Abstract
Mechanical and electrical properties of an Al-Er-Zr alloy were investigated. Microhardness and resistometry measurements were supplemented by transmission electron microscopy and scanning electron microscopy.
Resistivity decreases during isochronal annealing take place within the following temperature intervals: 150-270 °C, 300-420 °C and 450-570 °C. The isochronal microhardness curve reflects hardening effects at corresponding temperatures.
However, no thermal effect was observed in the DSC curves ranging from 25 °C to 600 °C. A transmission electron microscopy observation of the alloy studied isochronally annealed up to 390° C revealed a high density of L12-structured particles, some of which had nucleated on dislocations.
The distinct electrical resistivity, as well as microhardness, changes are in all cases connected with the precipitation and evolution of the Al3Er, Al3Zr and/or Al3(Er,Zr) particles.