The improvement of fatigue life in Ti-6Al-4V by ion implantation

Abstract

The alloy Ti-6AI-4V has been implanted with carbon and nitrogen ions. The microstructure produced by these implants is found to contain fine particles of TiC and TiN respectively. Rotating beam fatigue tests show improved fatigue life for both implants, with the superior carbon implantation giving a 20% increase in endurance limit and a factor of 4-5 lifetime increase at higher stresses over unimplanted material. A dose of 1 X 10 17 at./cm 2 is required to obtain the maximum effect. Fatigue cracks have been observed to originate up to 150 Jim below the surface, indicating a complex interaction between the implanted layer and the fatigue failure process.

Evaluating the effects of plasma diffusion processing and duplex diffusion/PVD-coating on the fatigue performance of Ti–6Al–4V alloy

“…In fact, Fig. 3 also includes literature data [30,33,34] for similar tests performed on samples having a mill-annealed microstructure and clearly, the results are inferior to all plasma treated variants. However, irrespective of the initial microstructure, better control of post-treatment cooling rate (from the a + b phase field) may be appropriate in order to optimise bulk microstructure.…”

“…Conversely, for samples which had been triode plasma diffusiontreated and tested in high cycle fatigue subsurface cracking could occur. It has also been reported that differences in the point at which crack initiation is related to the maximum bending stress applied and therefore the duration of the test [33]. More recently, Torres and Voorwald [50] suggested that, in low cycle fatigue, the high tensile load applied will always surpass any compressive residual stress present -thereby favouring surface cracking.…”

Ion implantation of titanium based biomaterials

“…A dose of 1 Â 10 17 ions/cm 2 was required to obtain the maximum effect. Fatigue cracks have been observed to originate up to 150 lm below the surface, indicating a complex interaction between the implanted layer and the fatigue failure process [123]. To combat high temperature (or service) fatigue Pt ion plating of the high temperature titanium alloys is also used [121].…”

Influence of annealing on depth distributions and microstructure of ion-implanted Ti6Al4V

“…INTRODUCTION 20 to 30 nm. [17] Carbon-implanted Ti6Al4V was annealed at different temperatures for 1 hour. [8] The TiC precipitates THE titanium alloy Ti6Al4V is used for load-bearing grow when the temperature exceeds 300 ЊC, reaching sizes components of joint prostheses.…”