| Title |
Microstructure and Tensile Properties of Ultra-Fine Grained Pure-Ti |
| Authors |
고영건(Young Gun Ko); 염종택(Jong Taek Yeom); 신동혁(Dong Hyuk Shin); 이종수(Chong Soo Lee) |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
Pure-Ti; Ultra-fine grain; Dislocation bow-out; Strain hardening; Dynamic recovery |
| Abstract |
A study was made to investigate microstructural evolution and mechanical properties of ultra-fine grained (UFG) pure-Ti produced by equal channel angular (ECA) pressings. The deformed structures were analyzed by finite element method and transmission electron microscopy with the increment of straining. After 4 isothermal ECA pressings, initial coarse grains (30 μm) were significantly refined to ~0.3 μm with homogeneous distribution of microstructure which was resulted from 180˚ rotation of the sample between pressings. UFG pure-Ti exhibited the considerable improvement in yield strength while losing strain hardening capacity as compared to coarse grained microstructure at ambient temperature, which was mainly attributed to ultra-fine grain microstructure with non-equilibrium grain boundaries. Such high strength and unusual strain hardening behavior of UFG pure-Ti were discussed in relation with two dislocation models based on dislocation bow-out and dynamic recovery associated with trapped lattice dislocations. |