Effect of cooling rate and composition on the microstructure and mechanical properties of (Ni0.92Zr0.08)100−xAlx (0 ≤ x ≤ 4 at.%) ultrafine eutectic composites

Abstract

Abstract

Microstructural Refinement for the Reduction of Casting Thickness in Ni-Zr-(Al) Eutectic Composites and Evaluation of the Cooling Rates

“…The field emission scanning electron microscope of FESEM-SUPRA 40, Carl-Zeiss SMT AG (Germany) was used for microstructural characterization to measure the nanometer size lamellae thickness. The secondary dendritic arm spacing (SDAS) and the interlamellar spacing (λ) were estimated for evaluation of solidification parameters [10]. The SDAS has been estimated from the formula SDAS = L/(N-1), where the primary dendrite arm (L) length and the number of the secondary arms (N) in the longitudinal section, was measured at the centre of the rods and ingots.…”

“…However, the rapid solidification in the cast rods may derive many other microstructural features which are yet to be explored. On the other hand, due to very high cooling rate, non-equilibrium composition is expected to evolve in as-cast rods [2,9,10].Therefore, in the present work, the microstructural features have been quantified and are used as parameters to correlate the solidification parameters such as cooling rate, segregation, and homogeneity in the cast rods of diameters 2 mm, 3 mm, and 5 mm and the results are reported.…”

“…Nano-/ultrafine eutectic composites have been developed in several multicomponent Ti-, Fe-, Ni-, Zr-systems with superior mechanical, corrosion and creep resistance properties [7][8][9][10]. Recently, low melting temperatureNi-Zr-(Al) ultrafineeutectic alloys, having high strength and large room temperature plasticity, are being developed as an advanced Ni-base alloy [8][9][10].…”

“…Nano-/ultrafine eutectic composites have been developed in several multicomponent Ti-, Fe-, Ni-, Zr-systems with superior mechanical, corrosion and creep resistance properties [7][8][9][10]. Recently, low melting temperatureNi-Zr-(Al) ultrafineeutectic alloys, having high strength and large room temperature plasticity, are being developed as an advanced Ni-base alloy [8][9][10]. These alloys are comprised of γ-Ni dendritic phase homogeneously embedded on a eutectic matrix of γ-Ni and Ni5Zr lamellae [8,10].The Al addition increases the volume % of γ-Ni dendrites [9,10].…”

“…Recently, low melting temperatureNi-Zr-(Al) ultrafineeutectic alloys, having high strength and large room temperature plasticity, are being developed as an advanced Ni-base alloy [8][9][10]. These alloys are comprised of γ-Ni dendritic phase homogeneously embedded on a eutectic matrix of γ-Ni and Ni5Zr lamellae [8,10].The Al addition increases the volume % of γ-Ni dendrites [9,10]. However, the rapid solidification in the cast rods may derive many other microstructural features which are yet to be explored.…”