High strain rate dynamic behaviour of AlSi12 alloy processed by selective laser melting

Selective laser melting (SLM) is a layer-by-layer metal additive manufacturing process. The parts produced using SLM may be subjected to severe dynamic loading conditions during service. Very little published research exists in understanding the response of 3D printed metal parts subjected to high strain rate loading. The present work is focused on studying the behaviour of SLM processed AlSi12 aluminium alloy parts under quasi-static and high strain rate dynamic compression for specimens built at different orientations and locations. The dynamic compression is carried out at room temperature as well as at an elevated temperature on the split Hopkinson pressure bar at strain rates of 670-840/s and the quasi-static test is conducted at a strain rate of 4 x 10(-3)/s. The effects of build orientations, strain rate and temperature on mechanical behaviour of AlSi12 specimens are investigated. Also, the microstructure and micro-hardness of the dynamically tested AlSi12 specimens are analysed. Results show that increased temperature in dynamic loading significantly reduces the yield strength and ultimate compressive strength of 3D printed AlSi12 specimens. Flow stress remains almost constant under quasi-static and dynamic loading at room temperature, while it increases with strain rate at high temperature. Build orientation also affects the micro-hardness and yield stress of quasi-statically tested parts with vertical orientation providing maximum values.