Microstructural evolution in ultrafine-grained titanium processed by high-pressure torsion under different pressures

作者：Wang, Chuan Ting^*; Fox, Alan G.; Langdon, Terence G.

来源：Journal of Materials Science, 2014, 49(19): 6558-6564.

DOI：10.1007/s10853-014-8248-6

• SEVERE PLASTIC-DEFORMATION
• MECHANICAL-PROPERTIES
• AL-MG
• REFINEMENT
• ALLOY
• TI
• BEHAVIOR
• SIZE
• MICROSCOPY
• PRINCIPLES

A grade 2 commercially pure (CP) titanium was processed by high-pressure torsion (HPT) at pressures of 3.0 and 6.0 GPa in order to achieve improved strengths. The microhardness values for these Ti samples were plotted against the imposed strain, and the plots show that a higher saturation microhardness of 320 Hv is achieved for the sample processed at 6.0 GPa compared to a microhardness of 305 Hv when using a pressure of 3.0 GPa. The omega omega-phase has been reported in some earlier HPT investigations of pure titanium, but it was not detected in this investigation even after processing at 6.0 GPa. The absence of the omega-phase is attributed to the relatively high level of oxygen (0.25 wt%) in these CP titanium samples. The higher saturation hardness for the 6.0 GPa sample is consistent with the smaller average grain size of similar to 105 +/- A 12 nm compared with the measured grain size of similar to 130 +/- A 18 nm after processing with an imposed pressure of 3.0 GPa.

• 出版日期2014-10