Dynamic recrystallization, dislocations and twins occur during
extrusion which enhance the mechanical properties. Extrusion
is able to eliminate most of the casting defects, but is difficult to totally
remove the casting pores, which are likely crack initiation points during
tensile test. As a result, the improvement of extrusion on die cast samples
is largely limited to internal defects . On the other hand, liquid forged
samples are less likely to suffer from the casting defects, including porosity
and hot tearing. Most of the previous research on the flammability
and mechanical properties of Mg alloys are limited to Ca additions
below 4 wt.%. The combination of liquid forging and hot extrusion processes
for non-flammable Mg alloys with Ca additions was not studied
yet. As a result, this work is trying to fill the manufacturing gap and to
further improve the properties and widen the applications for AZ91 Mg
alloy. The microstructure analysis, ignition testing and mechanical properties
measurements of the alloys were conducted and discussed to analyse
the influence of various Ca additions and manufacturing processes.