Exploratory Development of Die Materials for Isothermal Forging of Titanium Alloys

摘要

A program was conducted to develop materials for isothermal forging dies exhibiting higher yield strength and creep resistance than currently used nickel-base superalloy and molybdenum alloy compositions. The technical approach involves two phases, the first including alloy development aimed towards improved casting, powder metallurgy and metastable carbide alloy compositions and the second including the fabrication of tooling of the most promising die material/process for the F-15 trunnion drag brace arresting gear. The alloy development study included the evaluation of TRW-NASA VIA, TAZ-8A, IN-792 and IN-100 in terms of tensile, creep rupture and thermal fatigue tests as well as lubricant compatibility tests with typical isothermal forging lubricants. The results indicated that a modified TRW-NASA VIA casting composition offered the greatest potential for applicability as a die material.