The Cu/Nb Ratio Influencing Microstructure, Mechanical and Electrical Properties in As-cast Al-3Cu-xNb Alloys

Abstract

In this work, solidi cation experiments were performed with Al-3CuxNb alloys (x = 0.5, 3 and 5wt.%). The role of the Cu/Nb ratio was investigated on thermal parameters such as growth and cooling rates (V L and T R ), structure, microhardness (HV) and electrical properties such as electrical resistance, resistivity and conductivity (R, ρ, and σ, respectively). A columnar to equiaxed grain transition (CET) was observed for lower Cu/Nb ratios. The typical solidi cation microstructure was quanti ed by means of secondary dendritic spacings (λ 2 ). It was observed that the decrease of the Cu/Nb ratio with the increase of the Nb content increased the HV, R, and ρ values, but the σ values decreased. It was deduced that the harder particles of the Al 3 Nb and Al 2 Cu intermetallic phases contributed to the increase of HV, while the Al 3 Nb phase in uenced the decrease of electrical conductivity with the increase of Nb content.

Efeitos dos parâmetros térmicos e da concentração de níquel na dureza de ligas Al-Cu-Ni solidificadas unidirecionalmente

“…A ascendente demanda da indústria moderna por materiais com propriedades cada vez mais elevadas e específicas exige um conhecimento mais aprofundado do processo de solidificação de metais. As ligas de alumínio fornecem boas propriedades elétricas, mecânicas, físicas, químicas etc (BARROS et al, 2024;MENDES et al, 2023;MIRAMONTES et al, 2022). Nesse contexto, o alumínio, por apresentar um baixo peso específico e poder combinar-se com a maioria dos metais de engenharia, é capaz de agregar características tecnológicas ajustadas de acordo com a aplicação do produto a ser fabricado.…”