Unravelling the combined effect of cooling rate and microalloying on the microstructure and tribological performance of Cu50Zr50

The combined effect of the cooling rate and microalloying has been studied from suction casted Cu50Zr50, Cu49.5Zr50Fe0.5 and Cu49Zr50Fe1 at. % rods of 2 mm and 4 mm diameter. For the 2 mm samples, -1000 K/s cooling rate, the microstructure mostly consists of B2 CuZr austenite and it is basically the same for all compositions. However, 0.5 at. % Fe addition promotes the formation of stress-induced B19' martensite upon wear testing thus improving the wear resistance of the alloy. For the 4 mm samples, -250 K/s cooling rate, a multiphase intermetallic is predominant and when microalloyed with 0.5 at. % Fe, a relatively large volume fraction of as-cast B33 CuZr martensite is formed thus resulting in a reduction of the wear resistance. At high cooling rate the wear mechanism is predominantly delamination wear while for low cooling rate the large continuous grooves are indicative of abrasive wear.

Automated summary

The combined effect of cooling rate and microalloying on Cu-Zr alloy has been studied. A higher cooling rate promotes the formation of B2 CuZr austenite, while the addition of 0.5 at. % Fe promotes the formation of B19' martensite, resulting in improved wear resistance for 2 mm samples. For 4 mm samples, a lower cooling rate leads to the formation of multiphase intermetallic, and microalloying with 0.5 at. % Fe results in a relatively large volume fraction of B33 CuZr martensite, leading to reduced wear resistance.