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Residual stresses in laser direct metal deposited Waspaloy

Moat, R. J. and Pinkerton, A. J. and Li, L. and Withers, P. J. and Preuss, M. (2011) Residual stresses in laser direct metal deposited Waspaloy. Materials Science and Engineering: A, 528 (6). pp. 2288-2298. ISSN 0921-5093

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Abstract

This paper reports a study into the effect of laser pulse length and duty cycle on the residual stress distributions in multi-track laser direct metal deposits of Waspaloy onto an Inconel 718 substrate. The residual stresses have been evaluated using neutron diffraction and the contour method, while electron microscopy and micro hardness indentation have been used to map the concomitant microstructural variation. In all cases, near the tops of the deposited walls, the longitudinal stresses are tensile towards the mid-length of the wall, while the stresses perpendicular to the substrate are negligible. By contrast near the base of the walls, the stresses along the direction of deposition are small, while the stresses perpendicular to the substrate are compressive at the centre and tensile towards the ends. Consistent with previous observations, the stresses parallel to free surfaces are tensile, balanced by compressive stresses in the interior (an inverse quench stress profile). These profiles have been found to be weakly dependent on the laser pulse parameters, most notably an increase in tensile stress gradient with increasing duty cycle, but the maximum residual stresses are largely unaffected. Furthermore, microstructural analysis has shown that the effect of laser pulse parameters on grain morphology in multi-track thick walls is less marked than previously reported for single-track wall structures.

Item Type: Article
Journal or Publication Title: Materials Science and Engineering: A
Uncontrolled Keywords: Residual stress ; Nickel-base superalloy ; Rapid manufacture ; Laser deposition ; Neutron diffraction ; Laser engineering net shaping (LENS)
Subjects: T Technology > TA Engineering (General). Civil engineering (General)
Departments: Faculty of Science and Technology > Engineering
ID Code: 59506
Deposited By: ep_importer_pure
Deposited On: 26 Oct 2012 14:41
Refereed?: Yes
Published?: Published
Last Modified: 24 Jan 2014 05:34
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/59506

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