Abstract: The alloy is based on doped iron aluminide Fe.sub.3 Al. It contains the following alloying constituents in atomic percent:______________________________________ 24 28 aluminum, 0.1 2 niobium, tantalum and/or tungsten, 0.1 10 chromium, 0.1 2 silicon, 0.1 5 boron, 0.01 2 titanium, ______________________________________the remainder being iron. The alloy is notable for a high oxidation resistance and corrosion resistance even at temperatures above 700.degree. C. and is preferably used in components which are exposed to oxidizing and corrosive actions at high temperatures and low mechanical stress.

Abstract: Process for the production of longitudinally-directed coarse-grained columnar crystals in an oxide-dispersion-hardened nickel-based superalloy which is difficult to recrystallize, starting from a warm-kneaded fine-grained structural status, by heating to a preheating temperature T.sub.pre, which is below the minimum recrystallization temperature T.sub.rec min necessary for the material and is at least at the solution annealing temperature of the carbides in the .gamma.-matrix, keeping at T.sub.pre for 5 min to 6 h, for the purpose of isothermal annealing, and immediately heating to recrystallization temperature T.sub.rec at 10.degree. to 40.degree. C./min without prior cooling, and cooling to room temperature.

Abstract: Process for increasing the room-temperature ductility of a workpiece composed of oxide-dispersion-hardened nickel-base superalloy and existing as coarse, longitudinally oriented columnar crystallites by subjecting the previously zone-annealed workpiece to a solution anneal in the temperature range between 1,160.degree. and 1,280.degree. C. under argon atmosphere for 1/2 h to 5 h and then to a purposefully chosen cooling down at a rate of 0.1.degree. C./min to 5.degree. C./min to a temperature of 500.degree. to 700.degree. C. Thereafter the workpiece is cooled down to room temperature in air. Preferred purposefully chosen cooling down rate: approx. 0.5.degree. C./min.

Abstract: Two component workpieces (1, 3) consisting of different superalloys or of the same superalloy are bonded together to form a monolithic whole, with the insertion of a layer 1-2 mm thick consisting of a powder (4) of composition similar to or identical to that of the component workpieces (1, 3), by hot pressing in accordance with the diffusion bonding process. The workpiece surfaces to be bonded do not have to have narrow tolerances, but are with advantage provided with grooves (5). The groove depth (s) may be 0.25 mm. Pressing temperature =950.degree.-1,000.degree. C., deformation velocity .epsilon.=1-5.10.sup.-1 s.sup.-1, degree of deformation .epsilon.=0.1-0.02. The process is suitable for the bonding together of component workpieces (1) consisting of a dispersion-hardened, nickel-based superalloy or of component workpieces (1) of such an alloy and workpieces (3) consisting of a cast conventional superalloy.

Abstract: A fine-grained workpiece having improved mechanical properties is produced from a nickel-based superalloy by two-part forging, a blank being converted, in a first isothermal hot-forming step (curve b) above the solution-annealing temperature for the .gamma.'-phase (line a), into an intermediate form and the latter then being finally forged to give the end form in a second isothermal hot-forming step (curve c) just below the solution-annealing temperature for the .gamma.'-phase. For the first step, a degree of deformation .epsilon. of of at least 0.7 at a mean deformation rate .epsilon. of about 10.times.10.sup.-3 s.sup.-1 is required here. The second step is carried out at deformation rates .epsilon. which are one to two powers of 10 lower than those of the first step.