Abstract text (incl. figure legends and references)

High temperature alloys have been remarkably known for their good mechanical behaviors at elevated temperature. Nickel-based and cobalt-based superalloys alongside with their minor alterations by adding small amount of transition elements are commercially known for their exceptional high-temperature strength, outstanding resistance to oxidizing environments up to 1150°C, premier resistance to nitriding environments, and excellent long-term thermal stability. However, the production cost effectiveness, specific strength, and high alloy homogeneity have been the major drawbacks of these superalloys. Quinary alloys with five equiatomic elemental composition have been emerged with promising properties. They can be prepared through different routes. The different processing schemes create distinct microstructures and most likely suitable for different applications. In this study, the equiatomic AlCrFeNiCu alloy was prepared by arc melting method with the expensed graphite electrodes. The fifty-gram as cast ingots were homogenized at 1,200°C with various times. To verify the stability at elevated temperature, tempering at 700°C for 2 hours was subsequently performed. Microstructures were investigated under scanning electron microscope (Zeiss, Auriga) equipped with energy dispersive spectroscopy. Phase identification was performed using X-ray diffraction (Bruker, D8). The local geometric of Fe and Ni were studied using X-ray absorption spectroscopy at SUT-NANOTEC-SLRI XAS beamline (BL5.2) facilitated by Synchrotron Light Research Institute (Nakhon Ratchasima, Thailand). The alloys were dendritically solidified. Microstructural observation suggested that the dendritic region composed of Fe-Cr and Ni-rich lamellar structures. The interdendritic regions consisted of Cu-rich phase containing nanosized precipitates alongside intermetallic compound. The modulated microstructure in dendritic regions enhanced mechanical properties. Even at high temperature tempering, the microhardness had not been sacrificed. Moreover, the phase transformation detected by X-ray diffraction measurements showed that nanoprecipitates and morphological changes occurred during heat treatments. X-ray absorption near edge spectroscopy (XANES) and extended x-ray absorption fine structure (EXAFS) spectroscopy were used to determine the local structures of Fe and Ni atoms in the alloy lattice. The spectra confirmed the formation of disordered BCC structure.