Metallurgical investigation of a failure in 316L stainless steel orthopaedic implant

An orthopaedic implant (nail for shinbone) made of 316L stainless steel (SS) that failed prematurely was examined to determine the root cause for the fracture. Detailed scanning electron microscopy was carried out to conclusively establish the evidence(s). Based on the results of extensive fracture surface analysis as well as the background information provided on the implant, it was determined that the implant (stainless steel nail) failed by the mechanism of predominantly ductile fracture facilitated by the presence of non-metallic inclusions.