Abstract
Re-evaluation of existing alloy systems is shown to have taken place concurrently with a decline in the development of new wrought superalloys. As a result of the various factors that determine the nature of the mechanical properties the concept of controlling the microstructure to improve specific properties has been introduced. The effects of thermomechanical processing on structural and mechanical properties are reviewed using examples selected from Waspaloy, 901; A-286, 718, and Astroloy. A review is made of the influence of grain size, grain-boundary conditions, and matrix structure on selected properties, including low-cycle fatigue, rupture ductility, tensile characteristics, and notch sensitivity. Isothermal forging and hot isostatic pressing are briefly mentioned, and some speculations made on future developments.
Get full access to this article
View all access options for this article.