Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
  • C22C21/10—Alloys based on aluminium with zinc as the next major constituent

Definitions

• the aluminum alloys which are widely used as construction materials are light in weight as well as considerably strong.
• the alloys have defects in actual use thereof in such points that their hardness are far lower than those of iron and steel materials or other nonferrous materials such as copper alloys, etc.
• the aluminum alloys are relatively soft, and therefore the surfaces of the alloys are not only readily scratched, but also deformed or worn away. Accordingly they cannot be used as screw nuts, and other parts of machines.
• Table 1 shows the comparison of hardness between typical constructional metals and practically used high tension aluminum alloys.
• the object of the present invention is to obtain an aluminum material whose hardness is higher than any other commercial aluminum alloys by special treatments to 3,531,337 Patented Sept. 29, 1970 which the chemical ingredients of the aluminum alloy is subjected, and to make the aluminum material applicable as such screws, viz nuts, springs, and other parts of machines that require high abrasion resistance property as those of iron and steel.
• the chemical ingredients contained in the present alloys are 2.67.8% zinc and 0.6-3.8% magnesium as the principal additive elements which mainly act as the components of age hardening.
• the present alloys contain 02-12% of each of iron and nickel of transition metals of Group IV of the Periodic Table, 0.1-1.2% manganese, and 0.5% chromium.
• the alloys contain ODS-1.2% zirconium of Group IVa (in some cases, this being replaced in part with titanium 0r hafnium), 0.0050.3% boron which is a metalloid, and 0.050.85% silicon, and the remainder of aluminum.
• the characteristics points in treating the alloys of the present invention are in that the molten metal is kept at elevated temperature after the melting of the alloys and in the nitrogenization of alloy which is carried out by passing nitrogen or a nitrogen-containing gas, for example, ammonium into the molten alloy to react with each other or by reacting a nitrogen-containing compound such as an ammonium-containing compound or a nitrate, so that zirconium of Group IV (in some cases, titanium or hafnium are included) is dispersion hardened as a zirconium nitride. Boron, also, forms in part boron nitride, and promotes the strengthening of dispersion.
• nitrogen or a nitrogen-containing gas for example, ammonium into the molten alloy to react with each other or by reacting a nitrogen-containing compound such as an ammonium-containing compound or a nitrate
• zirconium of Group IV in some cases, titanium or hafnium are included
• Boron also, forms in part boron
• iron, nickel and cobalt of Group IV of the Periodic Table form intermetallic compounds in the aging aluminum alloys.
• 1% addition thereof is destructive, the simultaneous addition of at least two elements, however, hardly damaging the aging hardness.
• Manganese has an effect to improve the fineness of grain size of crystal and toughness together with chromium, and since chromium increases the corrosion resistance, against especially stress corrosion, the addition of a small amount of chromium is effective. Also, the addition of a small amount of silicon which already exists in the raw metal contributes to the age hardening.
• the present invention is an alloy melt prepared by adding the above-mentioned various elements to the aging aluminum-zinc-magnesium system, and subjecting the system to the nitriding treatment.
• the greatest characteristics of the present invention is to produce an alloy having hot and cold workabilities and at the same time such a high hardness produced by solution treatment and age hardening (T treatment) or the work hardening thereafter that has never been observed.
• the hardness reaches about 180 in the aging hardening conditions, which is the highest hardness in the conventional aluminum alloy.
• This hardness matches the hardness of hardened phosphorus bronze or that of medium carbon steel.
• the aging hardening of the alloy of the present invention is stopped before the highest possible hardness is obtained by this treatment, it is possible to produce an incredibly high hardness of Vickers hardness 200 or more by applying about 50% cold work to this alloy.
• the alloy of a Vickers hardness of 205 is obtained in Example 1, and a Vickers hardness of 201, in Example 2, these hardness being about twice of that imparted to duralumin 2017, and matching the hardness of copper alloy naturally or even that'of iron material.
• the present alloy is, as explained above, an alloy having such a high hardness that ever seen as a wrought aluminum alloy having workability and as aluminum base alloy treated with T treatment.
• the present alloy also shows an extremely high hardness as casting material, and is further improved by solution and aging treatments (T treatment) after the alloy was cast.
• composition of the example and the aging hardness under such treatment condition as described above are as shown in Table 4.
• the alloy of the present invention shows, as illustrated above, a considerable hardness (a Vickers hardness of 127) under casting condition.
• a Vickers hardness of 127 By the T treatment, the hardness of the present alloy reaches a Vickers hardness which is as high as 180, so that the aluminum alloy excellent in abrasion resistance is obtained as a casting product.
• the aluminum alloy high in hardness to which the present invention relates demonstrates excellent properties produced by such a composition as was shown in the previous example, and by various treatments suited for the composition.
• zirconium in some cases, titanium or hafnium being included
• boron become, as already explained above, dispersion particles by forming nitrides thereof by the solution treatment, and perform the action of dispersion strengthening by blocking the move of dislocation line.
• the suitable amount of zirconium or a metal of its group is 0.051.2%
• the amount of boron 0.0050.3%.
• Transition metal iron, nickel and cobalt of Group IV of the Periodic Table have very little solid solubility in aluminum, concentrate around crystalline grain boundary and strengthen the neibourfood of grain boundary by increasing the dislocation density, and promote the Work hardenings.
• the single use of these metals is in some cases, as described above, destructive to the age hardening, while the simultaneous use of at least two elements of these do not damage the age hardening, so that these elements are added simultaneously for these reasons.
• the suitable amount of each of these ingredients is in the range of 0.21.2%. When the amount is smaller than the lower limit, there is no practical effect, and when the amount exceeds the upper limit, the corrosion resistance is damaged, toughness, also, being reduced.
• Chromium and manganese of the transition metals of Group IV check the deterioration of the grain boundary by making the crystalline grains finer similarly to the action of iron with an effect that corrosion resistance is increased. Both elements are very useful and especially when chromium is contained at 0.5% or below, the ingredient is effective particularly to casting alloys. 01-- 1.2% manganese has an effect of improving malleability. Silicon promotes the age hardening, and, similarly to the above-mentioned iron and other transition metals, has an effect of checking the deterioration of the grain boundary. The addition of a large amount of silicon, however, damages workability. Its suitable amount is in the range of ODS-0.88%.
• An aged aluminum alloy product high in hardness and abrasion resistance characterized by elevating the hardness of an alloy containing 2.6-7.8% zinc, 0.63.8% magnesium, 0.21.2% iron, 0.2-1.2% nickel and/or cobalt, 0.1-1.2% manganese, 0.5 or below of chromium, 0.05-1.2% of at least one element from the group consisting of zirconium, hafnium and titanium, said element being combined with nitrogen in the product to form dispersed nitrides; 0.0050.3% boron, at least a part of which is combined with nitrogen in the product to form dispersed nitrides, and 0.03-0.85% silicon, and the remainder of aluminum, said product having been made by subjecting said alloy to a nitriding treatment while in the molten state, and then to a solution heat treatment at a temperature in the range of 450490 C. as cast or after working and thereafter to an aging treatment at a temperature of to C. to produce a high hardness, and, in some cases
• An alloy product of claim 1 comprising 5.0% Zn, 2.0% Mg, 0.4% Ni, 0.35% Zr, 0.4% Fe, 0.006% B, 04% Si and 0.6% Mn.
• An alloy product of claim 1 comprising 5.0% Zn, 2.0% Mg, 0.2% Ni, 0.35% Zr, 0.8% Fe, 0.6% Co, 0.1% B, 0.18% Si and 0.3% Mn.
• An alloy product of claim 1 comprising 5.0% Zn, 2.0% Mg, 0.55% Ni, 0.35% Zr, 0.7% Fe, 0.1% Cr, 0.1% B, 0.35% Si and 0.7% Mn.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)
• Heat Treatment Of Steel (AREA)

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• 1967
  • 1967-12-26 FR FR1548155D patent/FR1548155A/fr not_active Expired
  • 1967-12-26 US US693100A patent/US3531337A/en not_active Expired - Lifetime
  • 1967-12-27 GB GB58633/67A patent/GB1215817A/en not_active Expired
  • 1967-12-27 CH CH1821167A patent/CH488808A/fr not_active IP Right Cessation
  • 1967-12-27 DE DE19671608190 patent/DE1608190B1/de active Pending

Patent Citations (7)

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