OEM High Precision Dimension Magnesium Alloy Die Casting Parts. Magnesium alloy die-casting refers to the magnesium alloy in the molten state injected into the mold cavity at high speed and high pressure. AZ91D alloy has low liquid viscosity and good fluidity so it is easy to fill complex structure cavities. And high pressure die casting with magnesium alloy can lowdown the reject ratio of misrun and cold mark. The phone housing is thin and smooth which meets the handiness popular style.