A NEW CLASS OF BETA TITANIUM-BASED ALLOYS WITH HIGH STRENGTH AND GOOD DUCTILITY

摘要

A new class of beta titanium-based alloys having an excellent combination of high yield strength, up to 1650 MPa, with an elongation of 10 % in the aged condition. This alloy can be hot-worked or cold-worked. The hot-working may include forging or hot-rolling which may be conducted at a temperature around beta transus temperature of the alloy. However, maximum strength/ductility combination comes from an as-cast product which is deformed (rolled/forged) at very high temperature ( SIMILAR 1100 DEG C) followed by aging. This gives a slightly cold worked, homogeneous, porosity-free structure of alpha precipitates in a beta matrix. The alloy has a total beta stabilizer content of 20 % to 25 % (weight percent) with no alpha stabilizer. The composition, in percent by weight, is chromium 4 to 7 percent, preferably around 6; copper 3 to 5 percent, preferably 3.5 to 4.5; molybdenum 11 to 13 percent, and balance titanium and incidental impurities.