Effect of T6 heat treatment on microstructural evolution, carbon nanotube dispersion, defect formation, and mechanical properties of Al-Cu nanocomposites
Year: 2026
Type: article
Abstract: ABSTRACT Material processing routes directly influence microstructure and, consequently, mechanical proper-ties. In this context, the incorporation of carbon nanotubes (CNTs) into metallic matrices has emerged as a promising strategy for improving performance. This study aimed to process and char-acterize Al-Cu/CNT nanocomposites and compare them with the base Al–Cu alloy. Samples were produced by casting, with the addition of multi-walled CNTs during the semi-solid stage. The re-sults indicated that CNTs act as heterogeneous nucleation sites, promoting significant grain refine-ment. As the CNT content increased, a reduction in grain size and an increase in grain density were observed, contributing to improvements in mechanical strength of approximately 15% in the as-cast condition and up to 35% after T6 heat treatment. Despite the presence of porosity and micro-structural heterogeneities, hardness increased in all composites, mainly associated with the precipi-tation of Al2Cu intermetallic phases. Scanning electron microscopy revealed CNTs located near defects, suggesting their involvement in defect formation mechanisms. Raman spectroscopy showed modifications in the D and G band intensity ratio for incorporated CNTs, indicating structural changes due to mechanical stresses, without clear evidence of degradation. Overall, reinforcement efficiency depends strongly on dispersion quality and interfacial bonding.
Source: Matéria (Rio de Janeiro)
Institution: Universidade Federal do Pará
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7220464682