O. Covarrubias, E. Osvaldo, Frisa Aerospace SA de CV, Santa Catarina, Mexico
Industrial applications of alloy 909 can include components made from seamless rings produced by forging/rolling procedures. Manufacturing conditions will affect microstructure and mechanical properties of metallic alloys, including alloy 909: forging/rolling procedures determine grain size, meanwhile heat treatment can promote or inhibit presence of intergranular and transgranular phases. Combination of processes, forging and heat treatment will have a direct effect on microstructure, affecting mechanical properties. Several forgings, made from 909 alloy, were produced considering industrial conditions. Samples from these rings were extracted and exposed to different heat treatments. Stress-rupture testing was performed, and microstructures from these samples were evaluated. Correlation between microstructures and stress-rupture properties is evaluated to determine which conditions promote better stress-rupture behavior for alloy 909.
Summary: The alloy 909 (UNS N19909) is a Ni-Fe-Co alloy used for jet-engines components manufacture due to its low thermal expansion properties and high-strength at elevated temperatures. An important test to predict alloy behavior at operation conditions is stress-rupture testing; this property can be affected by microstructural properties promoted by parameters like forging conditions and heat treatment procedures. Several rings were produced considering selected forging and heat-treatment conditions. Samples from these rings were then exposed to stress-rupture testing. Microstructures of these samples were evaluated by optical and electronic microscopy to determine relationships between microstructure and stress-rupture properties.
