Bending Fatigue Resistance of Duplex Shot Peened Austempered Ductile Iron

Author:  W. Abela1, G. Cassar1, A. Steuwer2, A. Zammit1 1 Department of Metallurgy and Materials Engineering, University of Malta, Msida MSD 2080, Malta 2 Research Support Services Directorate, University of Malta, Msida MSD 2080, Malta
Source:  ICSP14 Milan
Doc ID:  2022075
Year of Publication:  2022
Abstract:  
Abstract This study investigates conventional and duplex shot peening as a means to further improve the fatigue behaviour of austempered ductile iron. This involves characterisation of surface regions through microstructural analysis, phase analysis, and synchrotron radiation stress measurement, amongst other techniques. Additionally, rotating bending fatigue testing revealed that both shot peening variants enhanced the fatigue strength of ADI by 65%. Moreover, duplex shot peening brought about an improvement in fatigue life relative to conventionally shot peened specimens. This was attributed to a reduction in surface roughness of approximately 30% along with amplified magnitudes of compressive residual stresses. Keywords Austempered ductile iron, duplex shot peening, fatigue strength, fractography, strain induced transformation.