Biocompatibility and cyclic fatigue response of surface engineered Ti6Al4V femoral heads for hip-implant application

A major problem with femoral head (FH) for hip implant (HI) applications is that it often fails in service. As a result, revision surgery becomes a must. The related trauma is tremendous for the patient, especially the aged ones. This also implies additional expenses. Keeping these aspects of the problem in view, here we report the development of wear, corrosion and fatigue resistant Ti6Al4V alloy based FH; by a duplex surface engineering (DSE) technique. Thus, the DSE based FHs are developed by a novel combination of plasma nitriding (PN) and Ti/TiN multilayer coating (MLC). The MLCs are formed by magnetron sputtering technique. The Ti6Al4V based FHs are called Ti. The only plasma nitrided FHs are called TiPN. The DSE based FHs are called TiPNML. The corrosion resistances are studied in hank's solution. The sliding wear resistance is studied in simulated body fluid (SBF). The biocompatibilities are studied by the standard MTT assay technique. The cyclic fatigue resistance behaviour up to one million walking cycles is studied in SBF in a HIP simulator with the UHMWPE acetabular cups used as the counter bodies in articulation. The results of the corrosion, biocompatibility, wear, and cyclic fatigue resposnses clearly reveal that the performances of the TiPNML and TiPN FHs are much better than that of the Ti based FHs. The reasons behind such spectacular improvement in biocompatibility as well as corrosion, wear and fatigue resistance are explained in terms of the prevalent phases, microstructural factors, wear mechanisms and surface roughness. The implications of the current results in terms of futuristic FH developments for HI applications are discussed. Such futuristic FH development could provide better HI. These prospects would minimize HI failure and hence, revision surgeries. Thus, the related trauma for numerous patients; especially the aged ones; could be significantly reduced

Bio-tribological response of duplex surface engineered SS316L for hip-implant application

Here we report on intelligently planned duplex surface engineering concept that utilizes a combination of plasma nitriding and multi-layering for optimizing cyclic fatigue resistance. This new concept of duplex surface engineering treatment is utilized to achieve improvement in cyclic fatigue as well as bio-tribological response of SS316L (SS) based hip-implants. The samples are SS316L (SS), Ti/TiN multi-layer-coated SS i.e., SSML and Ti/TiN multi-layer-coated plasma nitrided SS i.e., SSPNML. The samples are characterized by XRD, FESEM, TEM, nanoindentation, micro-scratch and sliding wear. In addition, cyclic fatigue behaviour up to 1 million cycles of SS and SSPNML femur heads against UHMWPE acetabular cups are studied using a hip simulator. The results prove that under comparable conditions, the nanohardness, micro-scratch resistance and sliding wear resistance of the SSPNML samples in SBF are much better than those of the corresponding SSML and SS samples. Further, as compared to the SS femoral head, the SSPNML femoral head is found to be much more resistant to cyclic fatigue. These results establish beyond doubt the superiority of the duplex surface engineering treatment utilized in the present work to achieve superb cyclic fatigue resistance in SS based femoral heads for bio-prosthetic hip implants

Nanotribological response of a plasma nitrided bio-steel

AISI 316L is a well known biocompatible, austenitic stainless steel (SS). It is thus a bio-steel. Considering its importance as a bio-prosthesis material here we report the plasma nitriding of AISI 316L (SS) followed by its microstructural and nanotribological characterization. Plasma nitriding of the SS samples was carried out in a plasma reactor with a hot wall vacuum chamber. For ease of comparison these plasma nitrided samples were termed as SSPN. The experimental results confirmed the formations of an embedded nitrided metal layer zone (ENMLZ) and an interface zone (IZ) between the ENMLZ and the unnitrided bulk metallic layer zone (BMLZ) in the SSPN sample. These ENMLZ and IZ in the SSPN sample were richer in iron nitride (FeN) chromium nitride (CrN) along with the austenite phase. The results from nanoindentation, microscratch, nanoscratch and sliding wear studies confirmed that the static contact deformation resistance, the microwear, nanowear and sliding wear resistance of the SSPN samples were much better than those. of the SS samples. These results were explained in terms of structure property correlations. (C) 2016 Elsevier Ltd. All rights reserved

Abstracts of National Conference on Research and Developments in Material Processing, Modelling and Characterization 2020

This book presents the abstracts of the papers presented to the Online National Conference on Research and Developments in Material Processing, Modelling and Characterization 2020 (RDMPMC-2020) held on 26th and 27th August 2020 organized by the Department of Metallurgical and Materials Science in Association with the Department of Production and Industrial Engineering, National Institute of Technology Jamshedpur, Jharkhand, India. Conference Title: National Conference on Research and Developments in Material Processing, Modelling and Characterization 2020Conference Acronym: RDMPMC-2020Conference Date: 26–27 August 2020Conference Location: Online (Virtual Mode)Conference Organizer: Department of Metallurgical and Materials Engineering, National Institute of Technology JamshedpurCo-organizer: Department of Production and Industrial Engineering, National Institute of Technology Jamshedpur, Jharkhand, IndiaConference Sponsor: TEQIP-