A Preliminary Study on the Tribological Compliance of Ball and Race Materials for Application in Unlubricated Hybrid Bearings.

Fracture toughness was determined using an IT 5010 hardness tester (Tochpribor JSC) at 200 N load. For softer AISI 52100, AISI 5120, and MMC plates, Rockwell hardness was measured (average of five indents) using a NOVOTEST TS-BRV tester and converted to Vickers microhardness following ISO 18265:2013.