Corrosion and biological behavior of nanostructured 316L stainless steel processed by severe plastic deformation

Comprehensive Review on Biomaterials and Their Inherent Behaviors for Hip Repair Applications

Developing biomaterials for hip prostheses is challenging and requires dedicated attention from researchers. Hip replacement is an inevitable and remarkable orthopedic therapy for enhancing the quality of patient life for those who have arthritis as well as trauma. Generally, five types of hip replacement procedures are successfully performed in the current medical market: total hip replacements, hip resurfacing, hemiarthroplasty, bipolar, and dual mobility systems. The average life span of artificial hip joints is about 15 years, and several studies have been conducted over the last 60 years to improve the performance and thereby increase the lifespan of artificial hip joints. Present-day prosthetic hip joints are linked to the wide availability of biomaterials. Metals, ceramics, and polymers are some of the most promising types of biomaterials; nevertheless, each biomaterial has advantages and disadvantages. Metals and ceramics fail in most applications owing to stress shielding and the emission of wear debris; ongoing research is being carried out to find a remedy to these unfavorable responses. Recent research found that polymers and composites based on polymers are significant alternative materials for artificial joints. With growing research and several biomaterials, recent reviews lag in effectively addressing hip implant materials' individual mechanical, tribological, and physiological behaviors. This Review comprehensively investigates the historical evolution of artificial hip replacement procedures and related biomaterials' mechanical, tribological, and biological characteristics. In addition, the most recent advances are also discussed to stimulate and guide future researchers as they seek more effective methods and synthesis of innovative biomaterials for hip arthroplasty application.

Corrosion Behavior of Ultrafine-Grained CoCrFeMnNi High-Entropy Alloys Fabricated by High-Pressure Torsion

The influence of the nanocrystalline structure produced by severe plastic deformation (SPD) on the corrosion behavior of CoCrFeMnNi alloys with Cr contents ranging from 0 to 20 at.% was investigated in aqueous 0.5 M H₂SO₄ and 3.5% NaCl solutions. The resistance to general corrosion and pitting became higher in both the solutions, with higher passivation capability observed with increasing Cr content, and it is believed that the high corrosion resistance of CoCrFeMnNi alloys can be attributed to the incorporation of the Cr element. However, the impact of the nanocrystalline structure produced by SPD on the corrosion behavior was negligibly small. This is inconsistent with reports on nanocrystalline binary Fe–Cr alloys and stainless steels processed by SPD, where grain refinement by SPD results in higher corrosion resistance. The small change in the corrosion behavior with respect to grain refinement is discussed, based on the passivation process of Fe–Cr alloys and on the influence of the core effects of HEAs on the passivation process.