Abstract
This study investigates the influence of titanium (Ti) additions (0.5–3 wt.%) on the microstructural evolution and mechanical properties of ZA27 alloys. Microstructural analysis of the ZA27 alloy via optical microscopy, scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) revealed that Ti significantly refines the primary α-Al phase, inducing a transition from coarse dendritic morphology to a fine rosette-like structure. At higher Ti concentrations, the precipitation of Ti-rich intermetallic phases, including (TiAl, CuTi₂, TiZn₃), was confirmed. Mechanical characterization showed a substantial improvement in both hardness and tensile strength; Vickers microhardness increased from 122.7 HV to 159.8 HV for the ZA27alloy and the 3% Ti-modified ZA27 alloy, respectively. Additionally, the ultimate tensile strength (UTS) rose from 146.3 MPa for the ZA27 alloy to 265 MPa for the 3% Ti-modified.ZA27 alloy. These enhancements were achieved alongside a favourable reduction in overall density and porosity, thereby leading to a remarkably high specific strength, which directly optimizes the performance of ZA27 alloys in lightweight engineering applications.