Investigation the Creep-Fatigue Behavior and A.C. Electrical Conductivity of AA 6061 Under Ultrasonic Peening
Engineering and Technology Journal,
2019, Volume 37, Issue 11A, Pages 453-459
AbstractUltrasonic peening is an innovative surface improvement process used to increase the resistance of aircraft metals and enhance high cycle fatigue life. The process creates residual compressive stresses deep into part surfaces. These compressive surface stresses inhibit the initiation and propagation of fatigue cracks. Aluminum alloys are relatively new materials used in aerospace, marine, automobile, and bridges due to low weight, which has significant advantages compared to the other materials. A major concern in the design of Aluminum alloys subjected to variable loads is fatigue strength and life. In this paper mechanical properties, fatigue strength, fatigue life and A.C.. electrical conductivity were studied for AA6061-T6 to assess the effects of ultrasonic peening (UP) on mechanical properties, fatigue at room temperature (RT), creep-fatigue (CF) at 250 ͦC and A.C.. electrical conductivity. Test results showed that after UP, the mechanical properties; ultimate tensile strength (UTS) and yield stress (Ys) were noticeably improved. The improvements in UTS and Ys were enhanced by 5.7% and 1.5% respectively while the ductility was reduced from 16.5% to 15.7%. Fatigue strength was enhanced by 8.37% compared to strength at RT. The results of UT before creep-fatigue CF showed increasing in fatigue strength 147 MPa at CF 250 ̊C and improved to153 MPa after applying UP, indicating 4% improvement in strength. The fatigue life was improved after UP for both RT and CF. It was found that the A.C. electrical conductivity increase as the frequency increase for all the cases above.
 R.L. Elwin, “Introduction to Aluminum and
Aluminum Alloys,” ASM International, Metals
Handbook, Tenth Edition, Vol. 2, pp. 3-14, 1990.
 H.S. Zahra, “The Effect of AL2O3 Nanomaterials
on Fatigue Behavior of 7075 Al-alloy,” MSc Thesis,
Material Engineering Dept., Univ. of Al-Mustansiriya,
 Z.M. Elimat, “Study of A.C. Electrical Properties
of Aluminum –Epoxy Composites,” Journal of Physics
D: Applied Physics, Vol. 41, No. 16, pp. 7, 2008.
 R. Ramos, N. Ferreira, J.A.M. Ferreira, C. Capela
and A.C. Batista, “Improvement in Fatigue Life of Al
7475-T7351 Alloy Specimens by Applying Ultrasonic
and Microshot Peening,” International Journal of
Fatigue, Vol. 92, Part 1, pp. 87-95, 2016.
 H.J. Al-Alkawi, H.M. Amer and F.N. Saba,
“Enhancement of Cumulative Corrosion-Fatigue
Interaction Lives of AA6061-T6 Aluminum Alloy
using Impact Peening Process,” JESD, Vol. 21, No. 0,
 S.H. Shaker, N.H. Mohsin and M.A. Raad, “Effect
of Ultrasonic Peening Technique on Fatigue Life of
6061-T6 Aluminum Alloy,” Al-Qadisiyah Journal for
Engineering Sciences, Vol. 10, No. 2, pp. 171-179,
 D., M., Vanini and S.A. Sadough, “Corrosion
Fatigue Enhancement of Welded Steel Pipes by
Ultrasonic Impact Treatment,” materials letters, Vol.
39, pp. 462-466, 2015.
 D., Chengli, “Low Cycle Fatigue, Creep and
Creep-Fatigue Interaction Behavior of a TiAl Alloy at
High Temperatures,” Scripta Materialia, Vol. 144, pp.
 S. Sabah, “The Effect of Aluminum Oxide
Nanoparticles on Dielectric Properties of Polyvinyl
Alcohol,” Journal of Industrial Engineering Research,
Vol. 1, No. 2, pp. 13-16, 2015.
 T. Bashir, A. Shakoor, E. Ahmed, N.A. Niaz, I.
Shahid, S.A. Muhammad and A.M. Mohammad,
“Magnetic, Electrical and Thermal Studies of
Polypyrrole-Fe2O3 Nanocomposites,” Polymer
Science, Series A, Vol. 59, No. 6, pp. 902-908, 2017.
 M.H. Abdallah, Y. Alramadin, M. Ahmed, A.
Zihlif, S. Jawad and A. Alnajjar, “Electrical
Characterization of Metal Fiber-Polyester Composite,”
Inter. J. of polymeric materials, Vol. 37, pp. 33-42,
 J.R. Davis, “Aluminum and Aluminum Alloy,”
ASM International, pp. 351- 416, 2001.
 N.I.I. Mansor, S. Abdullah, A.K. Ariffin and J.
Syarif, “A review of The Fatigue Failure Mechanism
of Metallic Materials under a Corroded Environment,”
Engineering Failure Analysis, Vol. 42, pp. 353-365,
 R. Hales, “A Quantitative Metallographic
Assessment of Structural Degradation of Type 316
Stainless Steel During Creep-Fatigue,” Fatigue &
Fracture of Engineering Materials & Structures, Vol.
3, No. 4, pp. 339-356, 1980.
 X.L. Yan, X.C. Zhang, S.T. Tu, S.L. Mannan,
F.Z. Xuan and Y.C. Lin, “Review of Creep–Fatigue
Endurance and Life Prediction of 316 Stainless
Steels,” International Journal of Pressure Vessels and
Piping, Vol. 126, pp. 17-28, 2015.
 S.F. Abdul Jabbar, “Shot Peening and FatigueCreep Interaction Under Variable Amplitude Stresses
of Different Aluminum alloys,” Ph.D. Thesis,
Mechanical Engineering Department, University of
Technology, Baghdad, Iraq, 2012.
 Device manual, 2014. Available:
 E. Statnikov, O.V. Korolkov and V.N. Vityazev,
“Physical and Mechanism of Ultrasonic Impact
Treatment,” Applied Ultrasonics, Vol. 44, pp. e533-
 K.P. Donnelly and B.R. Varlow, “Nonlinear DC
and A.C. Conductivity in Electrically Insulating
Composites,” Dielectrics and Electrical Insulation,
Vol. 10, pp. 610-614, 2003.
- Article View: 152
- PDF Download: 95