Influence of heat treatment conditions on microstructure of ti-6al-7nb alloy as used surgical implant materials

Abstract EN

The study involves mechanical deformation and heat treatment effect on the microstructure of the Ti-6 Al-7 Nb alloy which is used as surgical implanted materials.

The observed properties of (alpha-beta) Ti-based alloy are strongly dependent on their microstructures.

These alloys are heat treated by solution treatment and aging (STA) as an effective strengthening method for (alphabet) titanium alloys.

Ti-6 Al-7 Nb alloy is hot rolled in the (alpha-beta) field and subjected to solution treatment above and below its beta transformation temperature.

The solution treatments are applied at three different temperatures (850oC, 930oC and 950oC) for one hour to these treatments.

The solution treatment specimens are water quenched (WQ), normalizing [air cooled (AC) and annealed, [furnace cooled (FC)] and subsequently aged the quenched and normalized specimens at 550oC for 4 hours.

Changes in the microstructure were observed from heat treatment action using optical microscopy, Atomic Absorption Spectroscopy (AAS) and phase's analysis by X-ray diffraction (XRD).

The microstructure examination results for as received alloy indicate alpha grains within a b- transformed matrix.

The results also indicate that the grain size and percent of a / b for the heat treated specimens depend on heat treatment type and cooling media.

The microstructure of specimens heat treated at 950oC with air cooled shows fine duplex (a / b) structures which have excellent properties for surgical implanted field applications.