ABSTRACT

Water jet peening is a surface modification technique which can introduce compressive residual stresses beneath the surface of the engineering components. In this paper, the effects of water jet peening process, in the absence of abrasive materials on residual stresses, surface roughness, and fatigue life of the aluminium alloy 7020 samples were numerically and experimentally investigated. Therefore, two nozzles with respective exit angles of 0° (round nozzle) and 20° (orifice nozzle) were used and residual stresses were measured through centre-hole drilling technique. Furthermore, fatigue tests were performed on the water peened samples. Results indicated that in contrast to the horizontal speed of the nozzle, pressure of source and stand-off distance exerted a profound influence on the magnitude of residual stresses and surface roughness. Moreover, in cases which the pressure of the source exceeded a certain limit, fatigue life of the workpiece declined due to the surface crack formations.

摘要

喷水喷丸是一种表面改性技术，可以在工程部件的表面下方引入压缩残余应力。本文通过数值和实验研究了在没有磨料的情况下水射流喷丸工艺对7020铝合金样品的残余应力，表面粗糙度和疲劳寿命的影响。因此，使用两个出口角度分别为0°（圆形喷嘴）和20°（孔口喷嘴）的喷嘴，并通过中心孔钻孔技术测量残余应力。此外，对水喷丸样品进行了疲劳测试。结果表明，与喷嘴的水平速度相反，源的压力和支座距离对残余应力的大小和表面粗糙度产生了深远的影响。