Ternary Al–Ni–Ru phases

Journal of Alloys and Compounds 351 (2003) L1–L5

L

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Letter

Ternary Al–Ni–Ru phases S. Mi b

a,b ,

*, B. Grushko a , C. Dong b , K. Urban a

a ¨ Festkorperforschung ¨ ¨ ¨ , Forschungszentrum Julich GmbH, D-52425 Julich , Germany Institut f ur Department of Materials Engineering, Dalian University of Technology, Dalian 116024, PR China

Received 22 August 2002; accepted 28 August 2002

Abstract Four stable ternary crystalline phases were identified in the Al-rich part of the Al–Ni–Ru phase diagram using powder X-ray diffraction and electron microscopy. They are monoclinic with an approximate composition of Al 82.4 Ni 12.0 Ru 5.6 (a50.8636(3) nm, b50.6333(2) nm, c50.6273(3) nm, b 595.12(3)8, isostructural to Al 9 Co 2 ), hexagonal with a composition of Al 75.5 Ni 16.0 Ru 8.5 (a51.2132(3) nm and c52.7020(9) nm), orthorhombic with a composition of Al 76.0 Ni 8.0 Ru 16.0 (a51.4960(6) nm, b50.8253(3) nm, c51.2668(6) nm, isostructural to O-Al 13 Co 4 ) and cubic with a composition of Al 71.8 Ni 11.2 Ru 17.0 (a50.7674(2) nm, isostructural to C-Al 5 Rh 2 ).  2002 Elsevier Science B.V. All rights reserved. Keywords: Transition metal alloys; Crystal structure; TEM; X-ray diffraction

1. Introduction The Al-rich part of the Al–Ni–Ru phase diagram was studied previously [1,2]. However, the information provided in these publications is not very detailed. In particular, in Ref. [1] the existence of a ternary phase designated |RuNi 2 Al 14 was mentioned but its structure was not determined. In Ref. [2], a ternary phase, also designated |RuNi 2 Al 14 , was reported in a wide range of 7–11 at% Ru and 70–81 at% Al. On the other hand, there are reports on the formation of stable quasicrystalline phases in the Al-rich part of this system whose relation to the phases described in Refs. [1,2] was not investigated. In particular, there are decagonal (D) phases [3] with a periodicity of about 0.4 and 1.6 nm along the 10-fold lattice direction and an icosahedral (I) phase [4]. In the present paper, we report on a study of the Al-rich part of Al–Ni–Ru. Four ternary intermetallic compounds were found in addition to a decagonal phase with 1.6 nm periodicity. In the present contribution, the overall compositions and diffraction data for these phases are reported.

*Corresponding author. Tel.: 149-2461-612-412; fax: 149-2461-616444. E-mail address: [email protected] (S. Mi).

The detailed phase equilibria in Al–Ni–Ru are presently under investigation.

2. Experimental The alloys were produced from constituent elements by levitation induction melting in a water-cooled copper crucible under an Ar atmosphere. The purity of Al was 99.999%, of Ru 99.9% and Ni 99.999%. The ingots were typically of about 5 g. The dissolution of Ru in Al is difficult in the Ru-rich alloys. The samples were re-melted again if after inspection undissolved Ru was detected in broken ingots. This procedure was repeated until microscopically homogeneous ingots were obtained. Single-phase samples were selected using powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The compositions were examined by inductively coupled plasma optical emission spectroscopy (ICP-OES) and by energy-dispersive X-ray analysis (EDX) in SEM. Powder XRD was carried out in the transmission mode using Co Ka 1 radiation and a position-sensitive detector. The samples were also studied by electron diffraction in a transmission electron microscope (TEM) operated at 200 kV. The TEM samples were powders spread on Cu grids covered by carbon films. The melting temperatures of the

0925-8388 / 02 / $ – see front matter  2002 Elsevier Science B.V. All rights reserved. PII: S0925-8388( 02 )01020-4

S. Mi et al. / Journal of Alloys and Compounds 351 (2003) L1 –L5

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Table 1 Diffraction data of the monoclinic Al 9 (Ni,Ru) 2 of the Al 81.9 Ni 12.0 Ru 6.1 composition No.

h

k

l

I /I0

1 2 3 4 5 6 7 8 9 10 11 12 13

1 0 2 21 1 22 2 2 22 0 1 0 21 21 22 3 1 23 22 22 3 2 2 21 4 3 1 24 23 23 4 0 4 0 21 21 3 2 2 1 22 24 22 23 2 4 24 0 21 21 4 3 1 5 22 4 25 3 2 24 3

1 1 0 1 1 0 1 0 1 0 2 2 1 2 0 1 1 1 1 2 1 2 1 2 0 2 2 0 1 2 1 3 0 1 1 3 1 2 3 1 1 0 3 2 0 2 1 3 3 2 0 3 2 1 3 1 1 3 3 0 1

0 1 0 1 1 1 0 1 1 2 0 1 2 1 2 0 2 1 2 1 1 1 2 2 0 0 2 1 2 1 0 1 1 3 3 1 2 2 0 3 3 2 1 2 3 0 2 2 2 3 2 0 3 0 2 2 1 1 2 3 3

14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47

d obs

d calc

43 78 13 47 55 31 42 26 8 28 42 5 9

0.50969 0.44433 0.43006 0.40523 0.38741 0.36964 0.35522 0.33985 0.32015 0.31201 0.29678 0.28159 0.27243

12 18

0.26377 0.26085

8 11 32 16 48 62 38 12 43

0.24813 0.24379 0.24028 0.23377 0.23210 0.22688 0.21898 0.21526 0.21225

82

0.20921

45 32 48 93

0.20563 0.20370 0.20023 0.19757

100

0.19641

16

0.19286

10

0.18943

7 6 7 8

0.18595 0.18502 0.18339 0.18124

12

0.17783

6 6

0.17489 0.17327

17

0.17007

9 6 8 11

0.16826 0.16594 0.16495 0.16414

6 6 10

0.16196 0.15920 0.15681

0.50999 0.44478 0.43009 0.40574 0.38523 0.37003 0.35580 0.34037 0.31949 0.31241 0.29716 0.28245 0.27291 0.27162 0.26422 0.26120 0.26034 0.24828 0.24385 0.24059 0.23431 0.23184 0.22661 0.21870 0.21505 0.21254 0.21207 0.20916 0.20892 0.20540 0.20363 0.19999 0.19798 0.19785 0.19649 0.19604 0.19283 0.19262 0.18950 0.18934 0.18582 0.18501 0.18336 0.18140 0.18122 0.17790 0.17759 0.17491 0.17310 0.17308 0.17019 0.17000 0.16813 0.16602 0.16493 0.16436 0.16400 0.16188 0.15927 0.15676 0.15675

Table 1. Continued No.

h

k

l

I /I0

48 49

23 24 25 22 5 4 1 1 22 3 22 3 6 4 0 0 21 24 26 6 23 1 3 6 4 25

2 1 1 0 2 3 4 1 1 3 4 2 0 0 4 2 2 3 1 0 4 2 4 1 3 3

3 3 2 4 0 0 1 4 4 2 1 3 0 3 2 4 4 2 1 1 1 4 1 1 2 1

50 51 52 53 54 55 56 57 58 59 60 61 62 63

d obs

d calc

9 9

0.15391 0.15216

11

0.15125

10

0.15046

10

0.14710

8 7 11 11

0.14616 0.14554 0.14403 0.14329

21 24

0.14122 0.14003

11

0.13907

5 6

0.13713 0.13660

7

0.13399

11

0.13239

0.15393 0.15217 0.15213 0.15121 0.15117 0.15065 0.15052 0.14719 0.14708 0.14611 0.14556 0.14407 0.14336 0.14335 0.14123 0.14009 0.14005 0.13914 0.13905 0.13709 0.13656 0.13654 0.13409 0.13399 0.13249 0.13230

The d-values are in nanometers. Reflections with intensity below 5% are not presented. a50.8636(3) nm, b50.6333(2) nm, c50.6273(3) nm; b 595.12(3)8; V50.3417(1) nm 3 .

Fig. 1. The overall compositions of the ternary Al–Ni–Ru phases (m: monoclinic Al 9 (Ni,Ru) 2 ; O: orthorhombic O-Al 13 (Ru,Ni) 4 ; H: hexagonal H-phase; D: decagonal phase; C: cubic C-phase).

S. Mi et al. / Journal of Alloys and Compounds 351 (2003) L1 –L5

L3

]] ] Fig. 2. Electron diffraction patterns of the H-phase: (a) [0001], (b) [2110] and (c) [0110] zone axes.

phases were determined by differential thermal analysis (DTA) with a rate of 5–20 8C min 21 .

3. Results The overall compositions of the equilibrium phases observed in Al–Ni–Ru are shown in Fig. 1. A monoclinic phase was observed in a compositional range extending at almost constant 82 at% Al between 4.5 and 7.0 at% Ru. This phase is associated with RuNi 2 Al 14 reported in Ref. [1]. Its powder XRD pattern was very similar to that of Al 9 NiFe of the Al 9 Co 2 type structure [5]. Suggesting the same structure, we indexed it with lattice parameters a5 0.8636(3), b50.6333(2), c50.6273(3) nm and b 5 95.12(3)8 for the Al 82.4 Ni 12.0 Ru 5.6 composition (see Table 1). The space group P21 /a and formula Al 9 (Ni,Ru) 2 are suggested by analogy with Al 9 Co 2 . Al 9 (Ni,Ru) 2 melts at about 783 8C as determined by DTA. The H-phase is formed in a small range around Al 75.5 Ni 16.0 Ru 8.5 . Electron diffraction (Fig. 2) revealed a hexagonal structure with lattice parameters of a51.23 and

c52.72 nm. The corresponding powder XRD pattern was indexed correspondingly (see Table 2). The refined lattice parameters are a51.2132(3) and c52.7020(9) nm. DTA revealed a reaction at about 930 8C associated with the melting of the H-phase. The D-phase with 1.6 nm periodicity along the 10-fold direction is formed close to the H-phase composition around Al 73 Ni 16 Ru 11 . The observed diffraction patterns of this phase are similar to those reported and characterized in Ref. [3]. The D-phase solidifies below 1057 8C (DTA data) and persists during annealing for 100 h at 1000, 950 and 900 8C. An orthorhombic phase was observed below 1000 8C in a small compositional range around Al 76.0 Ni 8.0 Ru 16.0 . The lattice parameters determined from the electron diffractograms (see Fig. 3) were: a51.52, b50.84 and c51.29 nm. The diffraction pattern is very similar to that associated in Ref. [6] with Al 3 Co (O-Al 13 Co 4 in Ref. [7]). This allowed us to suggest the same orthorhombic structure. We designate it O-Al 13 (Ru,Ni) 4 . The lattice parameters for Al 76.0 Ni 8.0 Ru 16.0 refined from the powder XRD data (see Table 3) were a51.4960(6), b50.8253(3) and c5

Fig. 3. Electron diffraction patterns of the O-Al 13 (Ru,Ni) 4 : (a) [100], (b) [010] and (c) [001] zone axes.

S. Mi et al. / Journal of Alloys and Compounds 351 (2003) L1 –L5

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Table 2 Diffraction data of the hexagonal H-phase of the Al 75.5 Ni 16.0 Ru 8.5 composition No.

h

k

l

1 2 3 4 5 6 7 8 9 10 11 12 13 14

1 2 1 2 2 2 2 1 3 3 2 3 2 2 3 2 3 3 2 1 4 3 4 3 2 3 3 3 4 2 0 2 3 1 3 1 4 5 3 2 0 5 2 5 3 3 3 4 3 2 0 5 3 5 3 6 2 5 3 4 5

1 0 1 0 1 1 0 1 0 0 0 0 1 0 0 2 0 1 2 0 0 1 0 1 0 2 2 1 1 2 0 0 1 0 0 1 1 0 1 1 0 0 0 0 2 3 0 2 2 0 0 1 1 0 1 0 1 0 2 1 2

2 2 4 4 1 2 5 6 0 1 6 3 5 7 4 0 5 3 4 10 1 5 4 6 10 1 3 7 1 8 12 11 8 12 10 12 5 0 9 11 13 2 12 3 7 0 11 2 8 13 14 1 11 8 12 2 14 9 11 12 5

15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42

I /I0

d obs

d calc

7 6 7 9 22 17 13 40 13 13 65 22 23 8

0.55588 0.49035 0.45224 0.41378 0.39287 0.38097 0.37637 0.36254 0.34993 0.34710 0.34186 0.32625 0.31965 0.31047

12 5 7

0.30305 0.29379 0.27718

5

0.26124

7 6

0.25669 0.24444

7

0.24055

8

0.23299

6 5

0.22857 0.22548

11 13

0.22267 0.22048

34 7

0.21414 0.21119

11 12

0.20993 0.20916

27

0.20786

25 87

0.20697 0.20467

68 100 27

0.20250 0.20112 0.19617

11

0.19305

5

0.18806

8

0.17824

7

0.17364

6

0.17209

6

0.16066

0.55340 0.48963 0.45134 0.41470 0.39291 0.38101 0.37669 0.36159 0.35023 0.34733 0.34191 0.32642 0.32001 0.31106 0.31093 0.30331 0.29391 0.27726 0.27670 0.26169 0.26144 0.25650 0.24482 0.24466 0.24028 0.24009 0.23285 0.23258 0.22846 0.22567 0.22517 0.22252 0.22064 0.22017 0.21393 0.21109 0.21107 0.21014 0.20911 0.20890 0.20785 0.20764 0.20696 0.20464 0.20446 0.20221 0.20111 0.19645 0.19620 0.19327 0.19300 0.18825 0.18782 0.17842 0.17818 0.17366 0.17359 0.17216 0.17205 0.16065 0.16064

Table 2. Continued 43 44 45 46 47 48 49 50 51 52

3 1 5 3 5 5 5 5 0 2 3 7 7 6 6

2 0 2 3 2 1 3 3 0 1 1 1 1 2 0

13 17 8 12 9 12 5 6 19 18 17 0 1 6 12

5

0.15730

5

0.15049

6 6

0.14670 0.14459

18

0.14231

6 6 5

0.14053 0.13942 0.13908

6 6

0.13864 0.13813

0.15741 0.15715 0.15060 0.15045 0.14677 0.14463 0.14463 0.14240 0.14221 0.14042 0.13954 0.13917 0.13898 0.13863 0.13823

The d-values are in nanometers. Reflections with intensity below 5% are not presented. a51.2132(3) nm, c52.7020(9) nm; V53.4444(7) nm 3 .

Table 3 Diffraction data of the orthorhombic O-Al 13 (Ru,Ni) 4 phase of the Al 76.0 Ni 8.0 Ru 16.0 composition No.

h

k

l

I /I0

1 2 3 4 5 6 7 8 9 10

0 0 1 3 1 4 2 4 2 1 2 3 4 0 1 3 1 1 4 3 1 2 6 0 2 3 5 1 6 5 4 2 7 5 7 6 4 0

0 2 0 0 2 0 2 0 2 2 1 0 0 0 0 2 1 2 2 3 1 3 1 3 3 1 0 2 2 2 0 2 1 3 0 2 3 4

2 0 3 2 1 0 0 1 1 2 3 3 2 4 4 1 4 3 0 0 5 2 1 3 3 5 4 5 0 3 5 5 0 0 2 2 3 2

11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

26

d obs

d calc

11 10 68 39 7 18 32 12 40 43

0.63245 0.41404 0.40610 0.39158 0.38036 0.37373 0.36180 0.35827 0.34766 0.33704

14

0.32157

5 8

0.31592 0.30924

5

0.28929

5 8 10

0.27677 0.24092 0.23932

5 11 7 10

0.23457 0.23079 0.22044 0.21754

54

0.21323

100

0.20986

94

0.20724

32

0.20228

5

0.19619

0.63342 0.41264 0.40640 0.39182 0.37951 0.37400 0.36131 0.35869 0.34745 0.33686 0.33589 0.32226 0.32205 0.31671 0.30984 0.30835 0.29007 0.28955 0.27711 0.24087 0.23910 0.23909 0.23455 0.23050 0.22027 0.21787 0.21749 0.21370 0.21340 0.21011 0.20976 0.20744 0.20689 0.20251 0.20250 0.20223 0.19622 0.19617

S. Mi et al. / Journal of Alloys and Compounds 351 (2003) L1 –L5 Table 3. Continued No.

h

k

l

I /I0

27 28

1 6 5 7 1 8 9 5 6 9 4 4 1 6

4 3 3 3 3 3 2 4 3 0 4 5 4 1

3 1 3 1 7 2 9 4 5 4 5 2 6 7

29 30 31 32 33 34 35

d obs

d calc

11 7

0.18409 0.18265

5 7

0.16709 0.15034

9

0.14981

9 8

0.14931 0.14720

18

0.14673

14

0.14429

0.18397 0.18281 0.18260 0.16729 0.15043 0.15024 0.14981 0.14968 0.14927 0.14718 0.14709 0.14689 0.14685 0.14421

The d-values are in nanometers. Reflections with intensity below 5% are not presented. a51.4960(6) nm, b50.8253(3) nm, c51.2668(6) nm; V51.5640(8) nm 3 .

Table 4 Diffraction data of the cubic C-phase of the Al 71.8 Ni 11.2 Ru 17.0 composition No.

h

k

l

I /I0

d obs

d calc

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

1 1 1 2 2 2 3 3 2 3 3 4 3 4 4 3 4 4 3 4 5

0 1 1 0 1 1 1 1 2 2 2 0 3 2 2 3 3 3 3 3 2

0 0 1 0 0 1 0 1 2 0 1 0 1 0 1 2 0 1 3 2 1

5 6 15 23 91 30 5 7 5 86 100 19 6 5 7 5 6 5 10 13 6

0.77162 0.54216 0.44216 0.38305 0.34258 0.31268 0.24202 0.23168 0.22178 0.21308 0.20533 0.19213 0.17622 0.17160 0.16748 0.16350 0.15346 0.15046 0.14763 0.14245 0.14004

0.76735 0.54260 0.44303 0.38368 0.34317 0.31327 0.24266 0.23137 0.22152 0.21283 0.20508 0.19184 0.17604 0.17159 0.16745 0.16360 0.15347 0.15049 0.14768 0.14249 0.14010

The d-values are in nanometers. Reflections with intensity below 5% are not presented. a50.7674(2) nm; V50.4518(3) nm 3 .

L5

1.2668(6) nm. Table 3 contains the best fit to the experimental data. It shows fairly similar intensities of the corresponding diffraction reflections as in O-Al 13 Co 4 [7], apart from the reflection which is (002) and not (111) as in O-Al 13 Co 4 . This might be due to a slightly different atomic position in the two phases. Similar to that in Al–Co, the O-Al 13 (Ru,Ni) 4 phase is structurally related to binary monoclinic Al 13 Ru 4 [8]. The C-phase forms in a compositional range of about 9.0–12.0 at% Ni and 72.0–73.0 at% Al. Its powder XRD pattern is very similar to that of C-Al 5 Rh 2 [9], which allowed us to suggest the same primitive cubic structure. This was confirmed by electron diffraction. The lattice parameter of a50.7674(2) nm was obtained for the Al 71.8 Ni 11.2 Ru 17.0 composition from its powder XRD pattern (see Table 4). It is a high-temperature phase observed at 1100 8C but not at 1000 8C or below. DTA revealed a reaction at 1233 8C associated with the melting of the C-phase. It is worth noting that in Al–Ni–Fe a hexagonal phase existing in a similar range [5,10] is isostructural to low-temperature H-Al 5 Rh 2 and Al 5 Co 2 .

Acknowledgements We thank W. Reichert, H. Lippert, S. Balanetskyy and C. Thomas for technical contributions. Financial support from DFG is gratefully acknowledged.

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