JFET_V4_N2_RP5 M. Sivapragash P.R. Lakshminarayanan K. Raghukandan R. Karthikeyan M. Hanumantha Journal on Future Engineering and Technology 2230 – 7184 4 2 58 63 Magnesium alloy, Gas tungsten arc welding, Fatigue crack growth In this research work, Fatigue Crack Growth (FCG) characteristics are studied using axial fatigue test on Compact Tension (CT) specimen for as cast, heat treated and welded material. The relation ship between fatigue crack growth rate and stress intensity factor range for crack growth are analyzed. How ever, the results of da/dN-?K curves for CT specimens and Paris constants are determined. The heat treated specimen shows lower growth rate compared to as cast and welded materials. The fracture surfaces of the tested specimen are observed under a scanning electron microscope to understand the type of fracture. The fracture mode is observed as quasi cleavage. November 2008 - January 2009 Copyright © 2009 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=524