Relatively new wrought g’ strengthened age-hardenable nickel superalloy HAYNES®282, designed by Haynes International (USA) for improved high temperature properties, has a unique combination of creep strength, thermal stability, weldability, and fabricability not found in currently available commercial alloys. Due to a good oxidation resistance this alloy could potentially be used in high-performance, high-temperature environments, e.g. as an attractive candidate material for high temperature/high pressure boiler and turbine components in Advanced Ultrasupercritical Power Plants (A-USC).
This research is focused on the applicability for use of commercial wrought HAYNES®282 in casting applications, particularly as a possible candidate alloy for A-USC large-scale turbine components for next generation power plants. Therefore, information on high temperature interaction between liquid HAYNES®282 alloy and diferent oxides is of practical importance for proper selection of refractory materials to be used for its melting and casting in order to produce defect-free castings.
This paper presents the results of high temperature investigation of wetting behavior and interface formation during interaction between liquid HAYNES282 alloy and selected oxides commonly used for industrial production of foundry appliances (crucibles, moulds, filters, etc.) such as Al2O3, MgO, Y2O3, ZrO2 (ZrO2 stabilized with either MgO or Y2O3).
The tests were done by a sessile drop method at a temperature of 1500°C under protective atmosphere. Specially developed procedures for high-temperature sessile drop wettability tests combined with in situ opening of the metal/ceramic interfaces at the testing temperature by either pushing or sucking an alloy drop as well as by tilting an oxide substrate were used. The molten alloy behavior during high-temperature testing was continuously imaged and recorded by super fast CCD camera.
Detailed structural characterization of interfaces was done on the solidified metal/ceramic couples by means of SEM+EDS analysis coupled with scanning probe microscopy analysis. Special attention has been paid to examination of in situ opened area of the substrate being in contact with the molten droplet of HAYNES282 alloy during high-temperature testing.
The results of wettability tests are discussed in terms of chemical interactions in relation to the role of alloying elements on the interface formation in selected HAYNES 282/oxide systems.