저널

Cavitation erosion properties of the Cu-9Al-4.5Ni-4.5Fe alloys (Al-bronze) surface-modified by flame quenching process have been investigated. After flame quenching at above $T_{eta}$, the surfaces of Al-bronze with $alpha$ + $ extsc{k}$ structure have been changed into the $alpha$ + $eta$` martensite phases by the eutectoid reaction of $alpha$ + $ extsc{k}$longrightarrow$eta$ followed by the martensite transformation of $eta$longrightarrow$eta$`. As a result of cavitation test, the measured incubation time and erosion rate of the $alpha$ + $eta$` alloy was 1.2 times higher and 1.5 times lower, respectively, compared to those of the conventional $alpha$ + $ extsc{k}$ alloys, showing a remarkable increase of cavitation resistance with the formation of $eta$` martensite. This is attributed to a preferential erosion of the $ extsc{k}$ precipitates that show the lowest resistance among the $alpha$, $ extsc{k}$, $eta$` phases under cavitation loading.ases under cavitation loading.

Cavitation;Al-bronze;Pump impeller;Erosion;Flame quenching;Surface treatment;Martensite;