Effect of the Method of Production of TiAl-Based Layered Composite Billets Containing a Ductile Constituent on the Structure of Rolled Sheets

摘要

The effect of the method of production of TiAl-based layered composite billets intended for hot rolling on the structure of rolled sheets is studied. The billets consist of (gamma-TiAl + alpha_2-Ti_3Al)/ductile metallic constituent (DMC) materials, where DMC is a titanium alloy (VT1-00 or VT-9) or niobium (Nb1). The most promising methods for the upsetting of the billets after compacting by hot isostatic pressing have been chosen, and a pilot technology for the production of high-quality defectless 11-layer 3-mm-thick sheets using hot rolling to a total reduction of approx 90 percent has been developed. Structural studies of the sheets indicate that the most promising materials for the DMC are a high-strength VT-9 alloy and, especially, high-melting-temperature niobium (Nb1). The strain resistance of Nb1 is comparable with that of a gamma-TiAl-based superlight alloy, and diffusion processes between the layers of the related composite material are significantly slower than those in the layered composite materials with a DMC made of VT-9 and, especially, VT1-00.