Trend of Metal 3D Printing by WeldingJae-Gyu Byun* and Sang-Myung Cho** , † *Dept. of Materials System Engineering, Graduate School, Pukyong National University, Busan 48513, Korea **Dept. of Materials System Engineering, Pukyong National University, Busan 48513, Korea † Corresponding author : pnwcho@pknu.ac.kr (Received June 14, 2016 ; Revised July 13, 2016 ; Accepted July 29, 2016) AbstractMetal AM(Additive Manufacturing) has been steadily developed and that is classified into two method. PBF(Powder Bed Fusion) deposited in the bed by the laser or electron beam as a heat source of the powder material and DED(Directed Energy Deposition) deposited by varied heat source of powder and solid filler material. In the developed countries has been applying high productivity process of solid filler metal based DED method to the aerospace and defense sectors. The price of the powder material is quite expensive compared to the solid filler metal. A study on DED method that is based on a solid filler metal is increasing significantly although was low accuracy and degree of freedom.

RThe present work investigates the microstructure and mechanical properties of Ti-6Al-4V fabricated using directed energy deposition(DED) additive manufacturing process. Specially, the mechanical properties and microstructures of the Ti-6Al-4V plate with post-process heat treatment were studied. Rectangular parts were built in the Argon gas shielding box with condition laser power 280W, 310W, 340W. The as-built plates were heated to 954℃ below b-transus and then furnace cooled after holing for 2hours. The yield and ultimate tensile strength values for the building layer as-built plate in laser power 280W of 1,105±21 and 1,224 ± 10MPa respectively are different from values obtained from the building layer with post-process heat treatment of 789 ± 5 and 886 ± 9 MPa. There is also a significant difference in the elongation between as-built plate and postprocess heat treatment plate with an engineering strain to failure of 3.5± 0.7% and 12.1± 1.1% in the plate. The microstructure in post-process heat treatment plate consists mostly of widmanstätten structure, whereas the as-built plate consists of martensitic structure in the columnar prior-β grain.