STRUCTURES AND DISTRIBUTION OF CHEMICAL ELEMENTS IN THE TRANSITION ZONE IN DEPOSITED VT20 AND VT1-0 ALLOY SAMPLES 

Abstract

Buildup (or additive manufacturing) processes enable the production of items with a differentiated chemical composition tailored to the purposes of their particular parts. However, the distribution of elements in the fusion zone and its sizes remain insufficiently understood. Samples of VT1-0 and VT20 titanium alloys were fused so that the VT1-0 alloy powder was deposited onto the VT20 cast alloy in one case and the VT20 titanium alloy powder was deposited onto the VT1-0 cast alloy in the other. Regardless of the grain-size and chemical composition of the powders, the chemical composition of the samples met the relevant standards for the alloys. The macrostructures were studied using a Neophot 32 optical microscope. Minimal porosity was revealed in the samples across all deposition options. The microstructural analysis also showed that the deposited material formed a uniform structure both longitudinally and transversely. The microstructure of the samples in the zones with specific chemical compositions resembled that of as-cast alloys. Variations in the sizes and shapes of structural components were observed near the powder/cast metal fusion line. A distinct transition zone was found in the fusion of titanium alloys with different chemical compositions. The chemical composition in the longitudinal and transverse sections of the sample in the powder/cast metal fusion zone was examined with a scanning electron microscope. The chemical composition was established at different distances from the fusion line. The data obtained showed that the chemical elements redistributed and their contents changed. The presence of zones with a changed chemical composition was ascertained by microstructural studies. The distribution of chemical elements was qualitatively assessed and showed that it was uniform.