Joint properties of friction welded 6061 aluminum alloy/YSZ-alumina composite at low rotational speed

In this study, a ceramic composite of alumina-yttria stabilized zirconia (YSZ) was friction welded to 6061 aluminum alloy. Alumina rods containing 25 wt.% YSZ were formed using slip casting and subsequently sintered at 1600 °C to form a solid body. The 6061 aluminum alloy sample was cut and polished, and then subjected to friction welding experiments. Both rods were 16 mm in diameter. The results of this study showed that the alumina-25 wt.% YSZ composite was able to be friction welded to 6061 aluminum alloy at a lower rotational speed of 630 rpm compared with high rotational speeds. The friction force was maintained at 5 KN for a frictional time of 30 s. Optical Microscopy (OM) and Field Emission Scanning Electron Microscope (FESEM) were used to analyze the microstructure of the products, particularly at the interface of the joints. The joints were also examined with EDX line and area (energy dispersive X-ray) in order to determine the phases formed during the low speed welding. The mechanical properties including bending strength and Vickers microhardness were measured. The experimental results indicated that the mechanical strength of friction welded alumina-25 wt.% YSZ composite/6061 aluminum alloy components were obviously affected by joining in the low rotational speed (630 rpm), having higher strength as compared to higher rotational speed.