Effects of lamellar microstructure characteristics on quasi-static and dynamic deformation behavior of Ti-6Al-4V-4Zr-Mo alloys

The influences of lamellar microstructure characteristics on quasi-static tensile properties and dynamic compression deformation behavior were studied for newly developed titanium alloy Ti-6Al-4V-4Zr-Mo. To tailor the microstructure characteristics, the lamellar microstructure was obtained by be solution treatment at 960°C and underwent subsequent aging treatments at 700 and 570°C, respectively. Results show that as the aging temperature decreases, the size of α colonies and the width of α plates present a declining trend. Correspondingly, the slip length of dislocation becomes relatively shorter, resulting in the increase of quasi-static deformation capability. Dynamic compression tests also show that the lamellar microstructure aged at 570°C with α colonies and α plates in smaller size, which induces the propagated path of crack easily bifurcate and deflect, presents higher dynamic fracture strain, in contrast with the lamellar microstructure aged at 700°C.