A calcium-bearing magnesium and rare earth element alloy consists essentially of, in mass percent, zinc (Zn): 1-3%; aluminum (Al): 1-3%; calcium (Ca): 0.1-0.4%; gadolinium (Gd): 0.1-0.4%; yttrium (Y): 0-0.4%; manganese (Mn): 0-0.2%; and balance magnesium (Mg).

A calcium-bearing magnesium and rare earth element alloy consists essentially of, in mass percent, zinc (Zn): 1-3%; aluminum (Al): 1-3%; calcium (Ca): 0.1-0.4%; gadolinium (Gd): 0.1-0.4%; yttrium (Y): 0-0.4%; manganese (Mn): 0-0.2%; and balance magnesium (Mg).

Disclosed are a magnesium die casting alloy, and an alloy composition for improving thermal conductivity and electrical conductivity. A magnesium die casting alloy includes an amount of about 0.5 to 2.0 wt % of aluminum (Al) and the balance magnesium (Mg), based on the total weight of the magnesium die casting alloy. Accordingly, an alloy, which has high thermal conductivity and electrical conductivity as compared to a conventional AZ91D magnesium alloy, is obtained.

Disclosed are a magnesium die casting alloy, and an alloy composition for improving thermal conductivity and electrical conductivity. A magnesium die casting alloy includes an amount of about 0.5 to 2.0 wt % of aluminum (Al) and the balance magnesium (Mg), based on the total weight of the magnesium die casting alloy. Accordingly, an alloy, which has high thermal conductivity and electrical conductivity as compared to a conventional AZ91D magnesium alloy, is obtained.

An exemplary embodiment of the present invention relates to a magnesium alloy sheet and a manufacturing method thereof. The exemplary embodiment of the present invention provides a magnesium alloy sheet including 0.5 to 2.1 wt % of Al, 0.5 to 1.5 wt % of Zn, 0.1 to 1.0 wt % of Ca, and a balance of Mg and inevitable impurities, with respect to a total of 100 wt % of the magnesium alloy sheet.

An exemplary embodiment of the present invention relates to a magnesium alloy sheet and a manufacturing method thereof. The exemplary embodiment of the present invention provides a magnesium alloy sheet including 0.5 to 2.1 wt % of Al, 0.5 to 1.5 wt % of Zn, 0.1 to 1.0 wt % of Ca, and a balance of Mg and inevitable impurities, with respect to a total of 100 wt % of the magnesium alloy sheet.

A magnesium alloy containing Al, Sr, Ca, and Mn, with the balance being Mg and inevitable impurities, the magnesium alloy having: a structure having an α-Mg phase, and a precipitate dispersed in at least one of a grain boundary of the α-Mg phase and a cell boundary, the precipitate including: at least one phase selected from a group A consisting of an Al.sub.2Sr phase, an Al.sub.4Sr phase, a (Mg, Al).sub.2Sr phase, and a (Mg, Al).sub.4Sr phase; and at least one phase selected from a group B consisting of an Al.sub.2Ca phase and a (Mg, Al).sub.2Ca phase, the magnesium alloy having, in a cross section, a total area rate of a group A precipitate and a group B precipitate of greater than or equal to 2.5% and less than or equal to 30%.

A magnesium alloy containing Al, Sr, Ca, and Mn, with the balance being Mg and inevitable impurities, the magnesium alloy having: a structure having an α-Mg phase, and a precipitate dispersed in at least one of a grain boundary of the α-Mg phase and a cell boundary, the precipitate including: at least one phase selected from a group A consisting of an Al.sub.2Sr phase, an Al.sub.4Sr phase, a (Mg, Al).sub.2Sr phase, and a (Mg, Al).sub.4Sr phase; and at least one phase selected from a group B consisting of an Al.sub.2Ca phase and a (Mg, Al).sub.2Ca phase, the magnesium alloy having, in a cross section, a total area rate of a group A precipitate and a group B precipitate of greater than or equal to 2.5% and less than or equal to 30%.

A downhole tool comprising magnesium is placed in a well bore in a subterranean formation for performance of a downhole operation. After performance of the downhole operation, rather than mechanically retrieving or removing the tool, at least a portion of the magnesium in the downhole tool is dissolved by contacting the downhole tool with an aqueous ammonium chloride solution.

A downhole tool comprising magnesium is placed in a well bore in a subterranean formation for performance of a downhole operation. After performance of the downhole operation, rather than mechanically retrieving or removing the tool, at least a portion of the magnesium in the downhole tool is dissolved by contacting the downhole tool with an aqueous ammonium chloride solution.