Residual stress measurements in laser processed aluminium alloys

Two aluminium alloys (2014 and 7075) have been treated by laser irradiation to investigate their corrosion resistance. Surface melted layers to depths of 300–500 μm using a CO2 laser have been produced on both of the alloys. The corrosion resistant characteristics of the alloys after laser surface melting are mainly affected by local changes in composition and microstructure. However, another important factor that can affect corrosion resistance is the presence of residual stresses that occur as a result of the rapid solidification of the melted layer. Tensile residual stresses are deleterious to corrosion resistance whilst compressive residual stresses can help to enhance the corrosion resistance.The residual stresses have been measured using multi-exposure x-ray diffraction techniques on single melt tracks and multiple passes covering larger areas. The effect of altering the laser processing parameters on the residual stress has also been investigated to determine correlation of the corrosion resistance...