Additive manufacturing of Ti-6Al-4V components by shaped metal deposition: Microstructure and mechanical properties

Shaped metal deposition (SMD) is a relatively new technology of additive manufacturing, which creates near-net shaped components by additive manufacture utilizing tungsten inert gas welding. Especially for Ti alloys, which are difficult to shape by traditional methods and for which the loss of material during machining is also very costly, SMD has great advantages. In the case of Ti-6Al-4V the dense SMD components exhibit large, columnar prior beta grains, with a Widmanstatten alpha/beta microstructure. These prior beta grains are slightly tilted in a direction following the temperature field resulting from the moving welding torch. The ultimate tensile strength is between 929 and 1014 MPa, depending on orientation and location of the tensile specimens. Tensile testing vertically to the deposition layers exhibits a strain at failure of 16 +/- 3%, while testing parallel to the layers gives a lower value of about 9%. (C) 2009 Elsevier Ltd. All rights reserved.