Evolution of nano-scaled lamellae and its effect on strength of Ti–Ta composite

Highlights: • Fine Ta powders can be preserved after proper spark plasma sintering process. • The nano-scaled lamellae occur during the rolling process. • The interfaces of lamellae can obstruct dislocation slip. • The Ti–Ta composite with nano-scaled lamellae exhibits excellent mechanical properties. Introduction of nanoscale lamellae is an efficient way to improve the mechanical performance of alloys/composites. Here, we present a convenient and available approach to introduce nanoscale metallic lamellae into Ti–Ta based composites via spark plasma sintering and subsequent hot rolling. The formed lamellae originate from ultra-fine Ta powder with the particle size of less than 2 μm. Ti–Ta nanoscale lamellae consist of alternating Ti- and Ta-enriched lamellae with a body-centered cubic interface resulting from the effect of partial diffusion, as revealed by transmission electron microscopy. The nanoscale lamellae can significantly impede the motion of dislocations and thus effectively improve the strength of the Ti–Ta composite. The strength enhanced by nanoscale lamellae reaches up to 136.18 MPa when the total deformation degree is 60%. The manufacturing route developed here is versatile, capable of making high performance composites with nanoscale lamellae.