Abstract
Previous results on β quenched Ti-215%(mass%) Fe alloys suggested that the volume fraction of athermal ω phase (ωath) was maximum in the Ti-5%Fe alloy. In present work, influence of Al addition to the Ti-5%Fe alloy on the formation of ωath has been investigated by resistivity and hardness measurement, X-ray and electron diffractometry in the β quenched state.
In alloys containing up to 8%Al, optical microscopy reveals single phase structure, and only β phase is detected by X-ray diffraction.
Resistivity monotonously increases with Al content. Resistivity ratio between liquid nitrogen and room temperature, ρLN/ρRT, shows a maximum at 6%Al, at which hardness shows a minimum.
Room temperature electron diffraction pattern due to athermal ω phase is changed by the Al addition from clear spots to diffuse scattering.
Similarly as the case of Ti-20V-Al, it is considered that the added Al dissolves substitutionally into β Ti-5%Fe lattice, lowers starting and finishing temperatures of athermal ω phase formation, ωS and ωf, and then decreases volume fraction of athermal ω phase at room temperature.
