Structure formation of titanium alloys during vacuum-arc surfacing

Abstract

The work is based on wire vacuum-arc surfacing as one of the technologies for additive manufacturing. The results of the formation of structure and properties of a high-temperature titanium alloy of the Ti-Al-V-Mo-Zr system during vacuum-arc surfacing are presented. The structure of the surfaced materials consists of dendritic grains that are oriented in the direction opposite to heat removal. Some banding of the structure is observed. There is no porosity in the deposited layers for all surfacing modes. It was determined that a decrease in the surfacing current promotes an increase in the dispersion of the a-phase plates, which is accompanied by an increase in microhardness. With such a thermal cycle of surfacing, conditions are created for the formation of a favorable fine-dispersed martensitic structure with narrow a-colonies of small needles of the a-phase, providing a high microhardness at the level of 400HV.