RU2370560C1 - PROCEDURE FOR PRODUCTION OF ALUMINIUM ADDITION ALLOY Al-Mg-Mn-Y FOR PRODUCTION OF ALUMINIUM ALLOYS - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: procedure of production of aluminium addition alloy Al-Mg-Mn-Y for production of aluminium alloys consists in preparing charge out of halogenides of alkali metals, manganese oxide and 2-3 wt % yttrium oxide, in reducing manganese oxide and yttrium oxide with aluminium alloy with 17-20 wt % of magnesium, heating to 950-1000°C and holding within 1-2 hours.

EFFECT: production of additional alloy facilitating production of aluminium alloy on base of aluminium with fine micro-structure and maximal effect of hardening.

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Description

The invention relates to the field of metallurgy of non-ferrous metals, in particular to methods for producing aluminum alloys with rare metals.

A known method of direct fusion of aluminum and rare metals in an argon atmosphere [Altman MB Metallurgy of cast aluminum alloys. - M.: Metallurgy, 1972. 153 p.]. The disadvantage of this method is

the use of relatively expensive starting materials in metal form, a large waste of rare metals during melting.

A known method of producing aluminum-manganese alloys [Napalkov VN, Makhov SV. Doping and modification of aluminum and magnesium. - M .: MISiS. 2002. S.200-201], including fusion in the crucible furnaces of the starting elements at 1000 ° C and refining at 850 ° C with manganese chloride, while the manganese fume is 5%.

Aluminum-manganese ligature is also obtained in aluminum electrolyzers by introducing manganese oxide or manganese metal into it [Ibid., P.202].

As a prototype, a method for producing complex rare metal alloys of the Al-Mn-Sc system [Naumkin V.P., Terekhova V.F., Savitsky E.M. // Izv. USSR Academy of Sciences. Metals 1965. No. 4, p.176-182]. The ligature is obtained by arc melting in an argon atmosphere at a temperature of 1800 ° C using pure aluminum, scandium metal powders and electrolytic manganese.

The disadvantage of this method is the need for preliminary production of powders of the initial alloying components of the mixture, which does not allow to reduce their cost and consumption and achieve a homogeneous distribution of fine-grained intermetallic compounds.

The technical result of the invention is to obtain a complex ligature, which allows you to synthesize aluminum alloys with a fine microstructure and maximum hardening effect, while saving alloying elements and enhances their positive effect.

The technical result is achieved by the fact that in the method of producing aluminum ligature Al-Mg-Mn-Y to obtain aluminum alloys, which consists in the preparation of a mixture of alkali metal halides and manganese oxide and its reduction by an alloy of aluminum with 17-20% magnesium, according to the invention previously the mixture is added 2-3 wt.% yttrium oxide, heated to 950-1000 ° C and hold for 1-2 hours.

The essence of the proposed method is as follows.

In most aluminum alloys, magnesium is the main constituent. Joint alloying of an aluminum alloy with manganese and yttrium strengthens the aluminum matrix due to the following: when alloying manganese alloys, a high rate of coarsening of Al ₆ Mn intermetallic compounds is observed upon heating. With the introduction of yttrium, secondary particles of the Al ₃ Y phase are formed, which coagulate at a much lower rate than Al ₆ Mn particles, ultimately they retain high dispersion and, accordingly, the ability to inhibit recrystallization and harden the aluminum matrix. In the reduction of manganese and yttrium oxides by an Al alloy with 17–20% Mg, the latter plays the role of a reducing agent, while aluminum plays the role of a collector. In this case, the process of reducing compounds of manganese and yttrium oxides proceeds actively and simultaneously.

It should be noted that precursors are formed in the halide melt - halide compounds of manganese and yttrium in the form of molten salts. During the subsequent reduction of such a melt, Al ₆ Mn and Al ₃ Y intermetallic compounds of a given composition are synthesized, which will ensure their positive effect on the structure and properties of the alloys and semi-finished products obtained subsequently. Thus, the use of Al-Mg-Mn-Y ligatures seems to be optimal for producing aluminum alloys. In this case, a relatively cheap crude yttrium concentrate with a reduced yttrium oxide content can be used.

The choice of parameters is due to the following.

The yttrium content in the melt below 2.0 wt.% Will not allow to obtain a master alloy of a given composition, and its technological (modifying) properties will be violated. If the yttrium content in the melt is more than 3 wt.%, This will lead to an over expenditure of the expensive component (yttrium) and the ligature becomes economically disadvantageous.

Heating the charge lower than 950 ° C does not allow to synthesize a homogeneous ligature, the recovery process is inhibited, and large intermetallic compounds are formed; at a synthesis temperature of more than 1000 ° C, loss of alloying components is possible.

When the melt is kept for less than 1 hour, the process of interaction of the starting reagents does not proceed completely and the losses of the alloying metal increase. If the exposure time is more than 2 hours, increased fumes of alloying components are possible.

Example. The laboratory setup consists of a shaft furnace, a sealed reactor, and a beaker. An aluminum alloy with 17-20 wt.% Magnesium is used as a reducing agent; the initial charge consists of sodium, potassium, aluminum, and manganese and yttrium oxides. The temperature of the process is 900-1050 ° C. At the end of the process produced exposure. The resulting products were cooled and analyzed for element content. The results are shown in the table.

The data obtained indicate the technical effect of the proposed method: the joint reduction of manganese and yttrium oxides can reduce the consumption of expensive powder components by 15%, increase the degree of extraction of alloying elements in the ligature, and ultimately improve the modifying joint action of alloying elements.

Claims (1)

A method of producing aluminum alloys Al-Mg-Mn-Y to obtain aluminum alloys, including the preparation of a mixture of alkali metal halides, manganese oxide and 2-3 wt.% Yttrium oxide, the reduction of manganese oxide and yttrium oxide with an aluminum alloy from 17-20 wt. % magnesium when heated to 950-1000 ° C and exposure for 1-2 hours