Effect of microstructure on mechanical, electrochemical, and biological properties of Ti/HA surface composites fabricated by FSP method

Abstract

This study investigated the effect of microstructure on the mechanical, electrochemical, and biological properties of Ti/HA surface composites fabricated using the FSP method. The microstructure was altered by various traverse speeds of 30–75 mm/min. Microstructural studies revealed that lower traverse speeds (30–45 mm/min) resulted in fewer defects like voids and cracks compared to higher speeds (60–75 mm/min). A more heterogeneous distribution of HA particles in the Ti matrix was observed at higher traverse speeds due to a higher stirring effects and cooling rates. Mechanical investigations showed that ultimate tensile strength decreased with increasing traverse speed. The values for samples at 30, 45, 60, and 75 mm/min were obtained as 855 MPa, 746 MPa, 754 MPa, and 542 MPa, with a ± 4% standard deviation respectively. Electrochemical tests showed that the corrosion resistance decreased with increasing traverse speed due to more pitting corrosion occurring specifically at the interfaces between Ti/HA phases. All samples exhibited high biocompatibility, but cell viability was highest in the sample produced at a speed of 75 mm/min which had a higher amount of defects and surface agglomeration of HA particles affecting cell growth and proliferation. These findings demonstrate how processing conditions can significantly impact material properties including susceptibility to localized forms of corrosion as well as cell response over time.