Investigation of shot peening effect on titanium alloy affecting surface residual stress and roughness for aerospace applications

Abstract

Titanium (Ti) alloys are used in aviation industry such as engine parts, air frames etc. The main advantage of using Ti alloy is to combat chemical attack in corrosive and hash environment as well as fatigue resistance under cyclic loading conditions. This investigation mainly focuses on how to improve the fatigue resistance of a component thereby the life improvement is envisaged. One of the methods employed is shot peening process, which is a surface phenomenon and introduces compressive residual stress so that the properties like stress corrosion cracking, forming operations, strength get enhanced. The design and experimental work involves the various shot peening parameters such as impact angle, coverage area, Almen intensity levels affecting the surface roughness as well as surface and sub-surface residual stresses. Further, design of experiments involving Taguchi's technique has been discussed at length. The shot peening parameters have been correlated with residual stress and surface roughness parameters. It is also observed that microstructure of the titanium alloy is having the features to support the fatigue properties. Finally the work has been summarized to arise at optimization of these parameters to achieve higher residual stress from the point of higher fatigue life. © 2019 The Authors. Published by Elsevier B.V.