Microstructure and properties of LENS (laser engineered net shaping) manufactured Ni-Ti shape memory alloy

Successful attempt of laser deposition of a nitinol alloy is presented in this paper. The influence of the deposition velocity on the alloy microstructure and phase composition was investigated. Nine samples with different scanning velocities and layer thicknesses were manufactured using the LENS process. The effect of different laser parameters on the microstructure, secondary phase compositions and functional properties of the nitinol alloy was examined using optical microscopy, X-ray diffraction and DSC analyses. The microstructural characteristics, factors influencing the transformation temperatures and phase analyses are discussed to show the Ni-Ti alloy behaviour and great challenges in front of additive manufacturing applications for nitinol part manufacturing. (C) 2018 Elsevier B.V. All rights reserved.