Determination of elastic/plastic behavior of hydroxyapatite coatings on titanium implants

There is little knowledge about elastic/plastic deformation behavior of hydroxyapatite (HA) coatings on implant substrates, even though such information is valuable for mechanical stability of the HA coated implants. Note that elastic/plastic behavior of HA coatings cannot be obtained from tests of their bulk counterparts due to the well-known size effects on mechanical strength. The objective of the present study is to estimate the elastic/plastic constitutive relation of plasma sprayed HA coatings on Ti alloy substrates using a novel approach that combines the indentation tests and the non-linear finite element method. The work demonstrates that constitutive relation can be obtained by numerically simulating the indentation stress/strain curves of HA coatings.