Development of grain structure during friction-stir welding of Cu–30Zn brass

Abstract

High-resolution electron backscatter diffraction was employed to study the evolution of microstructure during friction stir welding of a typical low stacking fault energy material (Cu–30Zn brass) over a wide range of welding temperatures. In all cases, microstructure evolution was found to be governed by discontinuous recrystallization that occurred via grain-boundary bulging and subsequent recrystallization nucleation. This promoted drastic grain refinement and significant strengthening. The crystallographic textures that evolved were typically dominated by a $A/\overline{A}\{111\}<100>$ simple shear texture.

Keywords:

• copper alloys
• friction stir welding
• electron-backscatter diffraction (EBSD)
• microstructure
• texture

Acknowledgements

The authors are grateful to Mr A. Honda for technical assistance and Dr K. Kobayashi for help with EBSD measurements. One of the authors (S. Mironov) would like to express his hearty thanks to Tohoku University for providing a scientific fellowship.