Yield point elongation in fine-grained titanium

Fine-grained (FG) titanium with average grain size of around 1 μm was produced by annealing nano-grained (NG) Ti at 500 °C for different time. The tensile deformation behaviors of this FG Ti were investigated. The phenomenon of yield point elongation (YPE), namely, a plateau following yielding in the stress–strain curve, is observed in FG Ti. It is found that, with increase of the grain size, the YPE in FG Ti appeared and increased to a maximum value, then decreased and, finally disappeared. Microstructures of FG Ti samples before and after the YPE were investigated. The results show that this YPE phenomenon is attributed to the dislocation behaviors and characteristics of grain size in the FG Ti.

► Yield point elongation (YPE) was observed in fine-grained (FG) titanium.
► YPE can be controlled to appear and disappear by adjusting grain size.
► This YPE is attributed to dislocation behaviors and characteristics of grain size.