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Structural aeroengine components like forged high-pressure compressor discs are usually made of nickel-based superalloys due to their excellent high-temperature properties. [1] Especially Inconel 718 (IN718) is very widespread because of its excellent strength at elevated temperatures in combination with good fatigue and creep properties. [2] The specific performance of IN718 can mostly be attributed to the fine, semi-coherent c² precipitates, which act as a strengthening phase within the nickel matrix. c² is formed during a twostep aging sequence [3] which is performed after forging and before machining to final geometry. As dislocations represent potential nucleation sites for c² precipitates, rapid quenching to freeze dislocations increases the number of precipitates formed during the annealing cycle and, therefore, lead to a higher final strength. This optional heat treatment route which involves water quenching from the forging temperature, instead of solution annealing and subsequent air cooling, is referred to as ªdirect agingº. [4] However, water quenching leads to high residual stresses within the components. Although quenching is followed by the final aging treatment (with subsequent air cooling), residual stresses are not completely relieved. Therefore, heavy distortions of the forged component during machining to its final shape are still observed. These can lead to non-correctable deviations from COMMUNICATIONS

Knowledge of the evolution of residual stresses developing during fabrication of industrial components is steadily gaining importance. Therefore, the prevailing residual stresses in a number of identical hot-forged water quenched compressor discs made of nickel-base alloy IN718 have been studied by neutron diffraction. Simultaneously, independent finite element simulations (FEM) have been performed characterizing different quenching rates. Furthermore, temperature measurements have been performed during water quenching and the simulated temperatures are compared to the measured ones. The results of the finite element simulations agrees well with those obtained from neutron diffraction and temperature measurements.

Cost reduction and weight saving are most important principles governing design and construction of aircrafts. Advanced alloys and thermo‐mechanical treatments as well as new and optimized production processes are being developed. For example, welding of fuselage components like stringers or clips made of Al alloys can have several advantages over riveting. Retention of optimum weld microstructure and properties as well as control of welding related residual stresses and distortion is essential. In the context of risk analysis and damage tolerance it will be of growing importance to study residual stress fields in weld configurations and their influence on fatigue crack propagation. In this paper, methods to evaluate residual stresses in turbine discs and laser welded Al joints are reviewed.