temperature and time.

REFERENCES

Kypztomos, I. B., mw JIpicax, JI., 1949. AAT®, 19,525.

Roberts, C. S., Averbach, B. L., and Cohen, M., 1953. Trans. ASM, 45, 576.

Jack, K. H.,-1951. J. Iron Steel Inst., 169, 26.

Worrell, F. T., in Zener, C., 1948. Elasticity and Anelasticity of Metals (University of Chicago Press), pp. 159—163.

Siefert, A. V., and Worrell, F. T., 1951. J. App. Phys. 22, 1257.

Ké, T. S., 1947. Phys. Rev., 71, 533.

Ké, T. S., Yung, P. T., and Wang, Y. N., 1955. Acta Physica Sinica, 11, 91; Scientia Sinica, 4, 263.

[7] Lement, B. S., Averbach, B. L., and Cohen, M., 1954. Trans. ASM, 46, 851.

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