Elastic modulus and hardness of Ti alloy obtained by wire-feed electron-beam additive manufacturing

Introduction. The development and application of additive manufacturing depends on many factors, including the printing process performance and buy-to-fly ratio. Wire-feed electron-beam additive manufacturing (EBAM) is attracting more and more attention from research teams. Moreover, the use of electron beams is the most effective and competitive for additive manufacturing of parts from alloys possessing high oxidation characteristics, e.g., titanium, stainless steels, since selective laser melting occurs in vacuum. Welding titanium wire VT6sv is the most preferable choice due to its availability and a wide range of thickness. This alloy, however, has fewer alloying elements than VT6 (Ti–6Al–4V) alloys. The high performance of wire-feed 3D printing and the VT6sv alloy composition affect the structure, phase composition, and properties of the fabricated alloy. As is known, the elastic modulus and hardness of alloys are important parameters, which can be measured rapidly also using non-destructive testing. The purpose of this work is to study the application of different approaches to measuring the elastic modulus and hardness of products obtained by wire-feed EBAM using the equipment of the Institute of Strength Physics and Materials Science SB RAS. Research methods. The structure of VT6sv titanium alloys fabricated by 3D printing and VT1-0 (Grade 2), VT6 (Ti–6Al–4V) alloys, was investigated by different methods such as metallography, ultrasonic gauging, instrumented indentation technique, macro- and micro-indentation, indentation hardness testing. Results and Discussion. Titanium alloy fabricated from VT6sv titanium wire under different thermal conditions has a typical columnar structure throughout the forging height. The structure formation determines the elastic modulus and hardness at various points of the forging. It is found that the elastic modulus is higher than that of as-delivered Ti–6Al–4V alloys, while the hardness is lower. Micro-indentation shows lower values of the elastic modulus than macro-indentation, which approach to values obtained by ultrasonic gauging and in other works. Different values of the elastic modulus at different points of the 3D printed forging indicate its sensitivity to the structure and phase composition of the material and demonstrate capabilities of measuring techniques used in this work.