OBRABOTKA METALLOV

Abstract
The influence of non-vacuum electron beam treatment modes on the structure and properties of wear resistant TiB-TiC-Ti layers formed on the surface of VT1-0 titanium alloy is investigated. A mixture of titanium, boron carbide and flux powders is used as filler. The structure and phase composition of the layers are investigated by the means of optical microscopy and scanning electron microscopy, and X-ray diffractometry. The experiments resulted in the formation of layers with the thickness of 3.4 mm consisting of α (α´)-Ti, titanium carbide and titanium monoboride. Structural investigations revealed a high volume fraction of TiC and TiB reinforcing compounds contributed in the formation of cracks in the cladded layers. Variation of technological regimes of the electron beam treatment affected the hardness of cladded layers. Treatment of the sample containing 20 wt. % of boron carbide in a filler with a beam current of 22 µA led to the formation of the layer with hardness of 582 HV. This value was about 3.5-fold higher than titanium microhardness. Increase of a beam current by 1 µA resulted in decrease of the microhardness level to 543 HV. Treatment of the sample containing 12 wt. % of boron carbide in a filler led to the formation of the layer with hardness of 436 HV.

Wear resistance of fabricated materials is estimated in the conditions of friction by non-rigidly fixed abrasive particles. The best characteristics possessed the layers obtained by cladding of 20 wt. % boron carbide. Intensity of wear of the coated samples was 8-fold lower comparing to cp-titanium.

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