MICROSTRUCTURE AND MECHANICAL PROPERTIES OF TI-6AL-4V ALLOY FABRICATED BY WIRE ARC ADDITIVE MANUFACTURING

Abstract

The paper presents a systematized analytical synthesis of the current body of experimental data regarding the arc additive manufacturing of Ti-6Al-4V titanium alloy, focusing on Wire Arc (WAAM) and Gas Tungsten Arc (GTAW-AM) technologies. WAAM is an arc-based additive manufacturing technology derived from conventional welding processes. The synthesis focuses on quantitative relationships between deposition parameters, thermal cycling effects, microstructural evolution, and anisotropy of mechanical properties. It is demonstrated that heat input control, interpass temperature, and deposition path strategy govern prior-β grain growth and α-phase morphology. Repeated thermal exposure inherent to layer-by-layer deposition promotes the formation of columnar prior-β grains aligned with the build direction and height-dependent α-lath coarsening, resulting in hardness gradients and anisotropy of tensile strength. Optimized GTAW-AM parameters ensure geometric stability of deposited beads and tensile strength exceeding 900 MPa. For the WAAM process under controlled interpass temperature conditions, the formation of refined Widmanstätten-type lamellar structures is characteristic, contributing to improved strength. In addition, comparative analysis of mechanical properties reveals pronounced anisotropy in ultimate tensile strength, yield strength, and elongation depending on specimen orientation relative to the build direction. Typical technological defects inherent to arc-based additive manufacturing, including porosity, residual stresses, and microstructural heterogeneity, are associated with heat input and cooling conditions. The findings define a consistent process–structure–property relationship for arc-based additive manufacturing of Ti-6Al-4V and provide a scientifically grounded basis for optimization of arc-based AM technologies for critical structural components.