Magnesium-lithium alloy, rolled material, molded article, and process for producing same

Abstract

The present invention provides a very lightweight magnesium-lithium alloy which has both corrosion resistance and cold workability balanced at high levels, a certain degree of tensile strength, low surface electrical resistivity, as well as a rolled material and a formed article made of the alloy, and a method of producing the alloy, by means of a magnesium-lithium alloy containing not less than 10.5 mass % and not more than 16.0 mass % Li, not less than 0.50 mass % and not more than 1.50 mass % Al, and the balance of Mg, and having an average crystal grain size of not smaller than 5 m and not larger than 40 m, a tensile strength of not lower than 150 MPa, and a surface electrical resistivity of not higher than 1 as measured with an ammeter by pressing a cylindrical two-point probe with a pin-to-pin spacing of 10 mm and a pin tip diameter of 2 mm (contact surface area of one pin is 3.14 mm.sup.2), against an alloy surface at a load of 240 g.

Claims

1. A magnesium-lithium alloy comprising not less than 10.5 mass % and not more than 16.0 mass % Li, not less than 0.50 mass % and not more than 1.50 mass % Al, not less than 0.10 mass % and not more than 0.50 mass % Ca, and the balance of Mg, wherein said alloy does not comprise more than 0.005 mass % of Cu, and wherein said alloy has an average crystal grain size of not smaller than 5 m and not larger than 40 m, a tensile strength of not lower than 150 MPa, and a surface electrical resistance of not higher than 1 as measured with an ammeter by pressing a cylindrical two-point probe with a pin-to-pin spacing of 10 mm and a pin tip diameter of 2 mm (contact surface area of one pin is 3.14 mm.sup.2), against an alloy surface at a load of 240 g.

2. The magnesium-lithium alloy according to claim 1, wherein said average crystal grain size is not smaller than 5 m and not larger than 20 m, and said tensile strength is not lower than 150 MPa and not higher than 180 MPa.

3. A magnesium-lithium alloy comprising not less than 10.5 mass % and not more than 16.0 mass % Li, not less than 0.50 mass % and not more than 1.50 mass % Al, not less than 0.10 mass % and not more than 0.50 mass % Ca, and the balance of Mg, wherein said alloy does not comprise more than 0.005 mass % of Cu, and wherein said alloy has an average crystal grain size of not smaller than 5 m and not larger than 40 m, a Vickers hardness (HV) of not lower than 50, and a surface electrical resistance of not higher than 1 as measured with an ammeter by pressing a cylindrical two-point probe with a pin-to-pin spacing of 10 mm and a pin tip diameter of 2 mm (contact surface area of one pin is 3.14 mm.sup.2), against an alloy surface at a load of 240 g.

4. The magnesium-lithium alloy according to claim 3, wherein said average crystal grain size is not smaller than 5 m and not larger than 20 m, and said HV is not lower than 50 and not higher than 70.

5. The magnesium-lithium alloy according to claim 1, wherein said content of Li is not less than 13.0 mass % and not more than 15.0 mass %.

6. A method for producing a magnesium-lithium alloy of claim 1, comprising the steps of: (a) cooling and solidifying a raw material alloy melt into an alloy ingot, said raw material alloy melt comprising not less than 10.5 mass % and not more than 16.0 mass % Li, not less than 0.50 mass % and not more than 1.50 mass % Al, not less than 0.10 mass % and not more than 0.50 mass % Ca, and the balance of Mg, said raw material alloy melt not comprising more than 0.005 mass % of Cu, (b) subjecting said alloy ingot to cold plastic working at a rolling reduction of not lower than 30%, (c) annealing a plastic-worked alloy at 170 to lower than 250 C. for 10 minutes to 12 hours, or at 250 to 300 C. for 10 seconds to 30 minutes, and (d) treating a surface of a resulting alloy with an electrical resistance-lowering solution of an inorganic acid containing aluminum and zinc metal ions.

7. The method according to claim 6 further comprising, after said step (d), (e) following surface conditioning, immersing said alloy in a chemical conversion-coating solution containing a fluorine compound for chemical conversion coating.

8. The method according to claim 6, wherein said electrical resistance-lowering solution comprises 0.021 to 0.47 g/l aluminum and 0.0004 to 0.029 g/l zinc.

9. The method according to claim 7, wherein a 3.33 to 40 g/l aqueous solution of acidic ammonium fluoride is used as said chemical conversion-coating solution containing a fluorine compound.

10. A rolled material made of a magnesium-lithium alloy according to claim 1.

11. A formed article made of a magnesium-lithium alloy according to claim 1.

Description

EMBODIMENTS OF THE INVENTION

(1) The present invention will now be explained in more detail with reference to Examples, which are not intended to limit the present invention.

Test Alloy 1

(2) A raw material having a composition of 14.0 mass % Li, 1.00 mass % Al, 0.30 mass % Ca, and the balance of Mg, was heated to melt into an alloy melt. The alloy melt was cast into a metal mold of 55 mm300 mm500 mm to prepare an alloy ingot. The composition of the obtained alloy was determined by the ICP atomic emission spectrochemical analysis. The results are shown in Table 1.

(3) The alloy ingot thus obtained was heat treated at 300 C. for 24 hours and the surface was cut to prepare a slab of 50 mm thick for rolling. This slab was rolled at 350 C. into a board thickness of 2 mm, and then at room temperature into a board thickness of 1 mm at a rolling reduction of 50%, to thereby obtain a rolled product. The rolled product was annealed at 230 C. for 1 hour to produce a rolled material.

(4) The average crystal grain size, the tensile strength, and the Vickers hardness of the rolled material thus obtained were measured according to the methods discussed above. Corrosion resistance was evaluated by a 5% salt water immersion test, and cold workability was evaluated by determining the limiting drawing ratio (LDR) at room temperature. The results are shown in Table 1.

(5) The 5% salt water immersion test was performed by repeating three cycles of the steps of immersing a test piece, which had been surface polished and washed with acetone, in a salt water containing 5% sodium chloride at a solution temperature of 255 C. for 8 hours, and leaving the test piece in the air for 16 hours. The evaluation was made by determining the mass change per unit surface area after the test as a degree of corrosion, and calculating a ratio of the degree with respect to the degree of corrosion of AZ31 material, which was tested in parallel as a comparison, being 100.

(6) The conditions for determining the LDR were as follows: punch diameter: 40 mm; die diameter: 42.5 mm; die shoulder radius: 8 mm; fold pressure: 12 kN; punch shoulder radius: 4 mm; lubricant: molybdenum disulfide; punch speed: 3 mm/sec.

Comparative Example 1

(7) A rolled material was prepared and evaluated in the same way as Test Alloy 1, except that the composition of the raw material was 14.0 mass % Li, 1.00 mass % Al, and the balance of Mg, and the annealing at 230 C. for 1 hour was changed to at 150 C. for 1 hour. The results are shown in Table 2.

Test Alloys 2 to 16 and Comparative Examples 2 to 11

(8) A rolled material was prepared in the same way as Test Alloy 1, except that the composition of the raw material was changed so as to provide the alloy composition as shown in Tables 1 and 2, and the production conditions were changed as shown in Tables 1 and 2. The obtained rolled material was evaluated in the same way as Test Alloy 1. The results of Test Alloys are shown in Table 1, and those of Comparative Examples in Table 2.

(9) TABLE-US-00001 TABLE 1 Degree of Board Board Alloy composition (mass %) Average Corrosion thickness Cold thickness Other crystal (5% salt after hot rolling after cold Annealing than Li, grain Tensile Vickers water Test rolling reduction rolling Temp. Time Al, Ca, size strength hardness immersion Alloy (mm) (%) (mm) ( C.) (hr) Li Al Ca and Mg Mg (m) (MPa) (Hv) test) LDR 1 2.0 50 1.0 230 1 13.7 1.04 0.26 Balance 15 156 58 65 2.05 2 1.5 33 1.0 240 1 13.8 1.05 0.27 Balance 18 175 64 71 2.05 3 4.0 75 1.0 240 10 13.6 1.03 0.30 Balance 35 185 72 101 2.00 4 2.0 50 1.0 240 5 13.8 1.03 0.30 Balance 38 152 57 121 2.00 5 2.0 50 1.0 220 1 12.1 1.02 0.28 Balance 16 161 60 63 1.70 6 2.0 50 1.0 220 1 13.2 0.99 0.32 Balance 18 159 59 66 1.95 7 2.0 50 1.0 220 1 14.8 0.97 0.31 Balance 33 161 60 97 1.90 8 2.0 50 1.0 220 1 15.5 1.05 0.25 Balance 35 151 56 215 2.15 9 2.0 50 1.0 230 1 13.7 1.04 0.00 Balance 40 181 68 156 2.00 10 2.0 50 1.0 220 1 13.1 0.89 0.20 Zn 1.20 Balance 37 151 55 105 2.05 11 2.0 50 1.0 220 1 13.4 0.97 0.15 Mn 0.35 Balance 20 173 63 61 1.90 12 2.0 50 1.0 220 1 12.5 0.95 0.10 Ce 1.53 Balance 25 165 61 62 1.85 13 2.0 50 1.0 220 1 12.3 0.81 0.13 Y 0.51 Balance 18 166 61 63 1.90 14 20.0 95 1.0 180 1 13.7 0.97 0.23 Balance 19 165 60 91 2.05 15 10.0 90 1.0 200 1 13.4 0.96 0.29 Balance 17 157 58 66 2.05 16 20.0 95 1.0 200 1 13.7 1.04 0.00 Balance 23 159 59 83 2.05

(10) TABLE-US-00002 TABLE 2 Degree of Board Board Corrosion thickness Cold thickness Average (5% salt after hot rolling after cold Annealing crystal Tensile Vickers water Comp. rolling reduction rolling Temp. Time Alloy composition (mass %) grain size strength hardness immersion Ex. (mm) (%) (mm) ( C.) (hr) Li Al Ca Mg (m) (MPa) (Hv) test) LDR 1 2.0 50 1 150 1 13.5 1.04 0.00 Balance 25 131 16 1577 1.95 2 2.0 50 1 260 1 13.7 0.98 0.00 Balance 51 161 60 317 1.95 3 2.0 50 1 230 1 13.9 0.00 0.00 Balance 39 101 36 2652 2.10 4 2.0 50 1 230 1 13.7 2.10 0.00 Balance 38 174 64 81 1.50 5 2.0 50 1 220 1 10.2 1.05 0.00 Balance 18 174 64 64 1.40 6 2.0 50 1 230 1 16.5 1.04 0.00 Balance 40 131 47 510 2.20 7 2.0 50 1 130 1 13.6 1.00 0.26 Balance 232 72 2781 1.65 8 1.3 23 1 160 1 13.3 0.95 0.00 Balance 185 68 2472 1.60 9 1.3 23 1 250 1 13.3 0.95 0.00 Balance 51 159 59 334 1.95 10 20.0 95 1 160 1 13.7 0.97 0.00 Balance 21 141 49 1375 1.90 11 20.0 95 1 260 1 13.7 0.97 0.00 Balance 59 165 61 317 1.70

(11) As can be seen from the results shown in Table 1, when all of the cold rolling reduction, the annealing temperature, and the alloy composition were within the ranges defined in the production method according to the present invention, the average crystal grain size, the tensile strength, and the Vickers hardness fall within the ranges defined for the MgLi alloy according to the present invention, and excellent corrosion resistance and cold workability (results of LDR) were achieved.

(12) As can be seen from the results shown in Table 2, in Comparative Examples 1 and 2, only the annealing temperature was outside the range defined in the production method according to the present invention, which resulted in good cold workability but poor corrosion resistance. In Comparative Example 2, though the alloy composition, the tensile strength, and the Vickers hardness were within the ranges defined for the MgLi alloy of the present invention, the average crystal grain size was too large, and thus the desired properties could not be obtained.

(13) Comparative Example 3 demonstrates that absence of Al in the alloy composition alone resulted in inferior corrosion resistance.

(14) Comparative Examples 4 and 5 demonstrate that only the alloy composition with too high an Al content or too low a Li content being outside the range defined in the production method of the present invention, the cold workability was significantly poor, while the tensile strength, the Vickers hardness, and the average crystal grain size were within the ranges defined for the MgLi alloy of the present invention.

(15) Comparative Example 6 demonstrates that only the alloy composition of too high a Li content being outside the range defined in the production method of the present invention, the corrosion resistance was poor.

(16) Comparative Example 7 demonstrates that only the annealing temperature of 130 C. for 1 hour being lower than the range defined in the production method of the present invention, recrystallization did not occur, and the cold workability and the corrosion resistance were both inferior, while the tensile strength and the Vickers hardness fall within the ranges defined for the MgLi alloy of the present invention.

(17) Comparative Example 8 demonstrates that the cold rolling reduction and the annealing temperature being outside the ranges defined in the production method of the present invention, recrystallization did not occur, and the cold workability and the corrosion resistance were both inferior, while the tensile strength and the Vickers hardness fall within the ranges defined for the MgLi alloy of the present invention.

(18) Comparative Example 9 demonstrates that the cold rolling reduction being outside the range defined in the production method of the present invention, the average crystal grain size was too large, and the corrosion resistance was poor, while the tensile strength and the Vickers hardness fall within the ranges defined for the MgLi alloy of the present invention.

(19) Comparative Example 10 demonstrates that even with a high cold rolling reduction, when the annealing temperature of 160 C. for 1 hour was lower than the range defined in the production method of the present invention, the tensile strength and the Vickers hardness did not fall within the ranges defined for the MgLi alloy of the present invention, and the corrosion resistance was poor, while recrystallization occurred.

(20) Comparative Example 11 demonstrates that even with a high cold rolling reduction, when the annealing temperature of 260 C. for 1 hour was outside the range defined in the production method of the present invention, the average crystal grain size was too large and the corrosion resistance was poor, while the tensile strength and the Vickers hardness fall within the ranges defined for the MgLi alloy of the present invention.

Examples 1 to 9 and Comparative Examples 12 to 29

(21) As an article to be treated, a rolled MgLi alloy obtained by the method similar to that of Test Alloy 16 of 50 mm long50 mm wide1.0 mm thick was provided as a test piece.

(22) The test piece was first subjected to degreasing by immersion for 8 minutes in a strong alkaline aqueous solution (30% aqueous solution of GFMG15SX (tradename) manufactured by MILLION CHEMICALS CO., LTD.) maintained at 80 C.

(23) The degreased test piece, after being washed with water, was treated with an electrical resistance-lowering solution as shown in Table 3. The electrical resistance-lowering solution was prepared by adding zinc oxide and monobasic aluminum phosphate to phosphoric acid so that the contents of zinc and aluminum in the solution were adjusted to the amounts as shown in Table 3.

(24) The test piece, after being washed with water, was then subjected to surface conditioning by immersion for 2 minutes in a strong alkaline aqueous solution (45% aqueous solution of GFMG15SX (trade name) manufactured by MILLION CHEMICALS, CO., LTD.) maintained at 60 C.

(25) The test piece, after being washed with water, was then immersed in a chemical conversion-coating solution, which was a ammonium fluoride aqueous solution containing a fluoride as shown in Table 3, at 60 C. for 180 seconds. The chemical conversion-coating solution was adjusted before use such that the fluorine content of the ammonium fluoride was as shown in Table 3.

(26) TABLE-US-00003 TABLE 3 Electrical Resistance- Chemical Conversion- Lowering Solution Coating Solution Zn (g/l) Al (g/l) F (g/l) Examples 1 0.0004 0.021 13.33 2 0.0004 0.14 13.33 3 0.0004 0.47 13.33 4 0.008 0.021 13.33 5 0.008 0.14 13.33 6 0.008 0.47 13.33 7 0.029 0.021 13.33 8 0.029 0.14 13.33 9 0.029 0.47 13.33 Comparative 12 0.00038 0.021 13.33 Examples 13 0.00038 0.14 13.33 14 0.00038 0.47 13.33 15 0.03 0.021 13.33 16 0.03 0.14 13.33 17 0.03 0.47 13.33 18 0.004 0.018 13.33 19 0.008 0.018 13.33 20 0.029 0.018 13.33 21 0.004 0.48 13.33 22 0.008 0.48 13.33 23 0.029 0.48 13.33 24 0 0.021 13.33 25 0 0.14 13.33 26 0 0.47 13.33 27 0.0004 0 13.33 28 0.008 0 13.33 29 0.029 0 13.33

(27) Four of the test pieces, which had been washed with water and dried, were prepared for one experimental condition, two of which were subjected to evaluations of surface electrical resistance and bare corrosion resistance.

(28) The remaining two were subjected to typical baking finishing for magnesium alloys in the following matter. Each test piece was coated with an epoxy primer for undercoating, baked at 150 C. for 20 minutes, coated with an acrylic lacquer for top coating, and baked at 150 C. for 20 minutes, to thereby make the total film thickness of 40 to 50 m.

(29) The coated test pieces were subjected to evaluations of coating performance.

(30) Each evaluation was made as follows:

(31) <Surface Electrical Resistance>

(32) The surface electrical resistance was measured with Loresta-EP two-point A-probe (manufactured by MITSUBISHI CHEMICAL ANALYTECH CO., LTD., pin-to-pin spacing of 10 mm, pin tip diameter of 2.0 mm (contact surface area of one pin of 3.14 mm.sup.2), pressure of springs of 240 g) by pressing the pins against the surface of the test piece in the middle, upper, or lower portion. Three measurements were made for each test piece, and the average of the total of six measurements for the two test pieces was obtained.

(33) The measurement at 240 g load was made by pressing the two-point probe against the surface of the test piece until the pins were retracted against the pressure of the springs. A surface electrical resistance of not higher than 0.5 was indicated with , higher than 0.5 and lower than 1.0 with , 1.0 to lower than 1000 with , and 1000 or higher or if unmeasurable even only once, with X.

(34) The measurement at 60 g load was made by pressing the two-point probe (body weight 30 g) with an additional 30 g load against the surface of the test piece. A surface electrical resistance of not higher than 1.0 was indicated with , higher than 1.0 and lower than 10.0 with , 10.0 to lower than 1000 with , and 1000 or higher or if unmeasurable even only once, with X.

(35) The measurement at 240 g load is a simulation of the case wherein the grounding wires are fixed to the surface of the casing parts by means of screws, whereas the measurement at 60 g load is a simulation of the case wherein the grounding wires are fixed to the surface of the casing parts by means of adhesive tapes.

(36) <Bare Corrosion Resistance Test>

(37) In accordance with the method of salt spray testing (SST testing) provided in JIS Z 2371, a test piece was placed in a test vessel set at 35 C., sprayed with 5% salt water, taken out after 24 hours, washed on the surface with water, and measured for the surface rust area (%). A surface rust area of 0% was indicated with , not more than 5% with , more than 5% and less than 30% with , and 30% and more with X.

(38) <Bare Humidity Resistance Test>

(39) A test piece was placed in a chamber with constant temperature and humidity set at 50 C. and 90% humidity, taken out after 120 hours, and measured for the surface rust area (%). A surface rust area of 0% was indicated with , not more than 5% with , more than 5% and less than 30% with , and 30% and more with X.

(40) <Coating Corrosion Resistance Test>

(41) A coated test piece was incised with a cutter knife.

(42) In accordance with the method of salt spray testing (SST testing) provided in JIS Z 2371, the incised test piece was placed in a test vessel set at 35 C., sprayed with 5% salt water, taken out after 240 hours, washed on the surface with water, and dried. An adhesive tape was applied to the dried incised portion of the coating and peeled off. The maximum width (mm) of the coating thus peeled on one side from the incision was measured. A width of less than 2.0 mm was indicated with , 2.0 mm to less than 3.0 mm with , 3.0 mm to less than 6.0 mm with , and 6.0 mm and more with X.

(43) <Coating Waterproof Test>

(44) A coated test piece was placed in boiling water (100 C.) for 60 minutes, taken out, and wiped on the surface to remove the residual surface moisture, and left at room temperature for 1 hour. Then the test piece was cross-cut on the surface by 1 mm, an adhesive tape was applied thereto and peeled, and the area of the coating peeled off was determined. An area of 0% was indicated with , not more than 5% with , more than 5% and less than 30% with , and 30% and more with X.

(45) The results are shown in Table 4.

(46) TABLE-US-00004 TABLE 4 Surface Electrical Resistance Bare Corrosion Resistance Test Coating Performance Evaluation 240 g 60 g SST Testing Humidity Test (120 H) SST Testing Boiling Water Test Examples 1 0.92 9.8 within 5% within 5% 2.2 mm little 2 0.48 2.8 within 5% little 2.2 mm little 3 0.50 8.2 within 5% little 2.3 mm within about 5% 4 0.48 3.0 within 5% within 5% 2.2 mm little 5 0.32 0.78 within 5% little 2.1 mm little 6 0.33 0.82 within 5% little 2.2 mm within about 5% 7 0.86 8.8 within 5% within 5% 2.2 mm little 8 0.41 4.8 within 5% within 5% 2.3 mm little 9 0.98 9.9 within 5% within 5% 2.7 mm within about 5% Comparative 12 OVER X OVER X within 5% within 5% 2.2 mm within about 5% Examples 13 .sup.28 OVER X within 5% within 5% 2.2 mm within about 5% 14 392 OVER X within 5% within 5% 2.3 mm about 15% 15 OVER X OVER X within 5% about 10% 2.2 mm within about 5% 16 OVER X OVER X within 5% about 10% 2.2 mm within about 5% 17 OVER X OVER X within 5% about 30% 3.1 mm about 20% 18 OVER X OVER X within 5% about 10% 2.2 mm within about 5% 19 .sup.35 OVER X within 5% about 20% 2.2 mm within about 5% 20 OVER X OVER X within 5% about 40% X 2.2 mm within about 5% 21 .sup.28 OVER X within 5% about 30% 2.4 mm about 15% 22 0.98 895 within 5% about 25% 3.1 mm about 10% 23 OVER X OVER X within 5% about 30% 3.3 mm about 60% X 24 OVER X OVER X within 5% about 15% 2.4 mm about 15% 25 OVER X OVER X within 5% about 20% 2.6 mm about 10% 26 OVER X OVER X within 5% about 20% 3.2 mm about 70% X 27 OVER X OVER X within 5% about 20% 2.4 mm within about 5% 28 OVER X OVER X within 5% about 30% 2.3 mm within about 5% 29 OVER X OVER X within 5% about 50% X 2.7 mm about 10%

(47) The results in Table 4 show that the test pieces according to the present invention had low surface electrical resistance and excellent bare corrosion resistance and coating adhesion.

Examples 10 to 12 and Comparative Examples 30 to 33

(48) Test pieces of Examples 14 to 20 were prepared in the same way as in Example 5, except that the chemical conversion-coating solutions as shown in Table 5 were used.

(49) Here, the chemical conversion-coating solutions were adjusted such that the fluorine and aluminum contents of the ammonium fluoride and the monobasic aluminum phosphate, respectively, were as shown in Table 1.

(50) The obtained test pieces were measured for the surface electrical resistance, the bare corrosion resistance, and the coating performance in the same way as in the above Examples.

(51) The results are shown in Table 5.

(52) TABLE-US-00005 TABLE 5 Electrical Resis- Chemical tance-Lowering Conversion Surface Bare Corrosion Coating Performance Solution Coating Solution Electrical Resistance Test Evaluation Zn Al F Al Resistance SST Humidity SST Boiling (g/l) (g/l) (g/l) (g/l) 240 g 60 g Testing Test (120 H) Testing Water Test Ex. 10 0.008 0.14 3.33 0 0.38 0.45 within 5% within 5% 2.5 mm about 5% 11 0.008 0.14 13.33 0 0.32 0.78 within 5% little 2.1 mm little 12 0.008 0.14 40 0 0.89 8.4 within 5% little 2.9 mm about 5% Comp. 30 0.008 0.14 3.26 0 0.48 3.0 about 10% about 10% 2.6 mm little Ex. 31 0.008 0.14 40.66 0 0.98 10.1 within 5% little 3.1 mm about 10% 32 0.008 0.14 13.33 0.09 0.93 10.5 within 5% little 2.0 mm little 33 0.008 0.14 13.33 0.45 1.5 OVER X within 5% little 1.5 mm little

(53) From the results shown in Table 5, it was confirmed that, in order to obtain a MgLi alloy having low surface electrical resistance and excellent bare corrosion resistance and coating adhesion, the amounts of zinc and aluminum contained in the electrical resistance-lowering solution and the amount of fluorine contained in the chemical conversion-coating solution have to be maintained at predetermined amounts.

(54) Further experiments were conducted in the same way as in Examples 1 to 12 above, except that Test Alloy 16 was replaced with each of the remaining Test Alloys 1 to 15. The results show correlation between the degree of corrosion determined by the 5% salt water immersion test as shown in Table 1 and the surface electrical resistance, the bare corrosion resistance, and the coating corrosion resistance. That is, it was confirmed that a test alloy exhibiting a better result in the degree of corrosion determined by the 5% salt water immersion test as shown in Table 1, also had better surface electrical resistance, bare corrosion resistance, and coating corrosion resistance.

INDUSTRIAL APPLICABILITY

(55) The magnesium-lithium alloy and the method for producing the same according to the present invention may be used for casings of various electronic devices which need to provide ground.