Optimizing microstructure and performance: The impact of pre-deformation and rotational speed on friction stir processed Cu-W composites

Abstract

This study investigated the effects of pre-deformation induced by asymmetric rolling on copper-based metal, as well as rotational speed during friction stir processing, on the microstructure, mechanical properties, and electrical conductivity of tungsten-reinforced copper matrix composites. The results show that increasing the rotational speed up to 800 rpm leads to a more uniform distribution of tungsten particles within the stir zone. However, at rotational speeds above 800 rpm, the distribution of tungsten reinforcing particles becomes less uniform. The accumulated strain in the stir zone increases from 0.3056 to 0.3967 s^-1 as the rotational speed rises from 600 to 1200 rpm. Additionally, as the tool rotational speed increases from 600 to 1200 rpm, the grain size in the stir zone grows from 6.2 ± 0.7 to 13.2 ± 1.5 µm. The Cu-W composite processed at a tool rotational speed of 800 rpm achieves the highest values in hardness (124.9 ± 8.9 HV0.1), ultimate tensile strength (307.4 ± 11.8 MPa), tensile toughness (92.1 ± 1.1 MJ/m³), and electrical conductivity (92.8 ± 1.3 %IACS). Compared to the as-rolled copper-based metal, the electrical conductivity of the Cu-W composite fabricated at 800 rpm increases by 8.8 %.