The dynamic response of Ti521, a titanium alloy for impact containment: Rate dependency and the influence of cooling processes

Ti521, a titanium alloy with a tailored composition that provides an excellent balance of strength and ductility, was developed and manufactured. The effects of cooling rate on both quasi-static and dynamic mechanical behaviour were investigated. An extensive experimental campaign was undertaken to characterise the rate dependent properties of Ti521 and to evaluate the influence of manufacturing parameters on its mechanical performance. The alloy exhibited the highest yield strength under rapid cooling conditions, with values exceeding those of Ti6Al4V. Furthermore, the analysis of the energy dissipated during plastic deformation indicates that Ti521 has strong potential to outperform Ti6Al4V in impact containment applications. A novel experimental methodology, incorporating multiple camera setups, was introduced and employed to characterise anisotropy induced by variations in cooling rates and rolling directions. This approach enabled the accurate evaluation of the true stress-strain response in the presence of anisotropy and, consequently, the influence of rolling direction on the mechanical performance of the alloy. Cross rolled specimens exhibited no measurable anisotropic behaviour, whereas unidirectionally rolled material showed slight differences in mechanical properties between the rolling and transverse directions. • A novel titanium alloy, Ti521, shows higher energy absorption compared to Ti6Al4V. • The mechanical processing introduced significant anisotropy in the material. • A method for high-rate testing, including dual high-speed imaging is presented. • Cooling rates and processing influence the balance of strength and ductility. • At high strain rates ductility becomes the dominant factor for impact resilience.