EFFECT OF FILM PLASTICIZING UNDER MULTISTAGE ULTIMATE STRAIN

The results refer to changes of mechanical properties of thin-walled nickel-chromium alloy tube specimens after multistage cold drawing. The goal was to analyze the possibilities of changing the kinetics of hardening and destruction under influence of deposited metal oxide films. It has been noticed that under ultimate strain by drawing strength of coated tube specimens is much more than that of specimens without films. Specifically, the ultimate value of strain for coated tube specimens increases. At the same time the coated specimens have relatively high plasticity. The strength of coated specimens after ultimate strain is 14 – 23 % higher and plasticity is 4 times more. Specifically, that the ability of alloy to stand multistage ultimate strain can be increased more. It can be done by overlaying the film each time the specimen is drawn. In addition, there are the technological advantages of using the films under drawing. These advantages are the better quality of surface and decrease of drawing force. The possibility of effective application of plasticizing films to machining tools has been noted. The plasticity effect in this case is 50 – 70 % of that when films are deposited on material. Besides, they work as solid lubricants, decreasing power consumption for working and wear of tool. In explosive stamping tests of titanium-base alloy coating with oxide films resulted in double increase of plasticity