Structure–properties’ modification of 70/30 brass by large-load and low-speed friction stir processing

Abstract

A novel one-step approach named large-load and low-speed friction stir processing was developed to produce an ultrafine-grain structure in 70/30 brass. The material so processed was characterised by a mean grain size of 0.5 µm and high angle boundaries of 91%. Abundant twin boundaries and stacking fault were produced in the grains as well. The grain refinement mechanism is attributed to the combination of discontinuous dynamic recrystallisation (DRX), microshear bands assisted DRX and twinning-induced DRX. A good combination of yield strength and uniform strain was achieved. This study provides a simple and effective method to improve the microstructure and mechanical properties in metals and alloys with low stacking fault energy.

Through-thickness microstructure and mechanical properties in stationary shoulder friction stir processed AA7075

“…This thermo-mechanical deformation produces the stir zone (SZ) with fine-grained microstructure due to dynamic recrystallization. FSP has been demonstrated for different applications such as grain refinement and subsequently properties enhancement [4][5][6][7]. The heat input during FSP governs microstructural features and hence resultant properties.…”

Friction stir processing of a cast manganese-aluminum bronze for improving corrosion and cavitation erosion resistances

“…FSP is developed based on the principle of friction stir welding (FSW) [11], and it realizes the surface modification by virtue of heat input and severe plastic deformation induced by a stirring tool. FSP has been applied to refine the microstructure and enhance the mechanical properties of Al alloys [12], Mg alloys [13], steels [14] and copper alloys [15], and fabricate surface composite to improve the corrosion resistance of Mg alloy [16]. Compared with the above laser surface melting/alloying and gradient layer methods, a much thicker modified layer can be fabricated by FSP.…”