DE1066030B - - Google Patents

Description

The invention relates to a method for the heat treatment of magnesium alloys with 5 to 7%. Zinc, 0.2 to 1% rare earth metals and 0.3 to 0.7% manganese with aluminum less than 0.1%, in which the alloys are solution annealed at a temperature a little below the solidus and at be cured at elevated temperature.

Magnesium-based alloys have become known through British patent specification 532 143, which 0.1 to 2% cerium, 1.1 to 12%. Zinc without or with 0.3 to 0.8% manganese, less than 1% aluminum and at least Contains 0.05% iron. These alloys, despite their excellent mechanical properties Properties have not been used in practice so far, since they tend to show the tendency when subjected to heat treatment

To enlarge the grain with the consequent reduction of the mechanical properties. A heat treatment of these alloys shows the tendency to distortion of the molding, which is the application of expensive chucks.

It has also been proposed in British Patent 693,478 to use these alloys also to incorporate beryllium by way of an aluminum beryllium master alloy, with the result, that the alloy contains up to 3% aluminum. It was found that despite the presence of the aluminum the aforementioned disadvantageous properties of these alloys are even more present.

In contrast, the method according to the invention of the type mentioned at the outset is characterized in that that the solution heat treatment by slowly increasing the temperature of 400 ° C gradually per half Hour by about 5 ° C to 445 to 465 ° C.

Compared to the prior art, it is in the present The context is initially new, gradually, i.e. gradually heated to a certain temperature. The alloy according to the invention is of a particular type. The known phenomenon that a Coarsening of the grain occurs during prolonged heating and at higher temperatures, does not teach us that a certain alloy, such as that underlying the invention, to a high temperature can heat without the disadvantage of coarsening the grain.

According to the teaching of the invention, not only is the maximum solution annealing temperature reduced, rather, it has been shown in the case of the alloys on which the invention is based that a Sufficient solution can only be brought about at a temperature which is close to the liquefaction point the alloy lies. However, when heated immediately to this temperature, it often occurs Grain growth associated with a corresponding reduction in mechanical properties.

Heat treatment method
of magnesium alloys

Applicant:

Magnesium Elektron Limited,

Clifton Junction, Manchester

(Great Britain)

Representative: Dipl.-Ing. F. Weickmann

and Dr.-Ing. A. Weickmann, patent attorneys,

Munich 2, Brunnstr. 8/9

Claimed priority:
Great Britain 11 June 1954

James Henry Thomas Petch,

Clifton Junction, Manchester (UK),

has been named as the inventor

For an alloy with 4% zinc, as after British Patent 532143, is the liquefaction point about 520 ° C. For a similar alloy with 6% zinc, the liquefaction point is 480 ° C, and consequently, the solution treatment temperature of the latter alloy is lower than that of the former Alloy. That is why, not grain growth prevention, is why according to the invention the solution heat treatment is limited to 465 ° C. So you simply cannot speak of a decrease in temperature. However, the alloy immediately goes up to 445 When heated to 465 ° C, as mentioned, grain growth often occurs.

The invention thus provides the teaching of how to use the alloys on which the invention is based can prevent grain growth and thus gain excellent mechanical properties. It will a solution treatment was first carried out by heating at a temperature which is significant is below the melting point. Stress relief can be achieved here without recrystallization and grain growth enter. The temperature is then slowly increased and the progressive stress relief allows a gradually higher temperature to be used without a grain enlargement until a temperature close to the melting point is reached is brought about.

909 629/260

Claims (1)

3 4 The molding consisting of the alloy can. very brief solution treatment is present, which at that after a temperature of at least predominantly in relatively low 445 ° C for a short time at a temperature between temperature ranges. 445 and 465 ° C are maintained. Appropriately, the alloy can be produced by Zu a temperature of 460 ° C is not exceeded. The 5 aggregates of magnesium, zinc, metals of the Precipitation heat treatment is 12 to 50 hours of rare earth and manganese. The latter is under carried out at a temperature of 130 to 200 ° C. Mediation of a manganese-based alloy electron It will be advisable to add the molding to AM 503 at the end with stirring. to cool the solution heat treatment. This cool- The zinc is in the form of a master alloy treatment precedes precipitation treatment, of course. io corresponding to British patent application 9 652/53 To carry out the heat treatment served before. The master alloy consists of raw zinc with about an alloy of about the following composition - 95% zinc and 5% iron, practically without aluminum, composition: silicon or content of other harmful impurities , cleanings. The manganese can be in the form of manganese f "* ···; ■■ · ■ ·, 5 to 7 / o _{chloride are added} . Metals of the rare Earth 0.2 to 1% Manganese 0.3 to 0.7% Patent claims: Aluminum less than 0.1% preferred _L Process for the heat treatment of magnetic "■, less than 0.03% ^ _siumleg i _ei -ungen with 5 to 7% zinc, and 0.2 to ■ % ^ls .f ^{n U} ' ^{U1 b} ! ^{s U} '.! / °. 1% rare earth metals and 0.3 to 0.7% ^{Tellurium from} _R ° ^b .l ^s 0> ϊ ^{/ o} ' ² ^ Manganese with aluminum less than 0.1%, at _> ... ^{maBlg U} ', ^b ' ^{s U> U5} £ ... which the alloys at a temperature little Beryllium ^ ίΛηϊο? solution annealed below the solidus and _Λ,. Ζ, ^{011 U) UUU1 bls Ölüb / 0} 2 ₅ higher temperature are hardened, thereby Magnesium residue characterized by the solution heat treatment A molding is used for the heat treatment, slowly increasing the temperature from 400 ° C which 0.7% rare earth metal, 6% zinc, gradually increasing every half hour by about 5 ° C Contains 0.5% manganese and 0.05% iron. This takes place between 445 and 465 ° C. The molding is initially heated to 400 ° C. The process according to claim 1, characterized in temperature is drawn every half hour by 5 ° C to 460 ° C that the alloy is increased after the heat, which is a total solution treatment of at least 445 ° C and before the treatment 6V2 hours. The briquettes in the form of precipitating heat treatment of a water cooling test rod, subject to British Standards. Specification..1101, Section One, Clause 9.2, are 35 3. Method according to claims 1 and 2, thereby then water-cooled and characterized at a temperature of that the temperature initially per 150 ° C. 50 hours of precipitation treatment. half an hour is increased by 5 ° C until a temperature subject. The mechanical properties are temperature of at least 445 ° C, the alloy the following: '· tion then cools and then the η ι n; Ci r λ η η j. -1,9-40 subjected to precipitation heat treated which 0.1% yield stress of 12.21 per inch ² *. , ^& . _A , ",. _T. ^& ._ ,. -A _0x , highest tensile stress .... 18.2 t per inch * · ^da """5f f ^ rA r ^ f ^ ™? ^{2 to 5} ° ^hours Elongation.pio 2.5? M. ...... .4.5 held at 130 Ims 200 ° C w.rd. .. ■ This result is surprising for this type of publications under consideration: of alloys, taking into account that a 45. British Patent No. 532 143. 909 629/260 9. 59