Modelling Creep Induced by Machining Residual Stresses in Aluminium Alloys

Abstract

Aluminium alloy precision components such as those used in optical systems often experience distortion of their shape during service. This distortion occurs because of residual stresses that are introduced into the surface of the component during machining and lead to creeping of the material when the component is subjected to an elevated temperature for a long time. In this paper, a creep model is developed and used to describe how the residual surface stresses created by milling and by fly cutting affect the geometry of an aluminium alloy component as it creeps. The accuracy of the model is verified by comparing its predictions to measurements made on components manufactured from 4032-O and 6061-T6 aluminium alloys.