Crystallographic texture and microstructure of pulsed diode laser-deposited Waspaloy

The role of both laser Pulse length and duty cycle in controlling the grain size and crystallographic texture of diode laser-deposited Waspaloy powder is investigated. Thin-walled test structures of Waspaloy have been produced Using a range of pulse parameters and analyzed by means of scanning electron microscopy and electron backscatter diffraction. Results have been correlated with a simple analytical model of the effect of the laser pulse oil the substrate temperature and melt-pool geometry in order to help explain the trends observed. Findings show that Pulse parameters have a marked effect oil the resulting grain morphology and crystallographic orientation. Modelling has indicated that this arises because the microstructure Lire is highly dependent oil the melt-pool geometry, particularly the inclination angle of the melt-pool boundary. (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.