Title: Effect of processing parameters and microstructural defects on fatigue properties of direct metal laser sintered bronze–nickel parts

Authors: C.D. Naiju; M. Adithan; P. Radhakrishnan

Addresses: School of Mechanical and Building Sciences, VIT University, Vellore 632 014, Tamil Nadu, India ' Academic Staff College, VIT University, Vellore 632 014, Tamil Nadu, India ' Institute of Advanced Studies, PSG Tech, Coimbatore 641 004, Tamil Nadu, India

Abstract: Production of bronze–nickel parts was undertaken by solid freeform fabrication method involving direct metal laser sintering (DMLS). Sintering speed, scan spacing and hatch pattern were considered as effective process variables governing the quality of parts manufactured. Two values were chosen for each of these process variables and tests for studying their effect on fatigue cycles failure using Taguchi technique. To understand the, generally, observed scatter in mechanical properties of DMLS parts, specimens produced under different processing conditions were also subjected to microstructural examination by optical microscopy and scanning electron microscopy. Microstructural defects include regions containing micro- as well as macro-segregation of bronze which cause the observed scatter in mechanical properties of DMLS parts. The likely physical reasons for the occurrence of these microstructural defects have been explained. From the analysis of results of fatigue test, it has been concluded by contribution of different processing parameters.

Keywords: DMLS; direct metal laser sintering; microstructure; fatigue strength; bronze; nickel; solid freeform fabrication; SFF; sintering speed; scan spacing; hatch pattern; Taguchi methods.

DOI: 10.1504/IJRAPIDM.2011.043456

International Journal of Rapid Manufacturing, 2011 Vol.2 No.3, pp.150 - 161

Published online: 18 Feb 2015 *

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