Low cycle fretting and fretting corrosion properties of low carbon CoCrMo and additively manufactured CoCrMoW alloys for dental and orthopedic applications

Abstract

Additive manufacturing (AM) of CoCrMo metallic implants is growing in the orthopedic and dental fields. This is due to the traditional alloy's excellent corrosion resistance and mechanical properties. AM processes like selective laser melting (SLM) require less time, materials, and waste than casting or subtractive manufacturing complex‐geometry structures (bridges, partial dentures, etc.). The objective of this work was to investigate the low cycle tribological and tribocorrosion characteristics of AM CoCrMoW alloys compared to wrought LC CoCrMo (ASTM F‐1537) to assess this AM alloy's performance. Fretting and tribocorrosion testing was performed in air (wear only), PBS (wear + corrosion), and PBS with 10 mM H2O2 (wear + corrosion + inflammation) by a single diamond asperity. No variation between alloys in volume of material removed (p = .12), volume of plastic deformation (p = .13), and scratch depth (p = .84) showed that AM was substantially similar in wear resistance to LC in air and PBS. AM exhibited significantly higher fretting currents (p < .01) at loads up to 100 mN (IAMPBS = 57 nA and IAMH2O2 = 49 nA) than LC CoCrMo (ILCPBS = 30 nA) and (ILCH2O2 = 29 nA). In PBS, wear track depth linearly correlates to fretting current, averaged over 100 cycles. Additionally, fretting currents of both alloys were significantly lower in simulated inflammatory conditions compared to PBS alone. AM alloy has generally similar wear and tribocorrosion resistance to wrought LC CoCrMo and would be ideal for patient specific dentistry or orthopedics where precise, complex geometries are required.

Tribocorrosion of 3D printed dental implants: An overview

“…In addition, the diversity of outcomes highlights the importance of performing the tribocorrosion test for a rigorous characterization of material. Similar to titanium samples, also a CoCrMoW alloy, worked via Laser Metal Fusion, was compared with wrought LC CoCrMo in Mace and Gilbert 172 study. Very close anti-wear responses between them were found, confirming again the additive manufacturing medical tools as valid alternative.…”

Microhardness and Tensile Strength Analysis of SS316L/CuCrZr Interface by Laser Powder Bed Fusion

“…Additive Manufacturing (AM) technology, as a novel manufacturing method, is distinguished by its rapid molding speed, high manufacturing precision, and excellent mechanical properties [ 12 , 13 , 14 ]. Currently, it is employed in a number of fields, including aerospace [ 15 , 16 ], automotive [ 17 , 18 ], biomedical [ 19 , 20 ], and others. In the field of nuclear engineering, numerous industry norms and standards prohibit the utilization of AM components.…”