Titanium alloy heat treatment process, and part thus obtained

摘要

Ti 5-5-5-3 titanium alloy heat treatment process having, in weighted percentages, the following composition:between 4.4 and 5.7% aluminum,between 4.0 and 5.5% vanadium,between 0.30 and 0.50% iron,between 4.0 and 5.5% molybdenum,between 2.5 and 3.5% chromium,between 0.08 and 0.18% oxygen,0.10% traces of carbon,0.05% traces of nitrogen,0.30% traces of zirconium,0.15% traces of silicon,the residual percentage being titanium and impurities, characterised in that the heat treatment of said alloy is carried out by:heating to a first stage of between 810 and 840′° C. and below the β-transus temperature of the alloy;maintaining at the first stage for one to three hours;cooling to a second stage of between 760° C. and 800° C. without intermediate reheating;maintaining at the second stage for two to five hours;cooling to ambient temperature;heating to a third stage of between 540° C. and 650° C.;maintaining at the third stage for four to twenty hours, then cooling to ambient temperature.;Part obtained by this process.