Characterisation of stress concentration features in the alpha+beta titanium alloys

Abstract

The paper explores the impact of texture in the titanium alloy Ti-6-4 on the fatigue response of plain and notched test-pieces. In particular it examines the behaviour of specimens orientated parallel (0 degrees) and perpendicular (90 degrees) to the rolling direction in uni-directionally rolled plate. The measurements clearly demonstrate the importance of basal plane orientation and available basal and prismatic slip systems in determining the observed fatigue lives. For this publication, notch effects are related to a round cylindrical geometry (RCN) with Kt = 1.4. Differences between strain control plain specimens and notches are noted. These are explained through the application of critical strain lifing methods such as Coffin-Manson and Walker. Differences induced by high R values are highlighted