Microstructure Evolution and Composition Control during the Processing of Thin-gage Metallic Foil (Preprint)

摘要

The manufacture of thin-gage superalloy and gamma-titanium-aluminide foil products via near-conventional thermomechanical processing (TMP) and two different vapor-deposition methods was investigated. TMP was based on hot-pack rolling of plate and sheet. Foils of the superalloy LSHR and the near-gamma titanium aluminide Ti-45.5Al-2Cr-2Nb made by this approach exhibited excellent gage control and fine two-phase microstructures. The vapor-phase techniques utilized magnetron sputtering (MS) of a target of the desired product composition or electron-beam physical vapor deposition (EBPVD) of separate targets of the specific alloying elements. Thin deposits of LSHR and Ti-48Al- 2Cr-2Nb made by MS showed uniform thickness/composition and an ultrafine microstructure. However, systematic deviations from the specific target composition were found. During subsequent heat treatment, the microstructure of the MS samples showed various degrees of grain growth and coarsening. Foils of Ti-43Al and Ti- 51Al-1V fabricated by EBPVD were fully dense.