Effect of (Pr + Ce) addition and T6 heat treatment on microhardness and corrosion of AlSi5Cu1Mg alloy

Abstract

The effects of T6 heat treatment and 0.6 wt% (Pr+Ce) addition on microstructure, microhardness, and corrosion of AlSi5Cu1Mg alloy were investigated. Optical microscopy and scanning electron microscopy revealed that the T6 heat treatment and the addition of 0.6 wt% (Pr+Ce) effectively refined the α-Al and eutectic Si phases, which were uniformly distributed with Al 2 Cu phase in the alloy. Microhardness, weight loss, hydrogen evolution, Tafel polarization, and EIS tests showed that the combination of T6 heat treatment and 0.6 wt% (Pr+Ce) addition resulted in the best corrosion resistance and microhardness of the alloy. The microhardness of the AlSi5Cu1Mg+0.6 wt% (Pr+Ce)/T6 (115 HV) was 27.8% higher than that of the matrix (90 HV). At the same time, the corrosion current density of the alloy also reached the minimum value (38.4 μA cm −2 ). The T6 heat treatment and the addition of (Pr+Ce) can significantly decrease the average grain size, change the redistribution of the precipitated Al 2 Cu phase, refine the Si phase, and increase the pitting formation position, thus reducing the sensitivity of exfoliation corrosion.

Microstructure, microhardness and corrosion resistance of laser cladding Al2O3@Ni composite coating on 304 stainless steel

“…The Tafel polarization curves analyses the corrosion mechanism of the alloy surface by the polarization reaction of the anode part and the cathode part [41]. The Tafel polarization curves of 304 stainless steel and Al 2 O 3 @Ni composite coating in HCl solution are shown in Fig.…”