US2659131A

US2659131A - Composite alloy

Info

Publication number: US2659131A
Application number: US179774A
Authority: US
Inventors: Thomas E Leontis; Robert S Busk
Original assignee: Dow Chemical Co
Current assignee: Dow Chemical Co
Priority date: 1950-08-16
Filing date: 1950-08-16
Publication date: 1953-11-17
Anticipated expiration: 1970-11-17

Description

NOV. 17, 1953 T. E. LEoNTis ET AL 2,659,131

COMPOSITE ALLOY Filed Aug. 16, 1950 III IN V EN TORS. T homas Leon/1'8 BY Rober/ S. Busk A T7'ORNE Y3 Patented Nov. 17, 1953 UNlTED STATES rear ,oFricE COMPOSITE ALLOY' ware Application August 16, 1950, Serial No. 179,774

Claims. 1

The invention relates to a composite metal body of which magnesium is the predominant constituent. It more particularly concerns an improved composite magnesium-base alloy body comprising magnesium alloyed with zirconium.

Zirconium alloys with magnesium, under conventional alloying conditions, to a maximum extent of about 0.8 per cent. Among the advantages of alloying zirconium with magnesium are that a strong fine grained alloy is obtained. It is also possible to improve the binary magnesiumbase zirconium alloy by alloying various magnesium-soluble metals therewith, such as calcium. cerium (mischmetal), silver and zinc. In contrast, attempts to alloy the magnesium-soluble metal aluminum with the zirconium-containing magnesium-base alloys have not been successful because the aluminum and the zirconium react together to form an insoluble compound which settles out of the alloy. Insofar as we are aware, it is not possible with existing alloying methods to form magnesium-base alloys containing significant amounts of both aluminum and zirconium. The term magnesium-base alloy used herein means a magnesium alloy containing at least 80 per cent magnesium by weight.

We have now discovered that the foregoing difficulties of forming magnesium-base alloys containing both aluminum and zirconium in substantial amount are overcome by extruding at elevated temperature a zirconium-containing magnesium-base alloy in particulate form in admixture with the aluminum-containing metal constituent in particulate form. The resulting extrusion is a composite alloy body having enhanced tensile strength and other desirable properties. In addition, other metallic constituents capable of modifying the properties of the composite alloy may be included in its composition.

The invention then consists of the improved magnesium-base aluminum and zirconium-containing composite alloy, and method of making the same, hereinafter fully described and particu larly pointed out in the claims, the following description setting forth several modes of practicing the invention.

In carrying out the invention, various zirconium-containing magnesium-base alloys in particulate form may be used having an alloyed zirconium content of 0.1 to 0.8 per cent. A preferable proportion of zirconium is between about 0.2 and 0.6 per cent, 0.3 per cent being generally satisfactory. Although the binary magnesiumbase alloy of magnesium and zirconium may be used as the zirconium-containing magnesiumbase alloy in the mixture of particulate metals to be extruded, generally higher strengths are obtained by including at least another metal, which is soluble in magnesium in the presence-of zirconium, as an alloyed constituent of the magnesium-base zirconium-containing alloy, as for example, cerium (e. g. mischmetal) in amount up to about 2 per cent, zinc up to about 8 per cent, silver up to about 6-per cent, or calcium up to 1 per cent. Combinations of two or more of these metals may be-used'in the alloy.

The zirconium-containing magnesium-base alloy may be reduced to particulate form for use in the invention in any convenient manner as by grinding or atomizing. The atomized form is preferred and may be produced by forming a melt of the alloy and atomizing it by impinging a jet of a cool gas, e. g. natural gas, against a thin falling stream of the molten alloy. The atomized alloy consists of a mixture of various sized fine spherical rapidly solidified particles of the alloy, the particles having a very fine structure. It is desirable to screen out particles coarser than those passing about a 10 to 20 mesh standard sieve.

The aluminum constituent of the mixture of the particulate metals to be extruded, according to the invention, may be either elementary aluminum or aluminum alloyed with a magnesium-a1- loyable metal. It is preferable to employ the aluminum as an alloy with magnesium, as in magnesium-base alloys containing aluminum. For example, the binary magnesium-base alloy of magnesium and aluminum, and the ternary magnesium-base alloys of magnesium, aluminum, and zinc, such as the conventional magnesiumbase aluminumand zinc-containing structural alloys, which may also contain a small amount of manganese, may be used in particulate form to supply the aluminum constituent of the mixture of the particulated metals to be extruded.

The aluminum-containing constituent of the mixture of particulate metals to be extruded is reduced to particulate form in any suitable Way, such as any of those mentioned in connection with the magnesium-base magnesium-zirconium alloy. In the instances in which the aluminum constituent is alloyed with magnesium, as aforementioned, it is preferable to reduce the alloy to particulate form by atomization as already described. The particle size of the bulk of the aluminum-containing constituent is made preferably smaller than that of the bulk of the zircomum-containing constituent in order to obtain good distribution of the aluminum-containing constituent throughout the extrusion charge. Other metallic constituents, if any, in the extrusion charge may be reduced to particulate form in any appropriate manner.

Before extrusion, the metals in the particulate form described are mixed together to form a uniform mixture of the metal particles comprising the extrusion charge. Substantially all the particles should be capable of passing about a to 20 mesh standard sieve. The relative amounts of the particulated zirconium-containing magnesium-base alloy and the particulated aluminum constituent are adjusted so that there is a minimum content of about 0.5 per cent to a maximum of about 6 per cent of the aluminum tional particulated magnesium-base alloy not containing either aluminum or zirconium (this alloy may also contain Ca or Zn). The zinc and calcium may be used as just indicated or as particulated unalloyed metal introduced op-' tionally into the extrusion charge. Cadmium, lead, and tin likewise may be used in particulated unalloyed form to modify the character of the composite alloy formed. The metals: Mn, Cd, Pb, Sn, and Zn when used in unalloyed form may be added in total amount up to about 2 per cent of the weight of the charge. The amount of magnesium in the charge is thus dependent upon the amount of the non-magnesium constituents introduced into the charge, and, exclusive of the zirconium and aluminum. which together constitute at most about 6.1 per cent of the charge, the aforementioned nonmagnesium constituents (both alloyed and unalloyed) may amount to as much as about 18 percent of the Weight of the charge. The magnesium content, determined by difizerence, may range from a minimum of about 82 per cent to a maximum of about 99.4 per cent. The following chart summarizes the foregoing and shows the sources of the zirconium, aluminum, and other magnesium-soluble metal, if any, in the extrusion charge, or mixture of particulate metal, to be extruded to form the composite alloy.

Chart of extrusion charge components of particulated metals Sources of zirconium in charge-Zirco ium-eontai ing ma esium-base alloy (Zr content 0.1 to 0.8%).

Sources of aluminum in charge- Aluminumcontalning metal Sources of optional modifying components in arge Un alloyed metal Alloycd metal (1) Mam esium -base binary magnesiumzirconium alloy.

(2) Magnesi m -base magnesium-zircori n allo co" taming up to 2% of Ce, up to 6% of Ag, up to 8% of Zn, up to 1% of Ca.

Amount used being sufificient to introduce at least 0.095% of Zr by weight into the charge.

charge.

(1) Unalloye'l alum inum.

(2) Bi ary ma nzeslmn-aluminum alloys.

(3) Ma nesium-base alloys contai ir g up to 12% of aluminum and up to 5% ofzinc.

(4) Ma nesium-base alloys containing up to 12% of aluminum and up to 2% of mananesc.

(5) Ma nesium-base alloys containing up to 12% of aluminum up to 5% ofzinc and up up to 2% of manganese.

Amount used being suflicient to introduce at least 0.5 to 6% by weight of aluminum into the (l) Manganese. (1) Mn as magnesium-base (2) Cadmium. magnesium-manga- (3) Lead. nesc alloy containing (4) Tin. 0.1 to 2.5% oi Mn. (5) Zinc. (2) Ditto and co tairing up to 0.5% of On One or more of andup to3%ofZn.

above, if used, in total amount up to 2% of charge.

Amount used, if any,

being sufficient to introduce up to 1% of manganese by weight into the charge.

constituent (either alloyed with magnesium or as elementary aluminum) in the mixture, and a zirconium content in the mixture of at least about 0.095 per cent. The major portion by weight of the mixture of particulated metals to be extruded is the magnesium of the alloyed magnesium therein. The minor portion comprises the non-magnesium metals, viz. the constituents: aluminum and zirconium as well as any additional magnesium-soluble metals which may be used in the charge, e. g. cerium, silver, zinc, calcium, cadmium, lead, tin and manganese. Of these additional metals, the Ce, Ag, Zn and Ca may be introduced into the mixture as alloyed constituents of the particulated magnesium-base zirconium alloy, as aforesaid. The manganese may be introduced into the charge as particulated elementary manganese or it may be alloyed with the magnesium with which the aluminum constituent may be alloyed, or it may be introduced as an alloyed constituent of an addi- The mixture of the particulated metals is charged into the heated container of a ram extruder, having a suitable size container and die opening, and subjected to extrusion pressure to cause the particulate metals to be heated and extruded together through the die-opening.

As to the extrusion conditions, the temperature of the particulated metal mixture in the container may be the same as that conventionally employed for extruding solid ingots of the known magnesium-base aluminum-containing alloys, e. g. from about 500 to 900 F., the usual temperature being about 650 to 850 F. The ratio of the cross-sectional area of the extrusion container to that of the die-opening has a material effect on the mechanical properties of the extrusion product obtained. A desirable ratio is at least about 30 to 1, although ratios as high shape of the die-opening. gIn anycasepthe speed is to be held down to that at-which the extrusion produced is free from hot shortness. A safe lextrusio-n speed may be ascertained by visual examination of the product as i-t extrudes, 'l heshot shortness bein evident as cracks inthe extruded product and sharply reduced strength.

The extruded product obtained is a composite metal body or alloy having the same. compactness and integrity as the usual magnesium-base alloy extrusions made from a solid mass, such as an ingot of a magnesium-base alloy, but uniquely differs from it in metallographicstructure.

each of the particulated forms of .thseimetals in the ext usio charge the ar fl s havin b com elongated with the longaxis parallel to that of the extrusion. The elongated particles arewelded one to the other without voids. There is difiusion of some of the aluminum constituent of the aluminum-containing particles into the particles of the zirconiumecont-aining magnesium-base alloy and precipitation thereby of zirconium therein; and there is same diffusion o magnesium from the zirconium-containing magnesium-base alloy particles into the aluminum or other magnesium-soluble metal constituent, if present, forming composite alloy. The composite alloy extrusion obtained may be subjected to the sa ty s f metal wcrki-n aoperatien a e ploy d with conve tio al :ma h sium base QHQYS, .e. a r l n w d g, f cin chemi al fin sh n electroplating, etc. The mechanical prcpertiescf t e c mpo t ey ene ally the c nvent o l ma sium-base con i n alloys and he amsunt sf may e t least a much mar s al oyed with m esium slam: n s e c hc usish cf aluminum or t r ma n s m-sums m al.

The invention may be :further i -l shnated and explained n commence w th the accompanyin drawing in which:

F g. 1 shows a schematic sec ional elevation ,o extrusion ar tu shi blerisr in practicing the invention;

Fig. 2 is a simi ar y-i to Fi 1 she-w ne a modification of the apparatus and 'Fig. 3 is a similar view to Fig, .11 showing another modification of the apparatus,

As shown, the apparatus comprises, in :itsithree forms, an extrusion container 1 adapted tocon- The structure is essentially multimeta'llic,, b in comp s c he innu e ble ;carticles.c.

.nne'a charge 12 of the mixture-of metal particles to-be termed intoathecomposite alloy. The contamer is provided with a heating element ;3. :In Fig. 1, one end :of the container l is closed by thedie plate A inwhich is provided the die-opening :5. In this formcf the apparatus, the char 2 is caused to be compacted inthe container and extruded through the die-opening 5 by application of pressure by means of the dummy block 6 forced into the bore I of the container by the ram 8 to form the extrusion 9 of composite alloy.

In the form of the apparatus shown in Fig. 2, the .cpntainer I is closed at one end by the plate J9. other .end of the container receives the i die 1h och I] carried by the hollow ram I2 which forces the die-hlock into the container causing the charge2 to be compacted and to extrude through die opening 13 to form the composite alloy extrusion M which extends into bore l5 of the hollow ram 12.

In the modification of Fig. 3, the container is closed at one end with a plate I6. The charge ,2 is extruded ,as a tubular composite alloy extrusion I! through the annulus l8 around the die block l9 while it is forced into the container by the ram 20.

The forms of the apparatus shown are conventional.

By putting a charge of the mixture of the metals involved according to the invention under pressure while at heat, as with t ap u shown, the mixture of metal particles is compacted but not subjected to further mixing beiore extrusion. The metals originally in the charge as individual metal particles become welded together without voids into an integral compacted mass of elongated particles substantially without mixing. The particles in the compacted mass do not lose their original distinctive com-position except at the surfaces .of the union :of the different kinds of particles which "become extended and lengthened during ex- -itrusion, giving the particles their elongated form.

Atthesesurfaces during extrusion, some difiusion takes place of metal of one kind of particle to an adjacent particle of different metal, as already mentioned, forming composite alloy.

Examples, set forth in Table I, are illustrative of the invention as embodied in the coextrusion pf particulated binary magnesium-base zirccniumal qyand pa ti ulated elementary alumimixedtogether to form the extrus chargelifl lble I i ;Me ehanical properties of extrusion in @omposltion oiextrusion charge ofpar- L000 3 i tilculated A mixed with particulated l a umlmim I i ,Y As exm H. I.+

( {Ended Agfid I ,H. l Aged 2 Weight 3 Weight; E perfkent AnalysispiA ipe xent TYb TS TYS TS 'IYS TS 'IYS TS E i 1 I E f f V w... ..l.. 4 I, 0.38%Zl1, he]. .1 2 ,38 3.5 1 43 31 40 36 42 d ().,5 33 40 39 v 44' {ll 45 42 45 d0- .GJO l 40 42 v .41 41 l 49 52 5 '49 51 d0 None 26 36. 29 .37 l 28 37. .28 .36 IMg 0.5 '26 36 '32 '37 25 32 25 33 d0l 6. 0 24 33 24 311 29 39 I .25 34 do None 21 36 27 361 20 39 22, so

H. Tel-Aged =heated TS.=J.tensile yield vstrength, the stress at then odulusllne. 'TS=tensile strength.

llhour at 750" F. followed by heating for 16 hoursat 350 F.

whichithe stress-strain curve dc'viates 0.2 percent from Referring to Table I, the various compositions shown of the particulated metal or metals were extruded in the form of wire 0.086 inch in diameter from a heated extrusion container 0.5 inch in diameter at the rate of about 1 to 2 feet per minute using an apparatus similar to that of alloyed with magnesium in the proportions corresponding to the eutectic compositions, in the binary magnesium-aluminum alloy system, viz. 31.6 percent Al, balance Mg, and 66.5 per cent Al, balance Mg. In making these extrusions, the same apparatus was used as for the extrusions of Table I, the reduction in area being 34:1.

Fig. 1. The reduction in area was 34 to 1. The

Table II Composition of extrusion charge of par- Mechanical properties 1 in 1000's p. s. 1. ticulated A mixed with particulated am 16 B (Mg-Al eutectic) I Extru- I sion As ex- A ed H T H. 'I. k A temp., truded g Aged Weight Weight r.

percent Analysis of A percent A B TYS TS 'IYS TS TYS TS TYS TS 97 0.54% Zr, bal. Mg. 3 3 800 38 37 41 39 43 40 43 94 l 1 6 800 37 41 39 44 38 46 37 46 91 2 9 S00 36 43 39 40 47 42 47 88 2 12 800 41 42 44 46 4G 47 43 48 82 -do 2 18 800 40 47 41 44 43 50 43 47 100 .do None 800 28 36 33 41 28 38 28 37 9 91 0.33% Zr, bal. Mg... 3 9 750 39 43 45 48 46 48 45 48 Blank 6. 100 do NOIle 670 24 35 25 35 25 36 27 34 1 See footnotes of Table I. 2 Analysis 31.03% Al, balance Mg. 3 Analysis 66.5% A1, balance Mg.

container temperature was about 800 F. and the die about 710 F. The particles of the magnesium-base magnesium-zirconium alloy were of atomized form passing a 20 mesh sieve and remaining on a 200 mesh sieve. The particulated aluminum was finer in particle size than the particulated magnesium-base alloys, about 82 per cent passing through 100 mesh sieve and about 58 per cent passing through a 200 mesh sieve. The particulated elementary magnesium included in blanks 2 to 5 for comparison was in the atomized form and similar in sieve analysis to that of the binary magnesium-zirconium alloy used.

The extrusion of Examples 1, 2 and 3 contain both aluminum and zirconium in amounts far beyond those alloyable with magnesium in conventional manner. Metallographic examination shows that each extrusion is essentially a unique multimetallic body of elongated particles of the binary magnesium-base magnesium-zirconium alloy and elongated aluminum particles, the two kinds of particles being interspersed and welded together into a composite alloy without voidsv The elongated particles in the extrusion are oriented with their long axes parallel to the axis of the extrusion. In addition, some diffusion occurs of aluminum into the surface of the elongated magnesium-zirconium alloy particles and of the magnesium into the surface of the elongated aluminum particles; and there is the formation and precipitation of some zirconiumaluminum compound in the binary magnesiumzirconium alloy particles near the boundaries demarking the two kinds of metal particles of the composite alloy.

Examples, set forth in Table II, are illustrative of the invention as embodied in the coextrusion of a particulated binary magnesium-zirconium alloy and a particulated alloyed formof aluminum. In these examples, the aluminum is By employing the aluminum constituent of the extrusion charge alloyed with a considerable proportion of magnesium, as in the foregoing examples (4 to 9, inclusive), a better distribution is had of the aluminum constituent throughout the mixture of particulate metal to be extruded, and the surface of the composite alloy extrusion is generally smoother than similar composite alloys made with unalloyed aluminum. The proportion of aluminum in the extrusion charges of Examples 4 to 8, inclusive, is approximately 1 2, '3, 4, and 6 per cent, respectively, the zirconium content is approximately 0.52%, 0.51%, 0.49%, 0.47%, and 0.44%, respectively, and the balance is magnesium. The proportion of aluminum in the extrusion charge of Example 9 is about 6 per cent and that of the zirconium about 0.3 per cent, the balance is magnesium. The metallographic structure of the extrusions of Examples 4 to 9 is generally similar to that of the extrusions of Examples 1, 2 and 3.

The inclusion of one or. more magnesiumsoluble metals, e. g. cerium (mischmetal), zinc, calcium, silver as an alloyed constituent of the zirconium containing magnesium base alloy "member ofthe'extrusion charge, as aforementioned, is generally advantageous. Examples are set forth in Tables III and IV which are illustrative of the use of cerium in this embodiment of the invention, additional examples also appear .in Table VII below (in the examples of Table IV, the aluminum constituent in the extrusion charge is the alloyed aluminum constituent of a conventional magnesium-base alloy containing aluminum, zinc, and manganese); the examples in Table V are illustrative of the use of zinc, in this embodiment of the invention; the examples in Table VI are illustrative of the use of two mag- 70 nesium-soluble metals, calcium and zinc, in this yembodimentotthe invention (further examples of this use of calcium and zinc also appear in Table VII below); and the examples in Table YVIII are illustrative of the use of silver in this 75 embodiment of the invention.

Table VI Composition of extrusion charge of particulated A mixed with particulated B Extwgion ffl fi teutsile y i ia Blank No. Wei ht Weight percegt A Analysis of A percent B Analysis of B 1000 s p. s. 1.

99. 5 0.44% Zr, 1.80% Zn, 0.43% Ga, bal. Mg 0. 5 39 do 1.0 44 3. 0 44 6.0 46 None 6. 0 39 9. 0 44 12.0 18. 0 48 1. 0 41 3.0 41 None .35 6.0 40 9. 0 43 12.0 46 18.0 0.5 34 1. 0 34 3.0 38 None 24 6. 0 35 9.0 37 18.0 40

1 Extrusion heat treated 1 hour at 750 F.; extrusion conditions: F.; extrusion diameter 0.091 inch; reduction in Extrusion temperature area 30:1.

extrusion charge, it is advantageous to employ as the particulated magnesium-base alloy, one containing manganese, examples of which appear If desired, there may be included in the mix: ture of the particulated zirconium-containing magnesium-base alloy and the particulated aluminum-containing constituent to be extruded, another particulated magnesium-base alloy. In such combinations of particulated metal of the herein. The useof alloyed manganese in this embodiment of the invention is illustrated in the examples of Table VII.

Table VII Composition of extrusion charge of particulated metals A, B, and C Extrusion tensile Redu c- Extrusion Exam 1e yield No. Weight Weight Weight strength 1 11148111510118,

percent Analysis of A percent Analysis of B percent Analysis of 0 1000s m area me 195 A B C p. s. i.

48. 5 0.514% Zr, 2.12% Zn, bal. 3 100% A1.-- 48. 5 1.76% M11, bal. Mg 47 30:1 0.094 Wire.

g. 47. 0 0.354% Zr, 0.22% Ce, bal. 6 -d0 47. 0 1.37% Mn, bal. Mg 47 31:1 0.090 wire.

g. 41. o 1o 18 31.6% A1, 41.0 -.do 46 31:1 0.091 wire.

bai. Mg. 47. 0 0.2 1 Zr, 1.14% Zn, bal. 6 100% A1..... 47.0 do 47 27:1 0.097 Wire.

g. 41. 0 do 18 I 6;% AI, 41.0 do 45 27=1 Do.

7 a g. 47. 0 0.551% Zr, 2.12% Zn, bal. 6 100% Al.. 47.0 1.76% Mn, bal. Mg 49 27:1 Do.

g. 47.0 0.431% Zr, 7.67% Zn, bal. 6 do 47. 0 1.37% Mn, bal. Mg 37 27:1 Do.

g. 44. 0 do 12 31 6i% A1, 44. 0 do 42 27:1 Do.

a g. 47. 0 0.44% Zr, 1.80% Zn, 6 100% AL--- 47. 0 .....d0 49 30:1 0.092 wire.

0.43% Ga, bal. Mg. 47. 0 0.61% Zr, 3 81% Zn, 6 ..do 47.0 1.37% M11 45 30:1 Do.

0.28% Ga, bal. Mg. 47. 0 0.47% Zr, 5.41% Zn, 6 .do 47. 0 1.37% Mn, bal. Mg 45 301 Do,

0.26% Ga, bal. Mg. 44.0 0.26% Zr, bal. Mg 12 31.6;MA1, 44.0 1.78% Mn, bal. Mg 39 64:1 0.375 2 3 oa g. 44. 0 0.48% Zr, 0.17% Ce, be]. 12 ..-d0 44.0 1 \I/1n, 0.17% Ca, 38 150:1 %x%strip.

Q a g. 48.5 0.23% Zr, 0.13% Ce, 3 A1 48. 5 1.88% 1\1/}/In, 0.06% Ga, 39 :1 D05 g. a g. 48. 5 0. Zr, 2.53% Zn, be]. 3 do 48.5 1.78% Mn, bal. Mg 43 150:1 Do.

g. 44. 0 0.66% Zr, 5.47% Zn, bal. 12 31B6{%MA1, 44.0 1.71% M11, bal. IVIg 40 150:1 D05 E- a g. 44. 0 0.444% Zr, 7.67% Zn, bal. 12 (10 44. 0 1.8g? l\."L/}11, 0.06% Ga, 35 150:1 Do.

a g. 43. 5 0.54% Zr, 3.85% Zn, 3 100% A1.-- 48. 5 -do 43 15011 DOA 0.29% Ga, bal. Mg. 44. 0 do 12 31.6% A1, 44.0 do 42 150:1 D03 bal. Mg. 44.0 0.69% Zr, 5.41% Zn, 44. 0 44 150:1 Do.a

0.44% Ga, bal. Mg. 68. 25 0.57% Zr, bal. Mg 22. 75 1.82% Mn, bal. Mg 39 150:1 Do.

1 Heat treated 1 hour at 750 F. I Extruded at 600 F.

3 Extruded at 650 F.

Wire extruded at 700 F.

In Examples 77 to 88, inclusive,and 91, 92, 97 of Table VII the manganese-containing magnesium-base alloy ingredient of the mixture of particulated metals constituting the extrusion charge are conventional binary magnesium-base magnesium- -manganese alloys. In Examples 89, 90, 93, 94, 95, and 96 of the table, a small amount of calcium is included in the binary magnesiummanganese alloys. A particular advantage of including in the extrusion charge the manganese-containing binary magnesium-base alloy, with or without calcium is a reduction in sensitivity of the composite alloy to stress corrosion.

1 41 the zirconium-containing magnesium-base alloy also contains zinc.

7. The method according to claim 1 in which the zirconium-containing magnesium-base alloy also contains calcium.

8. The method according to claim 1 in which the zirconium-containing magnesium-base alloy also contains silver.

9. The method of making a solid composite article comprising a magnesium-base magnesium-zirconium alloy which comprises forming a mixture of a particulated zirconium-containing magnesium-base alloy, a particulated aluminum- Table VIII Composition of g f ig g g particulated Mechanical properties in 1000's p. s. 1. Elample H. '1. 1 hr. H. '1. 16 hrs. 1, Weight Weight ASX 750 F. 750 F.

perient Analysis of A perlgent TYS CYS TS TYS CYS TS TYS CYS TS 98 97 0.48% Z1, 2.75% Ag, bal. Mg 3 36 35 43 43 37 49 44 36 49 99 94 d0 6 39 33 45 45 36 52 45 36 52 Blank 24 100 34 26 41 26 32 11 1.00.. 97 3 37 36 47 44 40 52 45 38 52 lol 94 6 37 37 48 46 40 53 47 40 53 Blank 10D 0 33 29 43 28 21 36 26 17 36 Extrusion temp. 650 F. Reduction in area 64:1. Speed 2 feet/min.

Anal sis of B=31.6% Al, Bal M 1 ASX=as extruded; H. T.= strength.

The extrusions set forth in the Tables II to VIII, inclusive, were made with apparatus similar to that of Fig. 1 and the composite alloys obtained had a metallographic structure similar to that of other examples.

In addition to the advantages already men tioned, it is manifest that the composite alloy of the invention may be held at elevated temperatures without loss of strength, thereby permitting hot working without loss of tensile strength.

We claim:

1. The method of making a solid composite article comprising a magnesium-base magnesium-zirconium alloy which comprises forming a mixture of a zirconium-containing magnesium-base alloy in particulate form and an aluminum-containing metal in particulate form, said mixture comprising at least 0.5 per cent of aluminum, at least 0.095 per cent of zirconium, the amount of the aluminum plus the zirconium not exceeding 6.1 per cent, and up to 18 per cent of non-magnesium metal exclusive of the said aluminum and zirconium, the balance of the mixture being magnesium, and die-expressing the mixture in solid condition at a temperature of at least 500 F.

2. The method according to claim 1 in which the aluminum-containing metal is a magnesium alloy containing at least 0.5 per cent of aluminum.

3. The method according to claim 1 in which the aluminum-containing metal is a magnesiumbase alloy containing at least 0.5 per cent of aluminum and zinc.

4. The method according to claim 1 in which the aluminum-containing metal is a magnesiumbase alloy containing zinc, at least 0.5 per cent of aluminum, and manganese.

5. The method according to claim 1 in which the zirconium-containing magnesium-base alloy also contains cerium.

6. The method according to claim 1 in which Size extrusion x section.

heat treated; TYS tensile yield strength; GYS compression yield strength; TS tensile containing magnesium-base alloy, and a particulated unalloyed magnesium-soluble metal selected from the group consisting of manganese, cadmium, lead, tin, zinc, said mixture comprising at least 0.5 per cent of aluminum, at least 0.095 per cent of zirconium, the amount of the aluminum plus the zirconium not exceeding 6.1 per cent, and up to 18 per cent of the said magnesium-soluble metal, the balance of the mixture being magnesium, and die-expressing the mixture in solid condition at a temperature of at least 500 F.

10. A composite metal body comprising at least two particulated metals, one of the metals consisting of a magnesium-base magnesium-zirconium alloy, the other comprising aluminum, the particles of each of the said two metals being elongated, oriented in the same direction, and welded together into an integral solid, said solid comprising by weight at least 0.5 per cent of aluminum, at least 0.095 per cent of zirconium, the amount of the aluminum plus the zirconium not exceeding 6.1 per cent, and up to 18 per cent of non-magnesium metal, exclusive of the aluminum and zirconium, the balance being magnesium.

THOMAS E. LEONTIS. ROBERT S. BUSK.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,913,133 Stout June 6, 1933 2,024,767 Jeffries et al Dec. 17, 1935 2,205,865 Schwarzkoff June 25, 1940 2,332,277 Stern Oct. 29, 1943 2,355,954 Cremer Aug. 15, 1944 (Other references on following page) Number 15 FOREIGN PATENTS Country Date Great Britain June 26, 1945 Great Britain July 27, 1945 Great Britain June 27, 1949 16 OTHER REFERENCES "Treatise on Powder Metallurgy, by Goetzel, vol. 2, pp. 500, 740, 741; 1950.

Symposium on Powder Metallurgy, Buffalo spring meeting, March 3, 1943, published by American Society for Testin Materials, Philadelphia, Pa., pages 42 and 43.

Claims

10. A COMPOSITE METAL BODY COMPRISING AT LEAST TWO PARTICULATED METALS, ONE OF THE METALS CONSISTING OF A MAGNESIUM-BASE MAGNESIUM-ZIRCONIUM ALLOY, THE OTHER COMPRISING ALUMINUM, THE PARTICLES OF EACH OF THE SAID TWO METALS BEING ALONGATED, ORIENTED IN THE SAME DIRECTION, AND WELDED TOGETHER INTO AN INTEGRAL SOLID, SAID SOLID COMPRISING BY WEIGHT AT LEAST 0.5 PER CENT OF ALUMINUM, AT LEAST 0.095 PER CENT OF ZIRCONIUM, THE AMOUNT OF THE ALUMINUM PLUS THE FIRCONIUM NOT EXCEEDING 6.1 PER CENT, AND UP TO 18 PER CENT OF NON-MAGNESIUM METAL, EXCLUSIVE OF THE ALUMINUM AND ZIRCONIUM, THE BALANCE BEING MAGNESIUM.