Localized microstructure enhancement via Friction Stir Processing for die cast components

Abstract

Friction stir processing (FSP) is an outgrowth of Friction stir welding (FSW) that locally manipulates
the microstructure by imparting a high level of energy in the solid state resulting in improved mechanical
properties. This study has shown that FSP can be implemented as a post-casting method to locally eliminate
casting defects, such as porosity, which is generated by gas evolution during casting. Coarse second phases are
broken into fine nearly equiaxed particles and uniformly distributed in the matrix. Moreover, grain refinement
is obtained by dynamic recrystallization during FSP. This results in improved microhardness, tensile properties
and fatigue properties of the cast FSP processed A206 alloy. In addition, FSP is a viable means to produce
localized composite structures in cast Al components. Such improvements have important implications
for manufactured components for a variety of automotive and other industrial applications. The convenience
of FSP as a post-processing step that can easily be adapted during machining operation makes it very
attractive to adopt. These results will be reviewed and discussed.