TWI

Friction stir processing (FSP) was employed to fabricate oxide dispersion strengthened copper-based composite plates with a graded microstructure and evolving mechanical, thermal, electrical and wear properties along their thickness. Specimens comprised Cu-a1 sheets (thickness 5 mm) with compressed Y2O3 powder filled machined grooves. FSP was conducted using a tool made of tool steel, incorporating a scrolled shoulder and a cylindrical threaded Triflat pin. Three FSP lap runs were performed at a rotational speed of 900 rpm, advancing speed of 40 mm/min and a tool vertical penetration of 3.6-3.7 mm. Friction stir processed sample microstructure was observed by optical microscopy, SEM using secondary or backscattered electrons, energy dispersive X-ray spectroscopy, electron probe microanalysis and X-ray diffraction. Vickers microhardness profiles were determined on transverse cross-sections under a 50 g load. The correlation between early stage microstructure and mechanical properties is discussed.

9th International Symposium, 15-17 May 2012, Session 10B: Non Ferrous, Paper 03