Extrusion behaviour of AZ91 Mg alloy produced by spark plasma sintering

Abstract

Within a wide project aiming at the production of fully bioabsorbable endovascular stents, cylindrical preforms of the AZ91 Mg alloy produced by SPS were submitted to hot extrusion tests. It has been found that hot extrusion produced a consolidation of the material accompanied by the occurrence of dynamic recrystallisation and a corresponding noticeable grain refinement. The microstructural characterisation revealed that the optimal extrusion conditions were 380°C and 20 mm min⁻¹. Hot compression tests were also carried out to help in the explanation of the extrusion results and, in particular, to evaluate the friction coefficient during extrusion. It has been found that the lubrication should be improved to further optimise the process and obtain a product with superior quality.

Keywords:

• AZ91 magnesium alloy
• Hot extrusion
• Spark plasma sintering

Acknowledgement

The authors gratefully acknowledge the support from Fondazione Cassa di Risparmio di Trento e Rovereto (Trento, Italy).