Evaluation of Peened Aluminum by Positron Annihilation and Residual Stress

Author:  T. Arimoto, K. Oguri, Y. Watanabe, K. Hattori, N. Uesugi
Source:  ICSP-13
Doc ID:  2017051
Year of Publication:  2017
Abstract:  
Introduction: Improvement of fatigue property, i.e. fatigue strength and fatigue life, is a key technology for various structural members of transportation equipment especially in aircraft industries. The weight of fatigue critical parts can be saved by improvement of fatigue property and resulted in better performance of aircraft. Shot peening is the most common conventional technology to improve fatigue property, however, the technology is continuously highly developing today. Recently, for example, novel peening methods such as fine particle shot peening [1], cavitation peening [2], laser peening [3] and ultrasonic peening [4] are being developed and investigated. As the evaluation methods for shot peened materials, intensity measurement by Almen strip, residual stress measurement by X-ray diffraction (XRD) including its depth profile by chemical etching, are applied as standard evaluation methods. Recently, positron annihilation phenomena have been applied to investigate metal surface disorders. And it is revealed that positron annihilation technique is a useful tool to analyze disordered metal crystals, including vacancy interstitial and dislocation etc[5]. K. Ono et al. reported that Doppler broadening of positron annihilation radiation (DBAR) technique, which is one of positron annihilation technique, effectively evaluated the property of conventional shot peening (SP) and fine particle shot peening (FPSP) [6].