Evaluation of and Fracture Behavior of Alloy 90 Sheets

Abstract

ALLOY–90 refers to a family of austenitic nickel-based super alloys. Nimonic alloys typically consist of roughly 80% nickel and 20% chromium with additives such as titanium and aluminium. Nickel-based superalloys, among several high temperature structural alloys, are the prime materials for numerous advanced high temperature structural components. Several advanced processing technologies, such as isothermal forging, equiangle extrusion, investment casting, directional solidification and single crystal technologies, similar and dissimilar metal joining, destructive and nondestructive testing too have also evolved. In the past, a few attempts have been made to study the deformation behavior and Fracture behavior of the alloy 90 sheets for sheet metal applications. However, these studies were limited to different commercial grades such as cold rolled sheets of thicknesses upto 2 mm. None of these studies have addressed the influence of microstructure and texture for ultra-thin sheet applications. Hence, a comprehensive study has been undertaken to evaluate the ambient temperature deformation characteristics as a function of degree of cold rolling and ageing. In order to determine the tensile properties, tensile tests are conducted on the alloy-90 sheets of 1 mm and 0.5 mm thicknesses in different heat treat conditions in different specimen orientations namely R, R+30o, R+45o, R+60o and RT. The fracture behavior of the alloy sheets are studied to determine the mode of fracture. present work includes comparison of tensile properties of macro and micro specimens of alloy 90 sheet and properties evaluated in the present work include tensile flow behavior in various microstructural conditions such as Cold rolled, Solution treated, aged for different times.