Title:	Upward unsteady-state solidification of silute Al–Nb alloys : microstructure characterization, microhardness, dynamic modulus of elasticity, damping, and XRD analyses
Authors:	Coutinho, Maycol Moreira Silva, José Ildon Saraiva Sousa, Thiago Primo Rosa, Daniel Monteiro
Assunto::	Ligas de aluminio e nióbio Microestrutura Solidificação
Publisher:	MDPI
Citation:	COUTINHO, Maycol Moreira et al. Upward unsteady-state solidification of silute Al–Nb alloys: microstructure characterization, microhardness, dynamic modulus of elasticity, damping, and XRD analyses. Metals, v. 9, n. 6, 713, 2019. DOI: https://doi.org/10.3390/met9060713. Disponível em: https://www.mdpi.com/2075-4701/9/6/713. Acesso em: 28 jun. 2019.
Abstract:	Aluminium alloys form many important structural components, and the addition of alloying elements contributes to the improvement of properties and characteristics. The objective of this work is to study the influence of thermal variables on the microstructure, present phases, microhardness, dynamic modulus of elasticity, and damping frequency in unidirectional solidification experiments, which were performed in situ during the manufacturing of Al–0.8 Nb and Al–1.2 Nb (wt.%) alloys. Experimental laws for the primary ( 1) and secondary ( 2) dendritic spacings for each alloy were given as a function of thermal variables. For Al–0.8%wt Nb, 1 = 600.1(˙T)􀀀1.85 and 2 = 186.1(VL)􀀀3.62; and for Al–1.2%wt Nb, 1 = 133.6(˙T)􀀀1.85 and 2 = 55.6(VL)􀀀3.62. Moreover, experimental growth laws that correlate the dendritic spacings are proposed. An increase in dendritic spacing influences the solidification kinetics observed, indicating that metal/mold interface distance or an increase in Nb content lowers the liquidus isotherm velocity (VL) and the cooling rate (˙T). There is also a small increase in the microhardness, dynamic modulus of elasticity, and damping frequency in relation to the composition of the alloy and the microstructure.
Licença::	© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
DOI:	https://doi.org/10.3390/met9060713
Appears in Collections:	Artigos publicados em periódicos e afins

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