STRENGTHENING MECHANISMS DURING THE HEAT TREATMENT OF THREE TITANIUM ALLOYS - TI-6AL-4V, TI-6AL-6V-2SN, AND TI-8AL-1MO-1V.
Abstract:
The effects of solution and aging treatments on the Alloys Ti-6Al-4V, Ti-6Al-6V-2Sn, and Ti-8Al-1Mo-1V were investigated by hardness measurements, electron microscopy, resistance measurements at the aging temperatures, and X- ray diffraction. Relatively small changes in alloy content have a marked effect on the strengths attainable by heat treatment. Two hardening mechanisms account for all the observed responses to heat treatment. These mechanisms are the decomposition of the transformed beta phase either during the quench from the solution temperature or as the result of subsequent aging and the precipitation of aluminum-rich alpha-2 in the primary alpha phase. The changes in strength as the result of heat treatment are correlated with the equilibrium alloy contents of the phases present at the solution temperature.