In-situ heated stage scanning electron microscope analysis and characterisation of recrystallization behaviour of a 7000 series alloy with nickel additions

Observation of microstructural evolution and processes are typically observed by means of “snap shots” where a sample is removed from a thermal cycle and then analysed using varying microscopy techniques. Advanced techniques such as hot stage electron back scattered diffraction (EBSD) and fore scattered detection (FSD) allow for direct in-situ observation of these processes to give better and more accurate analysis. This paper investigates two 7000 series alloys with a 1.6 wt% nickel addition and compares the recrystallization behaviours of both. Recrystallization was observed to occur at a higher rate and at a lower initiation temperature of 277 °C in sheet rolled from the original smaller 10 kg cast of material compared to the higher temperature of 285 °C in sheet from a second larger 60 kg cast. In-situ back scattered scans of both alloys microstructures were observed to be near identical to bulk back scattered scans taken from samples recrystallized externally, validating the accuracy of the observed results.