High Temperature Wear Behavior of AlMgScZr Alloy Produced By Laser Powder Bed Fusion

The present study is focused on the wear behavior of an innovative AlMgScZr alloy manufactured using the laser powder bed fusion process. This material, commercially known as Scalmalloy®, exhibits high strength and ductility, together with low anisotropy, which instead represents a strong limitation for other alloys produced by additive manufacturing processes. The typical heat treatment for this alloy is an annealing treatment at 325 °C, which leads to a further increase in mechanical performances as a result of precipitation of intermetallic particles containing Sc and Zr. These precipitates usually exhibit good thermal stability, as shown by studies of alloys with similar chemical composition but manufactured via conventional processes. This ensures good performance of the alloy also at high temperatures, in the range 100-250 °C. Among the mechanical properties of this innovative alloy, wear resistance has rarely been studied so far, especially as a function of temperature. However, its evaluation can provide valid ideas for new applications, not only in the aerospace industry, but also in the automotive field. For this reason, the wear behavior of AlMgScZr alloy at high temperatures has been studied in this work. Pin-on-disk tests were performed at different temperatures on samples produced by additive manufacturing followed by annealing at 325 °C for 4 h. The coefficient of friction was monitored during the tests and the wear rate was calculated from the measurement of the track profile. Furthermore, the damaging mechanisms were accurately studied by observations of the morphology of the sample surface after progressive testing. These analyses, performed by using a scanning electron microscope, allowed the identification of the evolution of the wear mechanism with temperature. These results can be used for the determination of optimum ranges for application of this alloy for components that can experience high temperature exposure during their service.