Abstract
An extra-low interstitial near alpha alloy Ti-3Al-2Zr-2Mo(wt％)was fabricated by hydrogenation and thermomechanical consolidation(TMC)of the coarse and spherical pre-alloyed powder with particle sizes of 60 to 270 μm.The coarse powder is a byproduct of pre-alloyed powder produced for selective laser and electron beam additive manufacturing.The TMC process involves powder compaction,fast sintering,in-situ dehydrogenation and an immediate hot extrusion to form a fully dense and fine-grained marten-sitic microstructure.Further dehydrogenation in vaccum at 700℃converted the martensitic microstruc-ture into an interwoven α/β microstructure which exhibited an improved yield strength,apparent neck-ing and premature cracking at grain boundary α(αGB)ribbons.A further annealing of 880℃/1 h/AC led to the formation of a fine-grained α/βt composite structure,which achieved an enhance ultimate tensile strength of 835 MPa and excellent tensile ductility of 16.0％.Analysis of the deformation behavior of the alloy in different states revealed that the α/βt composite structures brought about an enhanced strain hardening capability by heterogeneous deformation effect of hard βt and soft α-laths,which inhibited the formation of microcracks and consequently improved the coordinated deformation.
基金项目
the"Xing Liao Talent Plan"of Liaoning Province,China(XLYC1802080)
中央高校基本科研业务费专项(02080022117003)
NETL
NSTL
维普
万方数据