13th International Conference on Fracture June 16–21, 2013, Beijing, China -4- 104 105 106 107 108 50 100 150 200 250 300 350 RB Drawn RB Extruded In 85% US Extruded US Drawn US:Ultrasonic loading RB:Rotating bending Number of cycles to failure, Nf (cycle) Stress amplitude σa (MPa) 104 105 106 107 108 50 100 150 200 250 300 350 RB Extruded RB Drawn In 25% US:Ultrasonic loading RB:Rotating bending Stress amplitude σa (MPa) Number of cycles to failure, Nf (cycle) US Extruded US Drawn (a) In RH25% (b) In RH85% Figure 3. S-N curves of extruded and drawn Al alloys Figure 4. Crack growth curves of extruded and drawn Al alloys 0 1x105 2x105 3x105 4x105 5x105 6x105 0.01 0.1 1 10 σ a =230MPa Ultrasonic loading Crack length, λ (mm) Number of cycles, N (cycle) Extruded in 25% Drawn in 25% Extruded in 85% Drawn in 85%
RkJQdWJsaXNoZXIy MjM0NDE=