Thin-wall back extrusion of partially remelted semi-solid Sn-Pb

A back extrusion technique was used to study,the isothermal flow behavior of partially remelted Sn-15.6 pet Pb through thin-walled sections Shear rates between 50 and 300 s(-1) were used to produce cylinders with walls ranging from 1 to 2.5 mm in: thickness. Back extrusion was found to be an unsuitable technique for characterizing the rheological behavior of high solid fraction semi-solid material through thin-walled sections. Inhomogeneous flow occurred, with the extruded product having a higher fraction of liquid than the original nonextruded sample. The fraction of liquid in the wall of the extruded product was found to be a function of the extrusion ratio, increasing with decreasing wall thickness.