RU2613270C1 - HIGH-STRENGTH ALUMINIUM-BASED WROUGHT ALLOY OF Al-Zn-Mg-Cu-SYSTEM AND ARTICLE MADE THEREOF - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: high-strength Al-based wrought alloys of the Al-Zn-Mg-Cu system and article thereof contain, wt %: 7.8-8.2 Zinc, 2.0-2.4 magnesium, 1.8-2.1 copper, 0.1-0.17 scandium, 0.1-0.14 zirconium, 0.0005-0.001 cerium, 0.01-0.03 titanium, 0.0005-0.001 boron, aluminum and inevitable impurities, including not more than 0.12 iron, no more than 0.11 silicon, no more than 0.02 manganese, not more than 0.02 chromium, - the rest, while hydrogen is present in the alloy in an amount of 0.05-0.3 cm³/ 100 g of metal, and the ratio of magnesium and zinc is from 0.25 to 0.3.

EFFECT: increased strength characteristics, including specific strength of the material.

2 cl, 1 ex, 2 tbl

Description

The present invention relates to the field of metallurgy, in particular to high-strength wrought alloys based on aluminum, intended for use in the form of deformed semi-finished products, mainly extruded, as a structural material.

Known in metallurgy is a high-strength wrought alloy based on aluminum grade V96C of the Al-Zn-Mg-Cu system of the following chemical composition, wt.%:

Zinc 8.0-9.0 Magnesium 2.3-3.0 Copper 2.0-2.6 Zirconium 0.1-0.2 Iron, no more 0.4 Silicon, no more 0.3 Aluminum Rest

(see Industrial aluminum alloys: Ref. ed. / Alieva S.G., Altman MB, Ambartsumyan S.M. et al. 2nd ed., revised and enlarged. - M.: Metallurgy. 1984 P. 124).

The disadvantage of this alloy is its low ductility and insufficiently high characteristics of specific strength in a heat-treated (hardened and artificially aged) state.

Known high-strength wrought alloy based on aluminum of the Al-Zn-Mg-Cu system, containing, wt.%:

Zinc 6.0-8.0 Magnesium 3.4-4.2 Copper 0.8-1.3 Scandium 0.07-0.15 Zirconium 0.08-0.12 Beryllium 0.0005-0.004 Cerium 0.01-0.15 Titanium 0.02-0.08 Silicon 0.01-0.15 Iron 0.01-0.15 Hydrogen 0.05-0.35 cm ³ / 100g metal Inevitable impurities from the group Mn, Cr, V, Mo, Li, Ag, K, Na, O in the total amount, not more than 0.10 Aluminum Rest,

subject to the ratio between the content of magnesium and zinc from 0.53 to 0.57 (see patent RU No. 2514748 C1, C22C 21/06 - prototype).

The disadvantage of the prototype alloy is the insufficiently high strength and specific strength characteristics in a heat-treated (hardened and artificially aged) state with a sufficiently high ductility in the longitudinal direction.

A high-strength wrought alloy based on aluminum of the Al-Zn-Mg-Cu system is proposed, containing zinc, magnesium, copper, scandium, zirconium, cerium, titanium, hydrogen and unavoidable impurities, the main of which are iron, silicon, manganese and chromium, which is additionally contains boron in the following ratio of components, wt.%:

Zinc 7.8-8.2 Magnesium 2.0-2.4 Copper 1.8-2.1 Scandium 0.1-0.17 Zirconium 0.1-0.14 Cerium 0.0005-0.001 Titanium 0.01-0.03 Boron 0.0005-0.001 Hydrogen 0.05-0.3 cm ³ / 100g metal Aluminum and inevitable impurities Rest,

including:

iron in quantity not more than 0.12 wt. % silicon in quantity not more than 0.11 wt. % manganese in quantity not more than 0.02 wt. % chrome in quantity not more than 0.02 wt. %

subject to the ratio between the content of magnesium and zinc from 0.25 to 0.3.

A product made of a high-strength wrought alloy based on aluminum of the Al-Zn-Mg-Cu system of the following chemical composition, wt. %:

Zinc 7.8-8.2 Magnesium 2.0-2.4 Copper 1.8-2.1 Scandium 0.1-0.17 Zirconium 0.1-0.14 Cerium 0.0005-0.001 Titanium 0.01-0.03 Boron 0.0005-0.001 Hydrogen 0.05-0.3 cm ³ / 100g metal Aluminum and inevitable impurities Rest,

including:

iron in quantity not more than 0.12 wt. % silicon in quantity not more than 0.11 wt. % manganese in quantity not more than 0.02 wt. % chrome in quantity not more than 0.02 wt. %

subject to the ratio between the content of magnesium and zinc from 0.25 to 0.3.

The proposed alloy and the product from it differ from the prototype in that the alloy additionally contains boron and the components are taken in the following ratio, wt.%:

Zinc 7.8-8.2 Magnesium 2.0-2.4 Copper 1.8-2.1 Scandium 0.1-0.17 Zirconium 0.1-0.14 Cerium 0.0005-0.001 Titanium 0.01-0.03 Boron 0.0005-0.001 Hydrogen 0.05-0.3 cm ³ / 100g metal Aluminum and inevitable impurities Rest,

including:

iron in quantity not more than 0.12 wt. % silicon in quantity not more than 0.11 wt. % manganese in quantity not more than 0.02 wt. % chrome in quantity not more than 0.02 wt. %

subject to the ratio between the content of magnesium and zinc from 0.25 to 0.3.

The difference of the proposed alloy is also a lower ratio of magnesium to zinc, equal to an average of 0.275, and also that iron and silicon are considered as inevitable impurities.

The technical result is an increase in strength characteristics and characteristics of the specific strength of the alloy and products from it in a heat-treated (hardened and artificially aged) state and, as a result, an increase in the weight yield of the finished structures.

With the proposed content and ratio of components in the proposed alloy, the main strengthening effect is achieved due to the formation of dispersed precipitates of the strengthening phases M [Mg (CuZn) ₂ ] and T (MgZnAlCu) with a high density of their distribution in heat treatment (quenching and subsequent artificial aging) the structure of the semi-finished product, while due to the limitation of the content of inevitable impurities of iron, silicon, manganese and chromium, the number of inclusions of insoluble phases inevitably formed during crystallization of the alloy decreases na Al (Cu, Fe, Mn, Cr), Al (Zn, Mg, Cu, Fe) and Mg ₂ Si, respectively, increases the proportion of the main alloying components - zinc, magnesium and copper involved in alloy hardening during the heat treatment, which increases strength of the alloy and the product made from it. An additional hardening is made by the dispersed Al ₃ (Sc, Zr) phase, which is released during the inevitable technological heating of the ingot. The addition of cerium reduces the oxidizability of the alloy, which reduces the contamination of the alloy with oxide inclusions, thereby increasing the mechanical properties of the alloy and the product made from it. The addition of boron together with titanium grinds the grain in the ingot, thereby increasing the strength and plastic characteristics of the alloy and the product made from it. The proposed ratio between the content of magnesium and zinc provides a favorable combination of strength and plastic properties of semi-finished products and parts in a heat-treated state. The low and regulated on both sides of the hydrogen content provides high deformability of the alloy during hot processing, at the same time, the likelihood of hydrogen porosity decreases, which also positively affects the mechanical properties of the alloy and the product made from it.

Structural parts can be made from the proposed alloy for which it is important to reduce the mass of the structure with a corresponding increase in the mass of the payload. In the proposed product, the technical result is achieved in that a high-strength wrought alloy based on aluminum of the Al-Zn-Mg-Cu system of the following chemical composition, wt. %:

Zinc 7.8-8.2 Magnesium 2.0-2.4 Copper 1.8-2.1 Scandium 0.1-0.17 Zirconium 0.1-0.14 Cerium 0.0005-0.001 Titanium 0.01-0.03 Boron 0.0005-0.001 Hydrogen 0.05-0.3 cm ³ / 100g metal Aluminum and inevitable impurities Rest,

including:

iron in quantity not more than 0.12 wt. % silicon in quantity not more than 0.11 wt. % manganese in quantity not more than 0.02 wt. % chrome in quantity not more than 0.02 wt. %

subject to the ratio between the content of magnesium and zinc from 0.25 to 0.3.

Example

Received the proposed alloy from a mixture consisting of aluminum grade A85, zinc grade TSO, magnesium grade Mg95, copper grade Ml, cerium grade Cee-0, double ligatures aluminum-scandium, aluminum-zirconium, aluminum-titanium and triple ligatures aluminum-titanium- boron. The alloy was prepared in an electric resistance furnace, and ingots with a diameter of 178 mm were cast by semi-continuous casting.

The chemical composition of the alloy is shown in table 1.

The ingots were homogenized, cut into blanks, which were then turned to a diameter of 160 mm. Turned blanks were pressed at 400 ° C onto a bar with a diameter of 51 mm. The obtained rods were subjected to heat treatment (quenching and artificial aging) according to the regime: quenching at 473 ° C, holding at this temperature for 2 hours, cooling in water, aging at 125 ° C, 24 hours. The obtained rods in heat treated (quenched and artificially aged) state was subjected to tests with determination of density and mechanical properties. The mechanical properties (tensile strength σ _B , yield strength σ _0.2 , elongation δ) were determined during tensile testing at room temperature on standard tensile specimens cut in the longitudinal direction. The characteristics of specific strength (σ _Wood . And σ _0,2ud. ) _Were determined as the ratio of σ _B and σ _0,2 to density. The density and mechanical properties of the rods made of the prototype alloy made in the same way, the chemical composition of which are shown in table 1, were also determined.

The test results are shown in table 2.

As can be seen from table 2, the proposed alloy has, in comparison with the prototype, higher strength characteristics and specific strength characteristics. The use of the proposed alloy as a structural material will allow a 5-7% reduction in the mass of the structure with a corresponding increase in the mass of the payload and an increase in the characteristics of the weight return, which is fundamentally important for highly loaded structures of single use.

Claims (10)

1. High-strength wrought alloy based on aluminum of the Al-Zn-Mg-Cu system containing zinc, magnesium, copper, scandium, zirconium, cerium, titanium, hydrogen, aluminum and inevitable impurities, the main ones are iron, silicon, manganese and chromium , characterized in that it further comprises boron in the following ratio of components, wt. %: zinc 7.8-8.2 magnesium 2.0-2.4 copper 1.8-2.1 scandium 0.1-0.17 zirconium 0.1-0.14 cerium 0.0005-0.001 titanium 0.01-0.03 boron 0.0005-0.001 aluminum and unavoidable impurities rest,  including: iron no more than 0.12 silicon no more than 0.11 manganese no more than 0,02 chromium not more than 0.02, with hydrogen in the alloy is contained in an amount of 0.05-0.3 cm ³ / 100g metal, magnesium and zinc ratio is from 0.25 to 0.3. 2. A product from a high-strength wrought alloy based on aluminum of the Al-Zn-Mg-Cu system, characterized in that it is made of an alloy containing, by weight. %: zinc 7.8-8.2 magnesium 2.0-2.4 copper 1.8-2.1 scandium 0.1-0.17 zirconium 0.1-0.14 cerium 0.0005-0.001 titanium 0.01-0.03 boron 0.0005-0.001 aluminum and unavoidable impurities rest, including: iron no more than 0.12 silicon no more than 0.11 manganese no more than 0,02 chromium not more than 0.02, with hydrogen in the alloy is contained in an amount of 0.05-0.3 cm ³ / 100g metal, magnesium and zinc ratio is from 0.25 to 0.3.