Evaluation of ingots and alpha-extrusions of gamma alloys based on Ti–45Al–6Nb

Three gamma TiAl alloys having compositions within the range of Ti–45Al–6Nb–0.4C–0.2Si–xB–yCr–z(W+Hf) were produced into 6.3 cm diameter ingots by the ingot-skull melting (ISM) technique. Billets from the ingots were hot-worked by the so-called ‘alpha extrusion» process that yields in situ lamellar structures. Isothermal aging experiments at 900 and 1000 °C were conducted on the extruded material to investigate the microstructural stability and...