Residual Stress effect on Fatigue Behavior of 2024- Aluminum alloy


In the present work the effect of residual stress on the fatigue behavior of2024 Aluminum alloy was studied experimentally and numerically usingfinite element method with aid of ANSYS-11 software. All the testspecimens treated by annealing before any process to remove the internalstresses due to cold work. Residual stresses were imparted to the fatigue testsspecimens by heat treatment, pre-strain and welding. X-Ray diffraction wasused to measure the residual stress.The heat treatment; done on the test specimens with different temperature of(420, 450, 480, and 510) oC. After heat treatment; alloy mechanical propertieswere improved. For the heat treated specimens as the temperature increasedthe compressive residual stress increased to (27.06, 41.43, 72.8 and 85.6)MPa. That leads to increase the endurance fatigue limit by (32.93%, 40.48%,50.68% and 61.03%) respectively than other alloy as received. While in prestrain groups; the test specimens loaded to (265, 290, 315 and 340) MPa by atension test machine. As the applied load series were increased thecompressive residual stress increased to (16.51, 25.62, 51.54 and 62.44) MPawhich improve the endurance fatigue limit by (7.68%, 16.19%, 24.98%, and46.45%), respectively. An electrical arc and metal inert gas were used inwelding series to weld the test specimens, that present a tensile residual stressof (76.93 and 72.66) MPa, which reduces the endurance fatigue limit by(23.45% and 16.08%), respectively. The numerical results present fatiguebehavior, deflection and stress at any load, and show a reasonable agreementresults with an experimental one.