EFFECT OF HAFNIUM CONTENT ON MORPHOLOGY EVOLUTION OF γ PRECIPITATES IN P/M Ni BASED SUPERALLOY

48 8 Vol.48 No.8 2012 8 1011 1017 ACTA METALLURGICA SINICA Aug. 2012 pp.1011 1017 Hf Ä Ì ÀÚÈÏ γ ß Ó Ð 1,2) 1) 3) 1) ˲ Å ², 100083 2) ± ² Â, 100081 3) ˲² ² ², 100083 ¹ Hf ÍÆ Ð Ø ¾ γ Æ ¾Ä. Ý : Ð Ø ¾ γ «, Đ Õ «Ì³Æ, «Ì³Æ É Æ «, Í ÖÔ Æ. Hf ÈÓØ Đ Ä, γ ÌÊÃÄ ±ÃÆ «Ï à 2 ÛÚ, γ Á Ç Þ Ü Æ ÄÛ Ç. ÂÍ Æ Ð, Ni 3(Al, Ti), γ ÆÖÔ Æ TG113.12 ÜÞ½Ñ A ÜÅ¼Æ 0412 1961(2012)08 1011 07 EFFECT OF HAFNIUM CONTENT ON MORPHOLOGY EVOLUTION OF γ PRECIPITATES IN P/M Ni BASED SUPERALLOY ZHANG Yiwen 1,2), WANG Fuming 1), HU Benfu 3) 1) School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 2) High Temperature Material Institute, Central Iron and Steel Research Institute, Beijing 100081 3) School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 Correspondent: ZHANG Yiwen, professor, Tel: (010)62186736, E-mail: yiwen64@126.com Supported by National Key Basic Research Program of China (No.2010CB631204) and Sino Russian Intergovernmental Cooperation in Science and Technology Project (No.CR14 20) Manuscript received 2012 03 14, in revised form 2012 05 19 ABSTRACT The cubic γ particle morphologyevolution wasstudied during long time agingprocess in a powder metallurgy (P/M) Ni based superalloy with Hf addition. The results show that, during long time aging process, the cubic γ particle splits into a doublet of plantes or an octet of cubes. The octet of cubes with low energy is a preferred shape, it splits no longer. The γ/γ lattice misfit varies with different Hf contents. The growth or coarsening process of γ precipitate can be roughly divided into interface controlling and strain controlling stages, the γ precipitate morphology is greatly influenced by the elastic interaction energy between γ particles. KEY WORDS powder metallurgy superalloy, Ni 3 (Al, Ti), γ phase morphology stability Î Ñ Æ ßÅ ÐÅ Û Ni 3 (Al, Ti) γ, Æ Á γ Æ Ý γ, ÌÊÀ ÑßÙ. γ Ý Í Ç Çß Ì ÆÅ, Á, º γ Ç Ú Å ½Ï, ߵŠγ Ý Ê Ì,»³ º غ * Í ¹ Ò Ã«2010CB631204 ÐÐ «CR14 20 Ø : 2012 03 14, Ø : 2012 05 19 Ñ : Õ Ó,, 1964, Ø µ, DOI: 10.3724/SP.J.1037.2012.00136 ÐØË [1 3]. ¹ 70 Ï, º [4 7], Î Ñ ÆÎ Hf ß γ ÈÅÛÌ ÍÆ Å. Î Ñ B 1900 Alloy, 713 LC, Udimet700 M M246 ÆÎ 1.3% 2.0%(«, Ð ) Hf Æ Î MC ÈÅÛÆ, Hf ÈÅÛ ÎÈÅÛ±, ±, ÆÎ Hf ² MC ÈÅÛ Ç ß MC È ÅÛ, Ì ÎÆ»Ç ÕÌ Ó, Á Ê ÆÑßÙ [4,5]. ¹, Î Ñ ÆÎ 0.2% 0.8% Hf, ͱ Hf γ γ ßÅ, Ê

1012 ± 48 γ ßÑÙ, γ/γ Ð Ô [8]. Æ Ä ¼ ÈÐ, Æ γ ² Ö (doublet of plantes) Í Ç (octet of cubes), γ Ç Í, dz γ [9 11]. º Hf Ñ Ñ Ù± Æ γ Ç Í± Ç Õ, Á ¾ Ö Â È Ù ß¼. 1 Ð ³ È FGH97 Î Ñ, ÚÅ («, %) : Co 15.75, Cr 9.0, W 5.55, Mo 3.85, Al 5.05, Ti 1.8, Nb 2.6, C 0.04, B 0.012, Zr 0.015; ÆÎ Hf («, %) 0, 0.16, 0.3, 0.58 0.89, Ni Ï. µè ½ Ò Å, Ù 50 150 µm, 5 Å. µè (HIP) ¼Þ, ÅÙ 1200, 4 h, AC+ ±, µ ± ÅÙ 700, 15 20 h, AC. Ñ Ù± ÅÙ : ± ÑÙ 550, 650, 750 850, ± ±Ð 500, 1000 5000 h. Hf FGH97 ¾ ( Ç 8 mm, 8 mm) Æ 1200, 2 h, AC ¼. ¼ ³ ±, ¾ 1200, Ñ 10 min, 0.01 3 /s ¼ ż 500 ³ ¼ ½Ñ. È JSM 6480Lu Ò (SEM) ZEISS Sup RA 55 ¼ Ò (FEG SEM) ¾º. SEM ¾ µèòßò Òß ²Å, Ò ßÒ ÅÙ : 20%H 2 SO 4 +80%CH 3 OH(Í ) Òß, Ò 25 30 V, ±Ð 15 20 s; Òß ²Å Ù 170 ml H 3 PO 4 + 10 ml H 2 SO 4 +15 g CrO 3 Òß, Ò 3 5 V, ±Ð 3 5 s. γ ÇµÈ Image pro Plus 6.0 Ô. µèòå º γ, ÈÅ Ý Õ Hf FGH97 Æ γ, γ º 1%» +1% ÐÍ, ÑÙ 5, ÒÁÎÙ 0.025 0.03 A/cm 2. ß ¾ ( Ç 10 mm, 1 mm), È D/max 2500H X ½ (XRD) ¹ Õ. È Origin8.0 Ô Î PEM ß Æ γ γ ½ ½, ¹À γ γ «¾, µè δ = 2(a γ aγ) a γ +a γ, À «ÉÔÙ (Ú Æ, δ ÉÔÙ, a γ a γ γ γ «¾ ). 2 Ð Îà 2.1 FGH97 É Á Ê ÝÙ «1 ± 0.3%Hf FGH97 Æ 1200, Ø 1 0.3%Hf FGH97» ¾ γ É Fig.1 Morphology of γ precipitates in the FGH97 alloy with 0.3%Hf after solution treatment 4 h, AC ¼ γ Ê. ², Æ ¼, «Ý Í Ð γ ( Ç 100 200 nm). 2.2 Ò Ö Hf Å FGH97 É γ 2 ± ¼ ÅÐ Hf FGH97 γ Ê. ²Ó, 3 /s ¼ Ð, Hf Ʋ¾º ÎÙ γ, ( 2a); Î 0.3%Hf Æ, γ Ð Ñ, Ç Í ( 2c); 0.89%Hf Æ, Ñ γ ³, Ç ÌÃÑÍ ( 2e). Ù 3 /s ¼ Ð, Hf γ ÇÙ, Ù»Á Æ Í± γ ÇËÊ Ð Ç,, Æ Ã. ¼ Å 0.01 /s ±, Æ γ Ê Å. Hf Æ γ ÇÑÍ, Ð, Å Ö, À γ ÚÐÝ ( 2b); 0%Hf, 0.3%Hf γ ( 2d), ËÎ γ Æ À γ Í Å, Ð, ²»Á γ {100} 4 º µ; Hf 0.89% Æ, Í Ç γ, Ñ Í γ Ç, γ ( 2f). ²Ó, ¼ ÅÙ ±, Á Hf Ñ, Æ γ Í Ð Ç±, γ Í Ê Ç. 2.3 Ö Hf Å FGH97 É γ Ë Ç Æ¼ + À±, Hf 0, 0.3% 0.8% FGH97 Æ, γ Å (Ni 0.852 - Co 0.148 ) 3 (Al 0.783 Ti 0.129 Nb 0.088 ), (Ni 0.855 Co 0.145 ) 3 - (Al 0.778 Ti 0.129 Nb 0.088 Hf 0.005 ) (Ni 0.857 Co 0.143 ) 3 - (Al 0.767 Ti 0.129 Nb 0.088 Hf 0.016 ). 3 γ Æ Nb Ti ËÌ Å, Co Æ Ni, ²

j8s pend : Hf ;;yit ka t!z << γ MaM 1013 B f!z/dl b Q 2 Hf FGH97 γ Fig.2 Morphologies of γ precipitates in the FGH97 alloys with different Hf contents at different cooling rates (a) 0%Hf, 3 /s (b) 0%Hf, 0.01 /s (c) 0.3%Hf, 3 /s (d) 0.3%Hf, 0.01 /s (e) 0.89%Hf, 3 /s (f) 0.89%Hf, 0.01 /s A P Ni Al Æ Ni. I!C Æ Hf ==mj, γ Æ Hf = = mj, Al = = n, [ Hf & P Al, Hf 7 _ γ Æ. ^ 3 %A?"[ Hf == FGH97 C Æ0 E3 `% G γ R. &A A, "[ Hf == C Æ γ RT[ "[. u Hf C Æ, γ A5l6 h, ^ 3a K+, γ +A =q mb., γ VuU, =Ou, bh 250 nm. \C Æ Hf ==h 0.3% %, γ =OuU, bh 450 nm, 2._ U=O6 γ B A, )! D S % 6 D, A mb6 6 U γ (^ 3b). ~ = 0.89%Hf C Æ, γ =O[ n, 6 γ B ia [,b,, ua[ γ 3? 6 D 8 6 U, p [12] 9A [? u= l. 3I Hf ==S 0 mj 0.89%, γ = >S 61.9% m 62.7%, Y γ = > mj "[, ^ γ D : ; " N γ = >. ;z8 [, e=\c Hf Vj[ M γ O"sq, ~ γ 'l # O. M 0.3%Hf = FGH97 QXY3rw>5hk R= γ p h?. "[% mu} γ DGNg OQ y, $P= 0.3%Hf C 550, 650 750 }4 u% E3. ^ 4 %A? 0.3%Hf C Æ0 + `% "[mu}æ 5000 h 4u% γ R. ^ 4a h= 0.3%Hf C 0 + `% G γ 2.4

7 % 1014 j 48 t 3!Z Hf << FGH97 B D2Fb γ Q Fig.3 Morphologies of γ precipitates in the FGH97 alloys with 0%Hf (a), 0.3%Hf (b) and 0.89%Hf (c) after solution and aging treatment t 4 < 0.3%Hf b FGH97 B 3t$ Fb γ Q Fig.4 Morphologies of γ precipitates in the FGH97 alloy with 0.3%Hf after solution and tertiary aging treatment (a), and after 5000 h aging at 550 (b), 650 (c) and 750 (d)

8 Ô Ò : Hf Ý Ì γ Å Å 1015 Ç. ÞÃ, ± γ Ð, γ º, γ, ± γ Ñ. Æ 550 Ù ±, Í Ç γ ¼ {100}, γ dz Ð, À γ Í Ý ÆÅ, γ Ç ( 4b). 650 ± Ð γ Í, γ, Ñ Í Ç γ {100}«( 4c). 750 ± γ, γ Ç Ê Ç (preferred shape) Â Í Ç µ LSW(Lifshitz Slyozov Wagher) ÄÅ [13], γ, Ç Ò, À γ ÄÅ ( 4d). 2.5 Ö Hf Å FGH97 É ĐÊ ÝÙ «5 ± Hf FGH97 Æ 850, 1000 h Ù± γ Ê. ²Ó, Ù Hf Æ γ, Í Ç, 100 Đ Ñ ( 5a); 0.3%Hf Æ γ Ç ÄÅ ( 5b), Ù Ù Hf, 0.3%Hf γ ±Ð³, LSW Ä Å ÇÜÛ [13] ; Hf Ñ 0.89%, Æ Ç γ Đ ÅË, Ù γ µ Ç γ ß Í Ç γ Í, γ ÇÒ, γ ßÍ Ú Ç, À γ ÄÅ ( 5c). Ë Þ ² : 850 Ù± Æ, Hf γ ±Ð, Á Hf Ñ ²Ù LSW ÄÅ ÇĐÔ. 1 ± 850, 1000 h ± Þ, Hf FGH97 Æ γ γ «¾ γ /γ ÐÜÉÔ Ù. ²Ó, ± ÞÁ Æ Hf Ñ, Hf γ Æ, «¾ Ñ, γ /γ ÉÔÙ ß ÕÒ, Æ 850 ѱ, ÉÔÙ ß Å Ã, Ù Î γ /γ ÐÜÉÔÙ»Ë Å Õ,, α Æ TCP Ë À γ Ý ¾ 1 Hf FGH97 850, 1000 h Ý γ γ Å ½ γ /γ ÛÈÓØ Table 1 Lattice constants of γ and γ (a γ and a γ ) and lattice mismatch of γ and γ (δ) in the alloys with different Hf contents before and after 1000 h aging at 850 Hf content, % Condition a γ, nm a γ, nm δ, % 0 Before 1000 h 0.359706 0.359281 0.118 0.3 aging 0.359706 0.359438 0.075 0.89 0.359706 0.359533 0.048 0 After 1000 h 0.359290 0.358962 0.092 0.3 aging 0.359380 0.359053 0.091 0.89 0.359610 0.359325 0.080 Ø 5 Hf FGH97 850, 1000 h γ É Fig.5 Morphologies of γ precipitates in the FGH97 alloys with 0%Hf (a), 0.3%Hf (b) and 0.89%Hf (c) after 1000 h aging at 850

1016 ± 48 ¹ Ä ÑÍ, µ γ Ðܾ ÑÍ. 3 Õ Á ³ Þ ², ßÎ Hf FGH97, γ ÄÅ ÆÊ Ð Ç±, γ. Hf, γ µ± Ð. γ, γ Í Ç Ê Ç. Á Ù± ±Ð», Ç Ê Ç, Ý Ð µå ÜÛ. ÜÛ, Â Í γ Ç ßÍ, γ ÄÅ Ã LSW ÄÅ Ç. 3.1 γ Ô (splitting) Ñ Ù± γ, ÐÁ FGH97 Æ Hf Ñ, γ. γ ÉÔÙÎ ½, Á Hf Ñ, ÉÔÙ ß δ Ö, 0.89%Hf, ËÎ γ Ðܾ ÑÍ, 0.3%Hf δ Ò ( 1), Á, 0.89%Hf ³ [12]. ½Î γ, Ô [14 16] ÌÇ, ÆËÌÊ Ð¹ Ú ß¼ ÄÏ, ÌÔ γ»áý Æ µ Ó. ¹, Í ³, γ» Í γ {100}«4 º Æ, Ä ÆµÍ µ γ ÎÍ, Ã Æ ¾»Á ºÆÐ µ [17]. Qiu [18] Cha [19] ² À Đ«Æ¹ ÉÔÙÍ, Þ É Ò ½ ¼ Ú À : γ {100}«º ÆÐ Ä ¼µß, Ý, 110 «Å Ö ÙÍ, Ú Í Ù ßÚÄ«³, γ {100}«Ì ÅÆ (ËÅ ), γ 100 «º ÆÐ Å, Ä Æ, Å Å γ ß, ¼ 100 Õ γ. Á ÅÆ ÑÍ, γ Å Ó,  γ Ü, 2, 4 Ë 8 Ö Ñ γ Ç. Ç Õ γ Ý Æ ÜµÐ. ³, Hf ß γ {100}«4 100 «º ÆÐ ±Å ÙÌ ÆÅ, Å» γ ÜÐ. Á Æ Hf Ñ, γ Å ÅÆ ÑÍ, Å Ä ¼ Ñß, «Â ÈÑÍ, Å Ù Ó, γ Ù. Ë ², Á Æ Hf Ñ, γ Ðܾ ÑÍ ÐÜ Ä ¼Ñß, «γ, γ, Ù²» ÆÎ Hf Å γ ßÅ, ij Ê Ç Á. 3.2 γ Ô (preferred shape) Miyazaki [20] Doi [21] º, Á Ý ÄÅ, Ý Ç ÅÆ Ê Ç Å, ¾º γ Ç»Ë 8 Í ( Ð){100}«, Ä»Ë 8 Í ( 3b). ÐÁ Æ Hf Ñ, Å Ê Ç Å ( 3b c). Á³ Þ ², ± Ù γ ÐÑ, ÎÍ ¹ ½Þ, Ä Ù. Á Ñ Ù± ±Ð», Í Ç γ, µ Í γ Ç, γ ÎÍÉÔÙÖ, Ò. Ù±, γ ÄÅ Ù ÇÈ, Õ Ç. ² Ô [14] À Ç γ ß Ä E Þ : 0.709, 0.558, Ñ Í 0.483, Í 0.436. Ë À Þ ² : γ Á Ñ Í Í Å, Ä»ÐÖ, Ú»Ñ, à µ Ê ÇÄ» Ä µ ± Õ Ç. Æ, Ñ Ù±, Ë̾º Í Ç, Á, Í Ç»Æ ÜÛ µ Õ Ç, Ô [9] Æ Ê Ç²Ò ÎÍÐÜ. ÎÑ γ Ç» ßÍ Ç, ÎÝ Û Ç,» Ý ÄÅ Æ»Û. 3.3 Æ γ Ë (coarsening) ßÎ Ì ÕÉÔÙ Ñ, γ Ç ÕÎ Ä Þ Ó. ¼Ç Ý ¾ µ ÆÑ LSW ÄÅ Ç, Ñ Ù± ±, ÁÑÙ ±Ð», Ý É Í (ÄÅ), Ö Ú²Ð. ÄÅ» ß Í Í, Ý ²Í, ¹ Ý ÄÅÉ ßÙÖ. ³, γ Þ, γ Ê Õ Ç±, Á ± ÑÙ ±Ð», γ ÇÑ, ÎÙÒ. γ Ê Ð Ç, γ Í Ç±, Ù Ê ÇÁ ѱ ±Ð», γ ÇÑ Å¾ÇÈ, Ð LSW ÄÅ Ç. Ã, ÄÈ LSW ÄÅ ±, ÂÝ Ç Õ, Ð Õ, LSW ÄÅ ÇËÌ ¹ Í Ç Ý Ë Í Ç ÄÅ (reverse coarsening). ³ ÄÅ ² 2 ÜÛ [14], Ý Ç ± (a r 0, r 0 = σ/e 1 ³ ÉÝ Ù, ÚÆ σ γ/γ

8 Ô Ò : Hf Ý Ì γ Å Å 1017 Ð, E 1 ³ ¾ ), ÄÅ»Ë Ö Ú Í, ÜĐÔ È», Ë Ð µå ÜÛ Ý Ì Ç, LSW Ç ºÄÈ. Ý Ç ³ ÉÝ Ù ± (a r 0 ), Ä Ð Ü È±, ÄÅ Ä µå ÜÛ, Ý ÄÅ, ³ Â Ç ( Ë Í Ç), Ù Ê Ç Ö (quasi equilibrium) Ç, Ý ÄÅÀ¾ÇÈ, Ñ ßÅ Õ, Ùß Ó Ñ Ì. 4 Î (1) Á FGH97 Æ Hf Ñ, Å Í Ç γ, Ç Í γ Ç, Ä γ Ê Ç, ÄŠžÇÈ. (2) Á Æ Hf Ñ, γ Ðܾ ÑÍ, ÐÜ Ä ¼Ñß, Ì Î «Î γ Å, γ, Ù» ÆÎ Hf ² Å γ Ê Ç Á. (3) Á Æ Hf Ñ, γ ÄÅ Ä µå ÜÛ, Å γ ÄÅ. ÜÞ [1] Maniar G N, Bridge J E. Metall Trans, 1971; 2: 95 [2] Muzyka D R. Met Eng Q, 1971; 11: 12 [3] Hu B F, Liu G Q, Wu K, Tian G F. Acta Metall Sin, 2012; 48: 257 (À ¹, À, Ú, Ï. ³, 2012; 48: 257) [4] Kotval P S, Venables J D, Calder R W. Metall Trans, 1972; 3: 453 [5] Duhl D N, Sullivan C P. J Met, 1971; 23: 38 [6] Dahl J M, Danesi W F, Dunn R G. Metall Trans, 1973; 4: 1087 [7] Maslenkov S B, Burova N N, Khangulov V V. Met Sci Heat Treat, 1980; 22: 283 [8] Miner R V. Metall Trans, 1977; 8A: 259 [9] Khachaturyan A G, Airapetyan V M. Phys Status Solidi, 1974; 26: 611 [10] Qiu Y Y. Acta Mater, 1996; 44: 4969 [11] Yoo Y S. Scr Mater, 2005; 53: 81 [12] Zhang Y W, Wang F M, Hu B F. Acta Metall Sin, 2012; 48: 187 (Õ Ó,, À ¹. ³, 2012; 48: 187) [13] Lifshitz I M, Slyozov V V. J Phys Chem Solids, 1961; 19: 35 [14] Khachaturyan A G, Semenovskaya S V, Morris Jr J W. Acta Metall, 1988; 36: 1563 [15] Kaufman M J, Voorhees P W, Johnson W C, Biancaniello F S. Metall Mater Trans, 1989; 20A: 2171 [16] Grosdidier T, Hazotte A, Simon A. Mater Sci Eng, 1998; A256: 183 [17] Banerjee D, Banerjee R, Wang Y. Scr Mater, 1999; 41: 1023 [18] Qiu Y Y. J Alloys Compd, 1998; 270: 145 [19] Cha P R, Yeon D H, Chung S H. Scr Mater, 2005; 52: 1241 [20] Miyazaki T, Imamura H, Kozakai T. Mater Sci Eng, 1982; 54: 9 [21] Doi M, Miyazaki T, Wakatsuki T. Mater Sci Eng, 1984; 67: 247 ( : )