Solid-state depositions of multilayer SS304 by friction stir metal deposition

The present work aims to analyse the microstructure and mechanical properties of solid-state depositions of multilayer SS304 by friction stir metal deposition. The microstructure analysis suggests continuous dynamic recrystallization as the main mechanism for grain refinement in the deposited region. The grains at the interface of deposited layers are significantly refined due to severe plastic deformation. Further, the reduction of twin boundary and martensite fractions is noticed in the bulk of the layers. However, strain-induced martensitic transformation is noticed at the interface of the successively deposited regions, due to relatively high stresses owing to lower initial temperatures. The average tensile strength and fracture strain of deposited SS304 is 692 +/- 14 MPa and 87.3 +/- 16%, respectively.

Automated summary

The present study aims to analyze the microstructure and mechanical properties of multilayer SS304 deposited by friction stir metal deposition. Continuous dynamic recrystallization is found to be the main mechanism for grain refinement in the deposited region. The grains at the interface of deposited layers are significantly refined, and the twin boundary and martensite fractions are reduced in the bulk of the layers. However, strain-induced martensitic transformation is observed at the interface of the successively deposited regions due to lower initial temperatures.