Ahsan, M. Naveed and Pinkerton, Andrew J. and Ali, Laiq (2012) A comparison of laser additive manufacturing using gas and plasma-atomized Ti-6A1-4V powders. In: Innovative Developments in Virtual and Physical Prototyping :. CRC PRESS-TAYLOR & FRANCIS GROUP, Leiria, pp. 625-633. ISBN 978-0-415-68418-7
Full text not available from this repository.Abstract
This research presents a comparative study of the characteristics of laser additive manufacturing (LAM) using two types of Ti-6A1-4V powder. Ti-6A1-4V powders prepared using the gas-atomization (GA) and the plasma rotating electrode (PREP) processes were first analyzed using laser diffraction, scanning electron microscopy and microcomputed tomography. A 1.5 kW diode laser with a coaxial deposition head was then used to deposit a number of thin-wall structures at a range of processing parameters from each of the powders. The deposited structures were characterized using optical microscopy, scanning electron microscopy, x-ray diffraction and microcomputed tomography (MicroCT). In both cases, deposits of Ti-6A1-4V exhibit a unique epitaxial prior beta grains microstructure that transforms to alpha lathes and retained beta during cooling. X-ray diffraction results show that the overall microstructure is alpha + beta. The lamellar alpha + beta phase spacing (S alpha+beta) increases with laser power but seems unaffected by variation in the powder mass flow rate. Micro hardness of the laser deposited Ti-6A1-4V is dependent on the lamellar a 0 phase spacing (S alpha+beta). The results show some potential benefits of using PREP powder in laser additive manufacturing. PREP powder has a higher deposition rate and deposits show lower intralayer porosity and lower surface roughness. However, PREP powder deposits show lower micro hardness than GA powder deposits.