Article ID Journal Published Year Pages File Type
5460804 Journal of Alloys and Compounds 2017 31 Pages PDF
Abstract
The present paper investigates the potential of the SPS route to improve the mechanical properties of the AZ91 alloy by controlling, in-situ within the SPS machine, the precipitation kinetics of the hardening Al12Mg17 precipitates. To this end, an as-atomised AZ91 powder was sintered by SPS and the formation of the Al12Mg17 phase was controlled by introducing an in-situ precipitation treatment at 200 °C in the wake of a conventional sintering treatment cycle at 360 °C. The influence of the sintering and the in-situ precipitation dwell times on the microstructure (grain size, Al12Mg17 vol fraction) and associated mechanical properties (hardness, compressive properties) were investigated. Using longer sintering times at 360 °C improved the material cohesion while keeping fairly fine grain sizes. The subsequent treatment at 200 °C triggered continuous and discontinuous Al12Mg17 precipitations. Compared to the cast AZ91-T6 treated alloy, the SPS material produced by a combination of 2 h of sintering followed by 2 h of in-situ precipitation led to a significant improvement in mechanical properties: hardness +16%, Yield Compressive Strength (YCS) +59%, Ultimate Compressive Strength (UCS) +32% and strain at UCS +12%.
Related Topics
Physical Sciences and Engineering Materials Science Metals and Alloys
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