Simultaneous XEDS‐EBSD Study of NiCoAlFeCu(Cr,Ti) Multi‐Component Alloys

• Published in: Advanced engineering materials Vol. 20; no. 4
• Main Authors: Cruz‐Gandarilla, Francisco, Coreño‐Alonso, Oscar, Cabañas–Moreno, José Gerardo, Chan, Lisa H., Gómez‐Esparza, Cynthia, Martínez Sánchez, Roberto
• Format: Journal Article
• Language: English
• Published: 01.04.2018
• Subjects: EBSD; high‐entropy alloys; mechanical alloying; NiCoAlFeCuCrTi alloys; XEDS; X‐Ray diffraction
• ISSN: 1438-1656; 1527-2648
• DOI: 10.1002/adem.201700215

NiCoAlFeCu, NiCoAlFeCuCr, and NiCoAlFeCuCrTi high‐entropy alloys are prepared by mechanical alloying and sintered at 1200 °C and a pressure of 1.5 GPa for 3 h. The alloys were characterized by X‐ray diffraction (XRD), electron backscatter diffraction (EBSD), and X‐ray energy dispersive spectrometry (XEDS). The phases found are mostly variants of the face centered cubic (fcc) phases (space group Fm3¯m), bcc (space group Im3¯m), and hexagonal (space group P63/mmc). Adding Ti to the NiCoAlFeCuCr system has strong effects on the solubility of the elements in the different phases and increases dramatically the number of phases present. The use of EBSD and XEDS allowed identification of a cubic phase in NiCoAlFeCu samples, which cannot be identified by XRD alone, and confirmed its identification by XRD in NiCoAlFeCuCr samples. The spatial distribution of phases and the grain structure in the three different samples, measured by EBSD and XEDS, is reported. Phase analysis in NiCoAlFeCu HEA alloys by XRD is frequently complicated by the simultaneous occurrence of several simple fcc and bcc structures. By linking together EBSD and XEDS analysis, cubic phases with similar lattice parameters are differentiated and their microscopic spatial distribution is revealed.