Application of Friction Stir Processing (FSP) as a Cladding Method to Produce AA2024-AA1050 Multi-layer Sheets

Friction stir processing (FSP) was used as a cladding method for the fabrication of a AA2024 clad layer on a AA1050 sheet. Crossover multi pass FSP with 50% overlap was considered as the cladding method. Effects of the number of FSP passes and post heat treatment on the microstructure and properties of clad layers were evaluated. Microstructural evolutions during the FSP and heat treatment were investigated by field emission scanning electron microscopy (FESEM). The results showed that a defect free clad layer and a uniform metallurgical interface between the clad layer and base material can be achieved by the FSP. Moreover, clad layers exhibited higher hardness values in comparison to the base material. T4 Heat treatment of the FSPed samples resulted in comparatively high hardness values after natural aging. The highest hardness value of about 160 HV was achieved after heat treatment of the sample obtained from 3 intersecting FSP passes. Tensile strength of clad layers increased to 317 MPa after three intersecting FSP passes, compared to about 70 MPa of Al substrate.