Dislocation network mediated grain boundary engineering in an additively manufactured titanium alloy

Continuous grain boundary α (CGB-α) usually causes degradation of mechanical properties in titanium alloys. Here, we propose to employ dislocation network in an additively manufactured titanium alloy for GB engineering to suppress CGB-α. A C-bearing titanium alloy was selectively laser melted to produce homogeneously distributed TiC flakes and a dislocation network that links them to GBs. Upon solution treatment, the dislocation network promotes dissolution of intragranular carbides and formation of discrete GB TiC particles. These GB carbides suppress the formation of CGB-α during ageing treatment, which together with the formation of high-density intragranular α leads to excellent strength-ductility synergy.