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18

ANALYSIS, TESTING

JPRS-UMS-92-003 16 March 1992

composites tested herein. Specifically, thermomcchan-ical actions result in deformations, stratification, and cracking of the surface layers of composites. The fusion of glass fiber occurring at an emissive power of about 400 W/cm² or morę causes the fiber to break and thus diminishes the strength of the composite overall. The studies reported here demonstrated that the rates of graphite sublimation and glass vaporizaiton are Iow at temperatures less than or about 1,500 K and at pressures of 1.3 x 10² Pa or above. The studies further show that neither graphite sublimation nor glass vaporization make any significant contribution to the ratę of mass entrainment. The effect of the heat of the exothermal reactions of the decomposition products with oxygen were also found to be insignificant. Figures 5; references

10    (Russian).

A Study of the Microstructure and Mechanical Characteristics of 40Crl0C2Mo Steel After Laser Treatment

927D0049I Moscow FIZIKA IKHIMIYA OBRABOTKI MATERIALOY in Russian No 3, May-Jun 91 (manuscript received 14 May 90) pp 102-107

[Article by A.G. Grigoryants, S.I. Aleksenko, and A.N. Safonoy, Moscow]

UDC 621.785.54:669.14.018

[Abstract] The authors of the study examined the microstructure and mechanical characteristics of 40Crl0Si2Mo Steel after laser treatment by a continu-ous-wave C0₂ laser in the radiating power interval from 0.5 to 2.1 kW. The test specimens were first hardened in

011    at a temperaturę between 1,010 and 1,030°C and then tempered at a temperaturę between 760 and 780° to obtain a hardness (HRC) between 28 and 33. A Neophot-21 microscope was used for the metallographic analysis, a PMT-3 was used to measure microhardness under a load of 1 N, a DRON-3M diffractometer was used to determine the amount of residual austenite, and an SMTs-2 friction-testing machinę was used to test dura-bility. The experiments performed established that when 40Crl0C2Mo Steel is subjected to laser treatment in modes involving fusion of the surface due to concen-trated inhomogeneity, the fusion zonę is madę up of extrahard martensite cells surrounded by a thin grid of residual austenite. This structural pattem results in a significant improvement in the steefs mechanical characteristics. Laser treatment of 40Crl0C2Mo Steel in a modę inducing surface fusion was also found to result in a jumplike increase in the durability of the laser paths analogous to the change in microstructure and hardness. The durability resulting from laser treatment involving surface fusion proved to be greater than the durability induced in Steel by chromizing and laser surfacing with PG-SR3 powder but somewhat less than the durability resulting from ion nitriding. The best results were obtained by applying single paths at a 45° angle to the cylinder axis. The endurance limit of 40Crl0C2Mo subjected to laser treatment until surface fusion occurred and then subjected to pure bending coupled with rota-tion was found to be 4 to 6% higher than before bending and 25 to 27% greater than the endurance of specimens subjected to galvanic chromizing. Figures 4, tables 3; reference 1 (Russian).

The Interaction of Radiation Defects With Lithium Impurity Atoms in Aluminum

927D0049C Moscow FIZIKA I KHIMIYA OBRABOTKI MATERIALOY in Russian No 3,

May-Jun 91 (manuscript received 11 Mar 90) pp 30-32

[Article by V.L. Arbuzov, A.E. Davletshin, I.Ye. Podchi-nenov, and S.M. Klotsman, Sverdlovsk]

UDC 539.1.043:069.71

[Abstract] The authors of the study examined the interaction occurring between radiation defects and lithium impurity atoms in aluminum. Diluted alloys of Al + 15 ppm Li and Al + 64 ppm Li based on type A999 aluminum were used for the studies. The alloys were prepared by remelting the Al-Li foundry alloy with pure Al in a graphite crucible in an atmosphere of pure helium. The specimens were irradiated in a continuous-type helium cryostat on a linear electron accelerator with an energy of 5.5 MeV at a temperaturę of 54 K. The studies performed indicated that lithium atoms in aluminum function as traps for interstitial atoms. The relative radius of the capture of the interstitial atoms by lithium impurity atoms at 54 K was found to equal 0.22 +/- 0.03, whereas the radius of capture of interstitial atoms by complexcs consisting of an interstitial atom of the aluminum itself and a lithium atom equals 1.8 +/-0.2. The studies further revealed that the radii of the capture of interstitial atoms by impurity atoms can be correctly determined only at Iow irradiation doses (Ap < 0.2 to 0.4 nQ x cm depending on the impurity concen-tration [CJ and relative radius of the capture of the interstitial atoms of the metal itself by impurity atoms [R_t]). Figures 2; references 8: 4 Russian, 4 Western.

The Effect of a Metal’s Defect Structure on Interstitial łon Distribution Profile

927D0049B Moscow FIZIKA I KHIMIYA OBRABOTKI MATERIALOY in Russian No 3,

May-Jun 91 (manuscript received 24 May 90) pp 27-29

[Article by V.I. Boyko, B.Ye. Kadlbovich, and I.V. Shamanin, Tomsk]

UDC 539.124

[Abstract] The correctness of ignoring “three-dimensional” structural defects when conducting research involving the bombardment of metal targets with ion beams is controversial. In an effort to clarify this matter, the authors of the study used the method of Computer simulation to study the effect that the defect