TWI

Local stress-strain curves were determined from an array of spherical indents on the cross-section of the joint of a friction stir welded (FSW) high strength aluminium alloy AA 2198 sheet, in order to characterise the mechanical properties of different zones. A neural network analysis based software was used to identify local stress-strain curves on the basis of locally measured force depth curves, potentially reducing the need for more costly and time consuming experiments on micro-tensile specimens. A 3 mm thickness sheet was used in the experiments to produce FSW butt joints. Sample slotting was carried out on sections taken from the welded joint in order to reduce the residual stresses prior to conducting the indentation experiments. The influence of slotting on the force-depth curve was simulated numerically using FE calculations in order to minimise loss of deformation constraint during indentation. The stress-stain curves derived from the indentation tests were compared to those obtained from micro-tensile tests in order to validate the advantage of the indentation method as a means of quantifying local deformation property variations in FSW- butt joints.

8th International Symposium, 18-20 May 2010, Session 3A: Modelling 1, Paper 01