The effect of controlled shot peening on the fatigue behaviour of 2024-T3 aluminium friction stir welds

Abstract The work examines the microstructural and fatigue properties of friction stir welds made of 2024-T3 aluminium alloy and provides extensive information towards their cyclic stress–strain behaviour, residual stress distribution and crack initiation sites. To eliminate the cost associated with the removal of the flow arm by milling and other costs associated with the quality control of the welding process (residual stress distribution, micro-hardness profile, welding scar, etc.), controlled shot peening is introduced. Tensile residual stresses introduced in the thermomechanical affected zone during welding are found to become compressive after peening. The effect can be held responsible for increasing the fatigue resistance of the weld beyond the values of the bare (parent) material.

[1]  C. A. Rodopoulos,et al.  Optimisation of the fatigue resistance of 2024-T351 aluminium alloys by controlled shot peening-methodology, results and analysis , 2004 .

[2]  R. Sandström,et al.  Fatigue of Friction Stir Welded AlMgSi-Alloy 6082 , 2000 .

[3]  M. W. Mahoney,et al.  Properties of friction-stir-welded 7075 T651 aluminum , 1998 .

[4]  Kumar V. Jata,et al.  Friction-stir welding effects on microstructure and fatigue of aluminum alloy 7050-T7451 , 2000 .

[5]  C. Dalle Donne,et al.  Effects of Weld Imperfections and Residual Stresses on the Fatigue Crack Propagation in Friction Stir Welded Joints , 2000 .

[6]  Richard G. Pettit,et al.  Validated Feasibility Study of Integrally Stiffened Metallic Fuselage Panels for Reducing Manufacturing Costs , 2000 .

[7]  Phil E. Irving,et al.  The role of residual stress and heat affected zone properties on fatigue crack propagation in friction stir welded 2024-T351 aluminium joints , 2003 .

[8]  G. Bussu.  Damage tolerance of welded aluminium aircraft structures , 2000 .

[9]  Lawrence E Murr,et al.  Microstructural issues in a friction-stir-welded aluminum alloy , 1998 .

[10]  Gary R. Halford,et al.  Investigation of residual stress relaxation under cyclic load , 2001 .

[11]  L. Murr,et al.  Friction-stir welding of magnesium alloy AZ31B , 2002 .

[12]  E. R. Rios,et al.  Analysis of the effects of controlled shot peening on fatigue damage of high strength aluminium alloys , 2003 .

[13]  I. Altenberger,et al.  Alternative Mechanical Surface Treatments: Microstructures, Residual Stresses & Fatigue Behavior , 2006 .

[14]  C. Donne,et al.  Fatigue and Fracture Performance of Friction Stir Welded 2024-T3 Joints , 1998 .

[15]  H. Kokawa,et al.  Distribution of tensile property and microstructure in friction stir weld of 6063 aluminum , 2001 .

[16]  P. J. Webster,et al.  Synchrotron X-ray residual strain scanning of a friction stir weld , 2001 .

[17]  M. R. James.  The Relaxation of Residual Stresses During Fatigue , 1982 .

[18]  P. J. Webster,et al.  Residual Stress in a Friction Stir Welded Al Extrusion , 2000 .

[19]  A. Levers,et al.  Theoretical Analysis of Beneficial and Detrimental Effects of Controlled Shot Peening in High Strength Aluminium Alloys , 2006 .

[20]  L. Murr,et al.  Microstructures in Friction-Stir Welded Metals , 1998 .

[21]  Ian Sinclair,et al.  Fatigue of Friction Stir Welded 2024-T351 Aluminium Alloy , 2002 .

[22]  Philip J. Withers,et al.  Residual Stress Field in a Friction Stir Welded Aluminium Extrusion , 2000 .

[23]  B. Skrotzki,et al.  Microstructural and Mechanical Characterization of a Friction Stir Welded Al-Alloy , 2000 .

[24]  Murray W. Mahoney,et al.  Effects of friction stir welding on microstructure of 7075 aluminum , 1997 .