Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C23/00—Alloys based on magnesium
  • C22C23/02—Alloys based on magnesium with aluminium as the next major constituent

Definitions

• the present invention relates to a magnesium alloy having excellent flame retardancy and toughness.
• Magnesium alloy is known as a lightweight material, and is used for mobile parts such as automobiles and mobile personal computers.
• AM50 is used for a member requiring toughness such as a handle.
• the magnesium alloy may be ignited in a molten state at the time of casting and, once ignited, has poor self-extinguishing properties. For this reason, a magnesium alloy having excellent flame retardancy has been demanded. Further, in order to widen the range of use as members, it is required to further improve mechanical characteristics.
• Patent Document 1 proposes a casting magnesium alloy to which Ca and Y are added. It has been shown that these elements form an oxide film on the surface of the molten metal and improve the flame retardancy (ignition resistance).
• an object of the present invention is to obtain a magnesium alloy exhibiting excellent mechanical properties while improving flame retardancy based on AM50.
• Al is 4.4 to 5.3% by mass
• Ca is 0.2 to 0.5% by mass
• misch metal is 0.2 to 0.4% by mass.
• AlAlso when Al is in the above range, it becomes easy to secure mechanical properties together with other elements. Further, when Mn is contained in the above range, iron derived from a material that may be included as an unavoidable impurity can be easily removed from the alloy in the molten metal.
• a component containing 0.4% by mass or less of Ca and 0.35% by mass or less of misch metal is selected, and a magnesium alloy having further excellent mechanical properties can be obtained.
• This magnesium alloy may contain a limited amount of elements that can be mixed as other unavoidable impurities. However, the total amount must be kept within a range that does not impair the effects of the present invention, and is preferably less than 0.5% by mass, and the content per one element is less than 0.1% by mass. Is preferred.
• a magnesium alloy having excellent flame retardancy and excellent mechanical properties can be obtained.
• This magnesium alloy reduces the possibility of ignition during casting, so that it is easy to cast, and a magnesium alloy member obtained by casting has excellent mechanical properties.
• the present invention is a magnesium alloy having excellent flame retardancy and mechanical properties.
• the magnesium alloy preferably has an Al content of 4.4% by mass or more.
• Al has an effect of improving the tensile strength of the magnesium alloy, and if less than 4.4% by mass, the effect is insufficient.
• the content is preferably 5.3% by mass or less. If the amount of Al is too large, the elongation of the magnesium alloy tends to decrease easily, and if it exceeds 5.3% by mass, the tendency is particularly remarkable.
• the Ca content of the magnesium alloy needs to be 0.2% by mass or more.
• Ca can form a strong protective film on the surface of the molten metal when casting a magnesium alloy, and the protective film improves flame retardancy. If the amount is less than 0.2% by mass, the formation of the protective film is insufficient, and the effect of improving the flame retardancy is also insufficient. On the other hand, it needs to be 0.5% by mass or less, and preferably 0.35% by mass or less.
• the content of Ca is too large, the wettability of the molten metal increases, the affinity for the furnace wall increases, and the fire becomes easy.
• Mm misch metal
• Ca misch metal
• Mm is less than 0.2% by mass, the combined effect of improving the flame retardancy in combination with Ca becomes insufficient.
• the content of Mm needs to be 0.4% by mass or less. If the Mm is too high, the mechanical properties will deteriorate.
• Mm is an alloy of a rare earth element such as Ce or La, and a commonly used material can be used as a material.
• a commonly used material can be used as a material.
• the individual elements contained in Mm except for Y.
• the content of Y is preferably less than 0.3% by mass of the magnesium alloy, and particularly preferably less than 0.01% by mass.
• the Mn content of the magnesium alloy needs to be 0.1% by mass or more, and preferably 0.25% by mass or more.
• Mn the effect of removing iron contained in the molten metal at the time of casting is exhibited.
• the Mn content needs to be 0.6% by mass or less, and preferably 0.35% by mass or less. If the amount of Mn is too large, an intermetallic compound with Al and the simple substance of Mn tend to precipitate, and if it exceeds 0.6% by mass, this problem cannot be ignored.
• the magnesium alloy may contain Be in a range of 5 ppm to 15 ppm.
• Be By containing Be, the flame retardancy can be further improved. Further, from the viewpoint of the influence on the human body, it is desirable that the content be 15 ppm or less.
• the magnesium alloy may contain, in addition to Mg as a residue, elements other than the above, which are impurities, as long as the effects of the present invention are not impaired.
• the content is preferably suppressed to such a degree that it is contained as inevitable impurities that are inevitably contained due to problems in raw materials and production.
• the total amount of the elements that become unavoidable impurities is preferably less than 0.5% by mass, and more preferably less than 0.1% by mass. If there are too many unexpected elements, physical properties may be impaired even in the above element range.
• the content per one element is preferably 0.1% by mass or less, more preferably 0.01% by mass or less, and particularly preferably less than the detection limit.
• Examples of the elements that become inevitable impurities include Fe, Zn, Zr, C, Si, Cu, and Ni. Of these, the amount of Fe removed by Mn is more preferably 0.004% by mass or less.
• the value of the content in the present invention indicates not the ratio in the raw material but the content at the time when the product obtained by the raw material obtained as the alloy or the casting or forging is manufactured.
• the magnesium alloy according to the present invention can be obtained by a general method for manufacturing a magnesium alloy, and when manufacturing a product using the magnesium alloy, it can be manufactured by a general casting method (for example, sand casting). .
• a general casting method for example, sand casting.
• magnesium alloy As a member manufactured from the above magnesium alloy, it can be suitably used for parts requiring elongation, tensile strength, toughness and the like. As a characteristic that can be said of magnesium alloys in general, there is an advantage that they are lighter than other alloys, and a member that is lightweight and has excellent elongation, tensile strength, and toughness can be manufactured. As a member for which such an effect is required and the magnesium alloy can be preferably used, for example, a handle, a seat frame, and an instrument panel can be mentioned.
• the absorbed energy in an impact test according to JIS Z 2224 is 24.0 J or more.
• Comparative Example 2 is AM50 in the existing standard.
• Test pieces were cast so as to have the component ratios shown in each example of Table 3 below.
• the Charpy impact value of this test piece was measured using a Charpy impact tester (manufactured by Mori Testing Machine Co., Ltd.) (JIS Z 2242 (corresponding to ISO148-1)), test temperature 20 ° C., sample temperature 20 ° C. ).
• Table 3 shows the values.
• a measured absorption energy of 24.0 J or more was evaluated as ⁇ .
• Test pieces were cast so as to have the component ratios shown in each example of Table 4 below.
• the test specimen was subjected to a neutral salt spray test (JIS Z 2371 (corresponding to ISO9227)) using a combined cycle tester (manufactured by Itabashi Rika Kogyo Co., Ltd.), and the corrosion loss after 24 hours was measured.
• Table 4 shows the values. ⁇ indicates that the corrosion weight loss was 0.25% or less.
• the alloy of Example 1 was not significantly different from Comparative Example 2 which is AM50 which is a conventional alloy, and it was confirmed that the alloy can be used without any problem in terms of corrosion resistance.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
• Powder Metallurgy (AREA)

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• 2019
  • 2019-12-18 WO PCT/JP2019/049669 patent/WO2020054880A2/ja active Application Filing
• 2020
  • 2020-12-16 WO PCT/JP2020/047020 patent/WO2021125239A1/ja active Application Filing
  • 2020-12-16 CN CN202080084556.7A patent/CN115066511B/zh active Active
  • 2020-12-16 JP JP2021565627A patent/JP7462190B2/ja active Active

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