Enhanced electromagnetic interference shielding in ZK60 magnesium alloy by aging precipitation

Electromagnetic interference shielding, hardness, and electrical conductivity measurements were employed to evaluate the effect of aging precipitation on shielding characteristics of ZK60 magnesium alloy. During artificial aging MgZn2 phase precipitates occurred and the age hardening peak happened at 150 °C for 15 h. Aging precipitation induced enhanced shielding effectiveness as well as tensile strength in the alloy. It is interesting to note that the shielding effectiveness exhibited a rapid increase with increase in aging time until 15 h, but for longer aging time it tended to remain largely unchanged. Artificial aging at 150 °C for 15 h can thus be considered as the optimum heat treatment condition. In this condition, the good combination of superior shielding effectiveness greater than 70 dB and high mechanical properties was achieved. The origin of the attractive electromagnetic interference shielding properties is discussed based on second phase precipitation in the alloy.

► Aging at 150 °C led to a great elevation in shielding capacity due to numerous precipitates.
► Shielding effectiveness increased with aging time until 15 h, but for longer aging time it remained largely unchanged.
► The alloy exhibited excellent shielding effectiveness higher than 70 dB when aging at 150 °C for 15 h.