Short-Term Heat Treatment of Ti6Al4V ELI as Implant Material.

Phuong Thao Mai,Jens Gibmeier,Therese Bormann,Robert Sonntag,Jan Philippe Kretzer

doi:10.3390/ma13214948

Abstract

Due to its mechanical properties and good biocompatibility, Ti6Al4V ELI (extra low interstitials) is widely used in medical technology, especially as material for implants. The specific microstructures that are approved for this purpose are listed in the standard ISO 20160:2006. Inductive short-term heat treatment is suitable for the adjustment of near-surface component properties such as residual stress conditions. A systematic evaluation of the Ti6Al4V microstructures resulting from short-term heat treatment is presently missing. In order to assess the parameter field that leads to suitable microstructures for load-bearing implants, dilatometer experiments have been conducted. For this purpose, dilatometer experiments with heating rates up to 1000 °C/s, holding times between 0.5 and 30 s and cooling rates of 100 and 1000 °C/s were systematically examined in the present study. Temperatures up to 950 °C and a holding time of 0.5 s led to microstructures, which are approved for medical applications according to the standard ISO 20160:2006. Below 950 °C, longer holding times can also be selected.

Highlights

The average lifetime of an artificial hip joint in a patient can achieve 20 years
The as received material was initially heat treated at 900 ◦ C for 10 min under vacuum followed by oil quenching
It can be concluded for the material state that was initially heat treated at 900 ◦ C for 10 min under vacuum followed by oil quenching and annealed at 500 ◦ C

Summary

Introduction

The average lifetime of an artificial hip joint in a patient can achieve 20 years. Due to demographic developments the number of revision operations is expected to greatly increase [1]. In order to facilitate these revisions, the majority of artificial hip joints are based on a modular construction involving taper junctions. Micromotion occurring at the taper junction can lead to fretting corrosion and to wear at the joint surfaces, which may cause the implant to fail [2,3]. This failure pattern can trigger biological reactions in response to metallic debris. Preventing body fluids from entering the area of contact of the taper junction might lower the susceptibility of the joint materials for galvanic corrosion and increase the corrosion resistance of the taper junction

Objectives

Methods

Conclusion