A Novel Simplified Approach to Physically Simulate Wire-Arc Directed Energy Deposition Conditions

Scarcity of specialized titanium alloy wires impedes wire-arc directed energy deposition adoption in industry. Additionally, wire manufacturing on experimental level is elaborate. Here, a novel, physical simulation approach is presented, aimed to accelerate and economize titanium alloy development by generating wire-arc directed energy deposition conditions in the microstructure without using wire as pre-material. An adjustable plasma torch mounted on a KUKA robot (re-)melts the bar-shaped samples, mimicking the wire-arc directed energy deposition process first stages, creating a microstructure near identical to a wire-arc directed energy deposited one. Ti-6Al-4V sheet, as-built wire-arc directed energy deposited material, and both after plasma re-melting were characterized using various microscopy techniques, electron backscatter diffraction, microhardness tests, and four-point bending. Results demonstrate congruence between wire-arc directed energy deposited and plasma re-melted material, including process-specific phenomena like columnar grain growth and crystallographic texture, which results in orientation dependent elastic bending moduli. This method may offer a new tool for rapid alloy development for wire-arc directed energy deposition applications since the approach eliminates the need for costly wire production and permits the use of any small bar-shaped casting.