ri6170 indium effect onsi and ca solid soubility in mg

8/2/2019 RI6170 Indium effect onSi and Ca solid soubility in Mg

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DI ureau of mines 617011 report of investigations R ECE IVED. uREAU 0 M NEe

IIPOILANE. WAS"

EFFECT OF INDIUM ON THE SOLIDSOLUBILITY OF CALCIUMAND OF SILICON IN MAGNESIUMBy R. L. Crosby and K. A. Fowler

UNITED STATES DEPARTMENT OF THE INTERIORBUREAU OF MINES

1963


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EFFECT OF INDIUM ON THE SOLIDSOLUBILITY OF CALCIUMAND OF SILICON IN MAGNESIUM

By R. 1. Crosby and K. A. Fowler

report of investigations 6170

UNITED STATES DEPARTMENT OF THE INTERIORStewart L. U daH, SecretaryBUREAU OF MINES

Marling J. Ankeny, Director


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This publication has been cataloged as follows:

Crosby, Robert LEffect of indium on the solid solubility of calcium and of

silicon in magnesium, by R. L. Crosby and K. A. Fowler.[Washington) U.S. Dept. of the Interior, Bureau of Mines (1963)

11 p. illus., tables. 27 cm. (U. S. Bureau of Mines. Report ofinvestigations, 6170)

1. Indium. 2. Magnesium compounds. I. Fowler, K Ajoint author. II . Title.

TN23.U7 no. 6170 622.06173U. S. Dept. of the Int. Library


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CONTENTS

Abstract ........................ . ..................... .Introduc t ion .....................Experimental procedure . . . . . . . . . . . . . . . . . . . . . ...........................Experimental resul ts and di scuss ion . . . . . . . . . . .

Magnesium- indiumcalcium a l l oys . . . . . . . . . . Magnesium- indium- s i l i con a l l oys . . . . . . . . . .......................

Cone 1us ions ........................

ILLUSTRATIONSFig.1. Comparison of microstructures.heattreated a t 500 0 C . . . Specimens from extruded rod......................................2.3.4.

1.

2.3 .4.5.6.7.

Comparison of microstructures.heat t reated a t 600 0 C.......Resist ivi ty-composit ion curves:Resist ivi ty-composit ion curves:Specimens from extruded rod. ................................... .magnesium-indium-silicon alloys magnesium-indium-silicon alloys

TABLESMicrostructural observations of m a g n e s i u ~ i n d i u ~ c a l c i u m alloys .Rod} heat t reated a t 500 0 C. . . . . . . . . . Su.nnna.ry of data shown in table 1 ........................X-ray diffract ion analysis of magnesium-indium-ca1cium and magnesium-

indillID- s i l icon alloys .............................................ISu.nnna.ry of microst ructural observations of magnesiuurindium-si1iconal loys . Rod} heattreated at 550 0 C Summary of microst ructural observations of magnesium-indiuursilicon

al loys. Rod, heat t reated at 600 0 C Resis t iv i ty of magnesium-indium-silicon al loys . Rod} heat t reated a t550 0 C .

Resist ivi ty of m a g n e s i u m - i n d i u ~ s i l i c o n al loys . Rod, heat t reated a t600 0 C . .

112334

11

5810

11

4466

799


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r e su l t s of one of the previous i nves t iga t ions and suggest t ha t the r e su l t s ofo ther determinat ions are too h igh . Burke found t h a t the so l id so l u b i l i t y ofcalcium in magnesium decreases from 0 .9 weigh t -percen t a t 516 0 C to 0 .1weight -percen t a t 350 0 C. The so l id so l u b i l i t y of indium in magnesium repor tedby Hansen 5 i s about 52 weigh t -percen t a t 480 0 C, decreas ing to 40 weightpercen t a t 200 0 C. Complete so l id so l u b i l i t y of indium in magnesium i s p r i mari ly l imi ted by d i sp a r i t i e s in c ry s t a l s t ru c tu re and va lence .

EXPERIMENTAL PROCEDURETwo s e r i e s of a l loys were cas t for th i s work: Magnesium-indium-si l icon,

and magnesium-indiurrrcalc ium. Typica l pur i ty l eve l s o f the metals a re l i s t edas fo l lows:

Cel l magnesium--99.76 percen tIndium--99.97 percen tS i l i con- -97 percen t (Ca--O.l percen t maximum, Fe-- l .O percen t maximum)Calciurrr-98 percen t (Balance, l a rge ly CaC12 )Magnesium was melted in a c lay-graph i t e c ruc ib le under a f lux (34 percen tMgC12 , 55 percen t KCl, 9 percen t BaC12 , 2 percen t CaF2 ) and then heated to70 0 0 C for a l l oy i ng . Th e a l loy was heated to 800 0 C, and the tempera ture was

held constan t for 5 minutes to al low for the oxide and f lux to s e t t l e to thec ruc ib le bot tom. The mel t was then cooled to 700 0 C and poured in to a t apereds t e e l mold. Ingots were machined in to b i l l e t s tha t were then formed in to rods0.375 inch in diameter by ext rus ion on a v e r t i c a l pr e s s . The rods were coldswaged to a diameter of 0.350 i nch . Specimens from each hea t were encapsula tedin quar tz glas s tubes for so lu t io n -h ea t - t r ea t in g . A smal l amount of su l f u rplaced i ns ide each capsu le pro tec ted the specimen sur f ace from oxidat ion dur ingheat t rea tment , Th e t ime of heat t reatment a t each temperature wa s increasedu n t i l no fu r the r change in the quenched micros t ruc tures was observed. Thist ime was taken as t h a t required to reach equi l ibr ium. Approximately 0.002inch was machined from the specimen diameter to remove any sur face contanlinat ion produced by hea t t r ea tment . An addi t iona l 0.150 inch was machined o f fthe diameter) and these tu rn ings were submi t ted for chemical a na l y s i s . At30 0 C) the r e s i s t an ce of each heat t rea ted magnes ium-indium-s i l icon rod wasmeasured on a s tandard Kelvin br idge . The re s i s t ance of each specimen wasmeasured twice to three decimal places and then averaged. Th e var ia t ion inread ings was in the l a s t decimal place . The f i n a l ca lcu la ted r e s i s t i v i t yvalues given in the t ab les a r e r epor ted to two decimal places . Each of theca lcu la ted r e s i s t i v i t i e s was cor rec ted fo r indium con ten t v ar i a t i o n from nomi na l ) so t ha t a change in r e s i s t i v i t y , if any, would be the r e s u l t of a changein s i l i co n so l id so l u b i l i t y in magnesium. This was accomplished by p lo t t i n gthe r e s i s t i v i t y aga ins t indium conten t of magnesiurrrindium a l loys in the rangeof 2 to 10 weigh t -percen t indium. The s lope o f th i s l ine was 2.30 micro-ohmcent imeters per a tomic-percen t indium. This s lope was then mul t ip l ied by thedi f fe rence between the a c t ua l indium conten t and the nominal for each specimen.This product was then added to the measured r e s i s t i v i t y .5 Page 84 9 of work c i t ed in footnote 3 .


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EXPERIMENTAL RESULTS AND DISCUSSIONMagnesium- Indium-Calcium Alloys

Table 1 gives the chemical analyses of these alloys and a summary ofmicrostructural observations of heattreated magnesium-indium-calcium specimens. There was no apparent difference in microstructures between specimensheattreated a t 500 0 C for 180 hours or 300 hours. This would establ ish thetime required to reach equilibrium a t something less than 180 hours of heattreatment a t this temperature. Table 2 summarizes table 1) establ ishing thatindium addit ions do not increase the sol id so lubi l i ty of calcium in magnesium.Burke's6 data show the sol id solubi l i ty of calcium in magnesium to be 0.8weight-percent a t 500 0 C. With as l i t t l e as 2 weight-percent indium) the solidso lubi l i ty of calcium is reduced to about 0.14 weight-percent . Increasedindium content above 2 weight-percent lowered the sol id solubi l i ty of calciumsomewhat below 0.14 weight-percent to about 0.10 weight-percent . In figure 1)the microstructure of a binary magnesium-calcium al loy is compared with thoseof magnesium-calcium alloys containing indium from 2 to 20 weight-percent.Second phase part ic les in both the binary and ternary al loys are simi lar insize) although most of the part icles in the ternary al loys appear to be morerounded than those of the binary al loy. Polished specimens of indiumcontaining alloys were etched with numerous magnesium etchants) and a l l specimens showed staining of the matrix and second phase. However) s t ructures ofthe binary magnesium-calcium al loy were not stained by etching with the sameetchants .

Filings from several of the heat t reated magnesium-indium-calcium al loyswere submitted for X-ray diffract ion analyses to determine) i f possible) theident i ty of second phase par t ic les . No pat terns were ident i f ied other thanalpha magnesium. Results are presented in table 3.

An attempt was made to concentrate the second phase by acid dissolutionof one of the ternary al loys; however) X-ray dif f ract ion of the residue gaveonly an indium pat tern.Although second phase part icles in the ternary alloys were not identif ied

by X-ray diffract ion) chemical etching characteris t ics and part ic le shape suggest that these part icles are not Mg2 Ca) but rather a ternary or an indiumcalcium compound. A binary compound CaIn has been ident i f ied in theindium-calcium system.? The formation of a compound containing calcium andindium could account for the reduced solubi l i ty of calcium in magnesium withindium addi t ion.

6Work ci ted in footnote 4.7Page 399 of work ci ted in footnote 3.


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NominalIn2.002.002.002.002.005.005.005.00

10.0010.0010.0010.0010.0020.0020.0020.0020.0020.00

TABLE 1. - Microstructural observations of m a g n e s i u ~ i n d i u ~ calcium al loys . Rod, heat t reated a t 500 0 C

Analysis weight-percent Number of phases af ter heat treatmentChemical Nominal Chemical a t 500 0 CIn Ca Ca For 180 hours For2.05 0.2 0.03 12.05 .4 .03 11.96 .8 .12 12.30 1.0 .16 22.10 1.5 .49 2

4.89 .8 .10 24.69 1.0 .16 25.09 1.5 .35 29.98 .2 .06 110.07 .4 .07 19.88 .8 .11 29.78 1.0 .25 29.78 1.5 .49 2

20.54 .2 .05 119.56 .4 .08 119.56 .8 .13 219.56 1.0 .21 219.95 1.5 .80 2

TABLE 2. - Summary of data shown in table 1of Ca in Mg,ercent Ca

2 to 0.16510 to .1120 to . l3Burke, E. C. Solid Solubil i ty of Calciumin Magnesium. Trans. AIME, v. 203,1955, p. 285.

M a g n e s i u m - I n d i u ~ S i l i c o n Alloys

300 hours111222221122211222

Tables 4 and 5 give the chemical analyses of these alloys and also summarizemicrostructura l observations of m a g n e s i u ~ i n d i u m - s i l i c o n specimens heattreateda t 550 0 C and 600 0 C. Equilibrium was established a t some time less than 96hours for both heat treatment temperatures because examination of specimensheat t reated beyond 96 hours showed no structure change. Most of the s tructurescontained fair ly well defined second phase part ic les as shown in figure 2; however, a few of the alloys with 2 weight-percent indium contained only scat teredsmall part ic les in the matrix. These part ic les could not be defini tely establ ished as second phase part ic les .


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A B

o

c D

E

FIGURE 1. - Comparison of Microstructures. (A) Mg-3.25 weight-percent Ca, (8) Mg-2.30wei ght-percent In-0.16 weight-percent Co, (C) Mg-4.69 wei ght-percent In-0.16weight-percent Co, (D) Mg-9.88 weight-percent In-O.ll weight-percent Co, (E)Mg-19.s6 weight-percent In-O.l3 weight-percent Ca. Specimens from extrudedrod, heattreated at 5000 C. X 500.


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TABLE 3. - X-ray di ffrac t ion analysis of magnesiurrrindium-calciumand magnesiurrrindium-silicon alloys

Composition, Results from x-ray patternswei.eht-percent Conditionl Sample preparation Major MinorIn Ca Si2.10 .49 - A Filings Mg -5.09 .35 - A do. Mg -9.78 .49 - A do. Mg -19.95 .80 - A do. Mg -19.95 .80 - A Acid extract ion In -5.89 - 0,070 B do, Mg Mg (OH)221.0 - 050 B do Mg (OH)2 Mg, In2.25 - .084 B Filings Mg Mg2 Si25.42 - .075 B do. Mg M&e Si29.70 - .070 B do. Mg Mg2 Si220.10 - .056 B do. Mg Mg2 Si2

lA = extruded and heattreated a t 500 0 C for 300 hrs, water-quenched.B = extruded and heattreated a t 550 0 C for 192 hrs , water-quenched.2On1y strongest l ine of this compound present on pattern.TABLE 4. - Sunwary of microstructural observations of magnesiunrindium-silicon al loys . Rod, heattreated a t 550 0 CAnalysis weight-percent Number of phases af ter heat treatmentNominal Chemical Nominal Chemical a t 550 0 C

1

In In Si S1 For 96 hours For 192 hours2.0 2.20 0.010 0.010 12 122.0 2.05 .025 .037 12 122,0 2.22 .050 .051 2 22.0 2.16 .075 .051 2 22.0 2.25 .100 .084 2 25.0 5.59 .010 .042 2 25.0 5.61 .025 .047 2 25.0 5,89 .050 .040 2 25.0 5.43 .075 .070 2 25.0 5.42 .100 .075 2 2

10.0 9.9 .010 .033 2 210.0 9.9 ,025 ,051 2 210.0 9.9 ,050 .051 2 210.0 10.0 .075 .075 2 210.0 9.9 .100 070 2 2Matr1x conta1ned numerous small part ic les that could not def1nitely bedescribed as second phase by optical microscopy.


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TABLE 5. -

________~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ - - - - - - ~ N u m b e r o f phases a f t e r heat t rea tmentNominal a t 600 0 CIn i For 96 hours For 192 hours2.02.02 .02.02

5.05.05.05.05.0

1.691.821.811.831.854.674.644.704.464.40

0.010

.075.100

.050

.100

O..042.051.089.028.047,051

22222

22222

22222

22222

10.0 9.60 .010 2 210,0 9.60 .050 2 210,0 9.58 .075 2 210,0 9.80 .100 2 2lMatr ix contained numerous smal l tha t could not def in i bedescr ibed as second opt ica l microscopy.

A comparison of the microst ruc tures of the te rnary al loys with the micros t ru c t u re of a b magnesium-silicon al loy ( f ig . 2) shows that the secondphase par t ic les are s imi lar in s i ze and shape. The chemical e charac-t e r i s t i c s were also These observations ind ica te tha t the secondphase in the i s iden t i ca l to the second in theal loy and tha t both second S i . Both acid extract ion residuesand f i l ings from severa l were submit ted for X-ray di f f rac t ionana lys i s . Results ( tab le 3 show the compound Mg2 Si to be a possib le const i t -uent in submit ted No Si was repor ted from the acidex t rac t ion res idues . The dissolved in the ac id .

To corrobora te the metal ic and X-ray s tud ies , a ser ies of re s i s -t i v i ty measurements was made. Res i s t iv i t i e s of hea t t rea ted specimens wereplo t t ed t atomic-percent s i l icon for each l eve l o f indium added. As ther e s i s t i v i t y values were correc ted for minor var ia t ions in indium content , achange in res i s would indicate a change in s i l icon so l id solubi inmagnesium. Resis values appear in tables 6 and 7, and plo ts of thetabula ted data are shown in 3 and 4. Although there i s sca t t e r in thedata , r e s i s t i v i t i e s of the rods are essen t i a l ly equal a t the various levels ofindium content for each heat - t rea tment temperature. A s of the combineddata from r e s i s t i v i measurements, X-ray di f f rac t iongraphic examinations ind ica tes tha t the sol id so lub i l isium is very l imi t even a t 600 0 C, Adding 2 to 10

s i l icon a did not measurably increase thes i l i con in magnesium. Indium did not combine with swas in sol id solut ion with the magnesium,

in magneindium to

so l id solubi ofit


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o

D

A B

o 1

c DFIGURE 2. - Comparison of Microstructures. (A) Mg-0.08 weight-percent Si, (B) Mg-l.83

weight-percent In-O.OSl weight-percent Si, (C) Mg-4.46 weight-percent In-O.OSlweight-percent Si, (D) Mg-9.80 weight-percent In-O.OSl weight-percent Si.Specimen from extruded rod, heattreated at 600 0 C. X SOO.


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TABLE 6. - Resist ivi ty of magnesiunrindium-siliconal loys. Rod, heattreated a t 550 0 CAnalysis atomic- percent Resist ivi ty 10- 6 ohm-emNominal Chemical Uncorrected 1 Corrected

In In Si0.430 0.474 0.009 5.58 5.48.430 .442 .033 5.56 5.53.430 .479 .045 5.59 5.48.430 .466 .045 5.53 5.45.430 .486 .074 5.61 5.481.10 1. 24 .038 6.88 6.561.10 1.24 .043 7.04 6.721.10 1. 31 .036 7.05 6.571.10 1.20 .063 6.97 6.741.10 1.20 .068 7.01 6.782.30 2.28 .031 9.20 9.252.30 2.28 .048 9 . 34 9.392.30 2.28 .048 9.17 9.222.30 2.30 .Oll 9.31 9.312.30 2 28 ,066 9.31 9.361 ResIstIvIty values In thIS column were correctedfor variat ion in indium content from nominal.

Corrected values appear in the l as t column.TABLE 7. - Resist ivi ty of magnesium-indiuITrsi1iconal loys. Rod, heat t reated at 600 0 C

Analysis atomic-percent Resist ivi ty 10- 6 ohm-emNominal Chemical Uncorrec t e d ~ CorrectedIn In Si0.430 0.363 0.020 5.56 5. II.430 .391 .037 5.56 5.65.430 .389 .025 5,68 5.77.430 .394 .045 5.60 5.68.430 .398 .078 5,64 5. II1.10 1.03 .025 7.01 7.171.10 1.02 .038 6.96 7.141.10 1.03 .042 6.93 7.101.10 .980 .046 7.01 7.291.10 .966 .042 7.03 7.342.30 2.20 .044 9.08 9.312.30 2.20 .026 9.09 9.322.30 2.20 .031 9,33 9.562.30 2.25 .047 9 32 9 43

lResis t ivi ty values in this column were correctedfor variation in indium content from nominal.Corrected values appear in the las t column.


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2 we ght -percen t ind ium addi t ion5 0.01 0.02 0.05 0.06 0.07 0.08 0.1

Si l l CON, otomic percent Each point on overage of two readings

FIGURE 3. - istivi tion Curves: Magnesi um-Indi um-Si l icon Alloys.Rod, h C for 192 hours, water-quenched.


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EuIE.c

0

>-I->l -f./)f./)wc::

X 10- 61 0 r - - - - . - - - - - . - - - - , , - - - - . - - - - - . - - - - . - - - - - . - - - - . - - - - - ~ - - - ~ ..

.. ..

9 10 weight -percent indium addit ion

8

....

.. ..

7 ..5 weight-percent indium addi t ion

6

2 weight percent indium addi t ion__ ____ _____L____ ____L___ ____ ____ ____ __

0.05 0.06 0.07 0.08 0.09 0.1SILICON, atomic-percent

FIGURE 4. -II Each point an average of two readings

istivity-Composition Curves: Magnesium-Indium-Silicon Alloys.heottreated at 600 0 C for 1

CONCLUSIONSindium element with high sol id solubi l i in magnesium) to

11

magnesium-calcium al loys reduces the sol id so lubi l i of calcium in magnesium.indium reduced calcium sol id solubi l i ty by a factor of

s ix .Indium did not affec t the sol id solubil of si l icon in magnesium.

IN .. aU .O f MI S .? ~ , A .

ri6170 indium effect onsi and ca solid soubility in mg

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