Fatigue Property Enhancement By Fine Particle Shot Peening For Aircraft Aluminum Parts

Author:  A.Inoue, T. Sekigawa and K. Oguri
Source:  Conf Proc: ICSP-10 Tokyo, Japan 2008
Doc ID:  2008074
Year of Publication:  2008
Abstract:  
ABSTRACT Fine Particle Shot Peening (FPSP), which has been developed in the Japanese automobile industry for steel parts, enables to improve fatigue property much more than the conventional Shot Peening (SP). The suitable FPSP process for the aluminum aircraft parts is under development. Fatigue life of conventional shot peened 7050-T7451 aluminum parts was increased by several times, while that of fine particle shot peened aluminum was increased by more than ten times compared with that of as machined. Compressive residual stress on fine particle shot peened surface which was covered with uniform dimples adequately is higher than that on shot peened surface. Fracture surface observation revealed that the fatigue crack of fine particle shot peened samples originate at the subsurface layer, which shows the high compressive residual stress at very near the surface and less roughened surface prevent crack initiation from the surface. Then FPSP can improve fatigue life farther more than SP does, which shows fatigue crack initiates from a small flaws and laps on the surface created by SP. KEY WORDS Fatigue enhancement, Fine Particle, High velocity, Aircraft, Smooth surface