Effects of oxygen on phase stability and mechanical properties of quenched Ti-Nb alloys

초록

The effects of oxygen content on microstructures, elastic modulus and tensile properties of quenched Ti-Nb alloys were investigated in order to design a desirable Ti based alloy through casting process. From the microstructural and phase analysis, it is evidently revealed that the volume fraction of beta phase increased with increasing content of oxygen, and the occurrence of intermediate omega phase was suppressed in metastable beta Ti-Nb based alloys. Martensite transformation temperature decreased with increasing content of oxygen. Therefore, it is suggested that oxygen acts to stabilize beta phase rather than a stabilizer in quenched state. Yield strength increased with increasing content of oxygen without a large consumption of ductility in metastable beta Ti-Nb based alloys. The variation of mechanical property was explained by the phase stability, phase formation and microstructure in correlation with oxygen and Nb content.

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