Preparation of Boronized Ti6Al4V/HA Composites by Powder Sintering for Dental Applications: Effect of Mixing Method

Three methods, namely, traditional one-step ball milling method, two-step ball milling method, and ball milling-resonant acoustic mixing method were used for mixing the powders of Ti6Al4V, hydroxyapatite (HA), and TiB₂ before sintering at 1050 °C for 30 min to prepare boronized Ti6Al4V/HA composites as dental implants. Their effects on the composition, microstructure, and mechanical properties of the composite were investigated. It was found that compared with traditional one-step ball milling and two-step ball milling method, the ball milling-resonant acoustic mixing method led to lower HA decomposition and better TiB₂ reactivity during subsequent sintering process, which contributed to better mechanical properties. When the powders were mixed by ball milling for 12 h, followed by resonant acoustic mixing for 20 min, the composite obtained after microwave sintering at 1050 °C for 30 min had good comprehensive properties, namely, compressive strength of 331.6 MPa, compressive modulus of 8.69 GPa, and Vickers microhardness of 286.0 HV.