The effect of aluminum and tantalum concentrations on a refractory metal complex concentrated alloy is reported, particularly with respect to their effect on microstructure and phase composition of the alloy in cast and annealed form. Alloys with an equiatomic composition, (AlCrMoTaTi), an aluminum‐lean composition (Al0.75CrMoTaTi), and a tantalum‐lean composition (AlCrMoTa0.75Ti) are produced via arc melting. The alloys exhibit multiphase structures, confirmed by X‐ray diffraction, microstructural characterization, and thermal analysis. The minor off‐equiatomic adjustments of aluminum and tantalum in this alloy system did not drastically alter the prevalence of the Cr–Ta‐based Laves phase. Correlations between thermodynamic predictions and observed phase transformations via thermal analysis are improved upon refinement of calculations removing impractical intermediate phases. Experimental findings provide information for the refinement of thermodynamic modeling and deliver additional insight into the optimization of alloy compositions within this five‐component system.
Herein, the development of refractory complex concentrated alloys in the Al–Cr–Mo–Ta–Ti alloy system is reported. Alloys with modified Al and Ta concentrations are designed using CALPHAD tools and produced via arc melting and characterized in both as‐cast and annealed forms. Properties of the alloys, nature of the microstructures, and phase transformation behavior are described via X‐ray diffraction, microstructural characterization, microhardness, and differential scanning calorimetry. Two alloys, namely, Al0.25CrMoTa0.8Ti and Al0.75CrMoTa0.8Ti, are represented by a body‐centered‐cubic matrix phase after annealing, along with a secondary Cr–Ta Laves phase of the C15 and C14 polytypes, respectively. In as‐cast and annealed forms, the Al0.75CrMoTa0.45Ti alloy comprises a single‐bcc phase. Microhardness of the Laves phase containing alloys demonstrates susceptibility to cracking, whereas the Al0.75CrMoTa0.45Ti alloy displays high specific hardness, signs of ductility as evidenced by slip traces near indentations, and minimal scatter of hardness values.
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