Effect of Ce on castability, mechanical properties and electric conductivity of commercial purity aluminum

摘要

Effects of Ce addition on microstructure, castability (lfuidity and hot tearing sensitivity), mechanical properties and electric conductivity of commercial purity aluminum (CP-Al) were investigated through microstructure observation and performance tests. Results show that adding Ce in a CP-Al can considerably reifne the grains, and has an important inlfuence on the amount, crystallographic forms, and distribution of secondary phases. Addition of Ce also has a large impact on the lfuidity and hot tearing sensitivity (HTS) of the CP-Al. With the addition of Ce from 0.1wt.%to 0.5wt.%, the lfuidity of CP-Al is ifrst increased remarkably and then decreased, and the HTS has an opposite response. The best castability of the studied alloys appears to be at 0.2wt.%-0.3wt.%Ce addition. The remarkable improvement in castability is attributed to the considerable reifnement of grain structure. Ce addition can also lead to a signiifcant rise in electric conductivity. The maximum conductivity of the as-cast CP-Al is 59.7% IACS with an addition of 0.2wt.%Ce. The T7 heat treatment can further improves the conductivity to 60.7% IACS. The Ce-induced evolution of the secondary phases is believed to be the mechanism for it.