Fabrication of nanocrystalline austenitic stainless steel with superior strength and ductility via binder assisted extrusion method

Biomedical austenitic stainless steel (ASTM F2581) has been processed by the powder metallurgy technology using binder assisted extrusion method and aside a sintering aid. The resultant microstructure was examined by optical microscopy, field emission scanning electron microscopy, transmission electron microscopy and x-ray diffraction methods. The optical microscopy images indicate that using the binder and sintering aid considerably decreases the porosities of the sintered samples. The x-ray diffraction and transmission electron microscopy images reveal that the microstructure of the sintered alloy consists of austenite in nanocrystalline form and amorphous phases. The mechanical properties were measured through compressive tests. The mean yield strength is estimated at about 824 MPa, and the compressive strength exceeds 1GPa, which is superior to the austenitic stainless steel produced through the conventional methods. Furthermore, the process followed here is compatible with large scale industrial production at a reasonable cost. (C) 2020 Published by Elsevier B.V.

Automated summary

The use of binder and sintering aid significantly reduces the porosity of biomedical austenitic stainless steel, resulting in a microstructure consisting of nanocrystalline austenite and amorphous phases. Mechanical properties such as compressive strength are superior to those produced through conventional methods, and the process is suitable for large scale industrial production at a reasonable cost.