46 À 12 Vol.46 No.12 2010 12 1495 1500 ACTA METALLURGICA SINICA Dec. 2010 pp.1495 1500  Al Al 4 C ³ Mg ÇÅ Ë ÍÎÉ Ï ÊÌ ( ÑØ»Ó ËÂÝ ÐÜ, 110819) ± Al Al 4 C ÁÓÅ Ð Ã, Mg  ¹. Ö Ð² 1.0%Al Al 4 C ÁÓÅ ÁÓ É, α Mg ³ÄÇ 106 µm. Mg  ±, Ö Á 600 W Á Ó É. Þ, ÎÓ µæ ßÌ «, ÎÓ ßµÖ Ý Â ß ÑÜÁ É µæ, ß, ÌÃ»Ò «. µ Al Al 4 C ÁÓű«² Mg  ÌÃ, Ë ÆÔÁÓ. ¹Ð ß ÚÓ «., Mg, Al 4 C, ÁÓ Æ»² TG146.2 ¾ A à ² 0412 1961(2010)12 1495 06 EFFECTS OF Al Al 4 C REFINER AND ULTRASONIC FIELD ON MICROSTRUCTURES OF PURE Mg GAO Shengyuan, LE Qichi, ZHANG Zhiqiang, CUI Jianzhong Key Laboratory of Electromagnetic Processing of Materials, Ministry of Education, Northeastern University, Shenyang 110819 Correspondent: CUI Jianzhong, professor, Tel: (024)868178, E-mail: jzcui@mail.neu.edu.cn Supported by National Basic Research Program of China (Nos.2007CB61701 and 2007CB61702) and National Natural Science Foundation of China (Nos.50904018, 5097407 and 5100402) Manuscript received 2010 05 1, in revised form 2010 08 04 ABSTRACT The melt of pure Mg was inoculated at the conditions of different addition amounts of Al Al 4 C refiner. When adding 1.0%Al Al 4 C refiner, the refining effect is the best and the average grain size of α Mg is reduced from millimeter level to 106 µm. Ultrasound fields with different power levels were applied on the melt of pure magnesium and the best refining effect was obtained when the power was 600 W. The results show that the undercooling formed by breakdown of cavitation bubbles may have a promoting effect to nucleate. The breakdown of cavitation bubbles and the agitations of acoustic stream on the melt cause the fragmentation of fine dendritic crystal which could form new crystallization nuclei, this process plays the main role for nucleating in the melt. The combined application of ultrasound and Al Al 4 C refiner to the melt of pure Mg could significantly refine its grain. The mechanism would be an the activation effect of ultrasound on the impurities in the melt. KEY WORDS ultrasound field, pure Mg, Al 4 C, grain refinement Mg Ú ½Õ Å, Õ Mg hcp Â Ò Ñ ². ÂÔ Mg Ì ÇÕ º ÚÑ [1,2]. Mg ÂÔ * È ß Þ ÑÎ 2007CB61701 2007CB- 61702, È ÊÙ߾Π50904018, 5097407 5100402, ß ÊÞÅ ±ÜÎ ¾Î 90409002 90209002, ±¹¹ ØÆ Ó ¾ËÅ ÑÎ NCET 08 0098 ȳ ÊÙ߾Π20100471648 ßÙË Á : 2010 05 1, ßÙÒ¾ Á : 2010 08 04 :,, 198, ³ DOI: 10.724/SP.J.107.2010.0020 Ó Í Ã«À» º. º, ³Í ÓÒ Ô ¾Ñ, Ò Ñ Æ, Ì Í [,4] ; À ², ÐÈÓ Æ. ëÆ, Đ, ÂÔ Ê, À Mg Al ÅÓ ÂÔ Đ [5,6]. Ú Ç ÂÔ«ÀÓÑ Ë Al 4 C, Đ. Al 4 C α Mg Å hcp, α Mg (a=0.2088 nm, c=0.52017 nm) Al 4 C
1496 ½ Ð 46 À (a=0.88 nm, c=0.49900 nm) ³. Bramfitt [7] Î, Å, δ <6% Å, δ ¼³ 6% 15% Ý, δ >15%. Bramfitt [7] à «ÌÌ, (10 10) Mg /(10 10) Al4 C Å Ã.5%, Ì, Al 4 C Ì Ì α Mg Ë Â Ô. ºÂÔ ¼ Ú Ã ÏÔ Þ ÚÂÔ, º ÚµØ Ö ½Õ À. ÏÔ Ú ²»ÜË, Ú, ÀÏÔ. Ü ÚÆ, ¾ Û, Ù ²ÇÜË, À ÏÔ Ý, Ò ÏÔ ½ Ï Ü. Eskin [8,9] ÏÔ ÛÔÒÃ, ÒÃ. [10], Đ ÇÜË Ü ÏÔ ÉÞ²ÒÝà Í, Ò Đ. Þ Ú, ³ ² Ñ Ð, ÉÂ Ò ¾ ÆÓ ÀÆ Ü, ¼ Þ. ¼ ÒÆ Å º µ 0. ¼ Þ ²Ó, Ò Þ ²Ó, Ì Þ Þ 10 100. Komarov [11] ÏÔ Þ Ð Ê ÞÁÇÃ,., À 2 ³ ݲ Mg Å Û. ÍÑ Al Al 4 C ÂÔ«Mg Ð, ³ È ÒÀ 2 ÂÔ Mg Ú Í, ß Ò 2 ² Ä ÂÔ Ê, ËÁÂÔ. 1 Al ( 50 µm, 99.8%) ( 50 µm, 99.6%), ÔÚ Ñ Ð, À Al Al 4 C ÂÔ«, «Mg ( 99.50%) ÂÔ. º ³ Æ ß Ã, SF 6 +CO 2 Ù¾ Æ. Al Al 4 C ÂÔ«ÇÑ (ѳ ) ³ 0.%, 0.6% 1.0%. 680 Æ Æ, à ÜÇ Al Al 4 C ÂÔ«Ã Å, ² ÛÒ 1.0% (ѳ ) Al Mg Ú «. Æ 10 min à Ç, Ú«º Ð Ã. ÃĐ Ã ÂÅÃ Þ ³ g Å +50 ml +5 ml ÄÛ +2.5 ml Å 6.5 g Å +100 ml + 10 ml ÄÛ +5 ml Å Ð Í. Leica DMR Ëǽ (OM) OLYMPUS SZX16 ÕÇ ½ (OM) ÐÃ, Ê ºØ Image tool È È Ð³, Al Al 4 C ÂÔ Ðß. ÐĐÞ Æµ 1 Ö. ÐĐ½Õ «Mg. ²Đ (20±2) khz, ½ Đ 0 2 kw ÕÌÅ. Đŵ ±10 W. 680 Ä ÐÐ Đ, ³ ß Òµ² Â Đ Õ É Mg ÂÔ Ê. Å Þ ( ) Þ (Ð ) À г. 1 Ý Fig.1 Schematic diagram of the experiment arrangement of ultrasonic treatment 2 ¹± µ 2 Mg ǵ²Ñ Al Al 4 C ÂÔ«OM. µì, Ç Al Al 4 C, Mg À Ô ÆÇ Ñ, Öß (µ 2a). Mg Ç Al Al 4 C, ºÚ ÒÆÇ, Ð ÇÑ µ, Ñ Â (µ 2b d), Ç 1.0% Al Al 4 C,  Å, ½Æ Ô, Å È 106 µm (µ 2d). Ç 1.0% Al, Mg ÂÔ, Õ Çѳ 1.0% Al Al 4 C ÂÔ«Mg (µ 2d) ², Ê, Ó, ŠѲ (µ 2e). µ Mg à ËÊ Ì 10 µ² Đ OM. µì, Ð, Mg Ô ÆÇ Ñ, Öß, Ä Â (µ a).  Р450 W, Öß ÆÓÃ, ÂÔ, ÕÅ Ñ ² (µ b).  Р600 W, Öß ÓÑÃ, Æ ÂÔ (µ c).  Р1000 W, Öß ÆÓ Ó, Õ À  (µ d). µ 4 Õ É Å Mg à OM. Mg, À ÁÈ Ú É Å (µ 4a). Mg à 800 W Õ 1 min ÆÇ Ñ, Ú«( ) º (µ 4b). Mg à 986 W É 1 min Ñ Õ.
12 + 5\} : Al Al C Hn _A\; Mg Vz T 4 1497 (% Al Al C l{^ Mg u W <2 4 Fig.2 As cast microstructures of pure Mg (a), and to which 0.%Al Al4 C (b), 0.6%Al Al4 C (c), 1.0%Al Al4 C (d) and 1.0%Al (e) added (%di>~k{^ Mg G W < Fig. Microstructures of pure Mg after being processed by ultrasound of 0 W (a), 450 W (b), 600 W (c) and 1000 W (d).8hj, M7m&8 () 4c). _ Mg K ;~ # 1 min i > # 4. =+ 8h J, q # 4 > Y # Yr{8 o () 4d). ) 5 4_ Mg K e O 1.0%Al Al C Jp # 4 e j q C ^ OM X. > 680 h _ Mg 8h <' 1N, J M 7 () 5a). _ Mg > 710 Le? 4 88 W j q C ^ # O 1.0%Al Al4 C J p i, X 5Æ+Jp, `HomJ 8h, qm7m&8 () 5b).
1 } s 1498 <4 46 H (%Ya"pK^ Mg G WfJE$ Fig.4 Microstructures of pure Mg (a), after being processed by 800 W continuous ultrasound for 1 min (b), by 986 W impulse ultrasound for 1 min (c) and by mechanical rabbling for 1 min (d) <5 B )Io % K^ Mg G WfJE$ Fig.5 Microstructures of pure Mg to which 1.0%Al Al4 C added after being processed by ultrasound at 608 (a) and by 88 W continuous ultrasound at 710.1 ">91 Al Al4 C Mg ) F Es 4 [12] X Es = El T k El = EF XZ α qe, Es 4 ; El 4 l 9 9 9 ; E 4 m,. 0 >>?95Z; nαl 4 l 9 α Ow. EF 4 Fermi, T$ULqA : (1) Z= EF XhX Z l Enαl (E)dE (2) α nαl (E)dE i () qe, Z 4F'e $0 >Df{ h.
12 Ð : Al Al 4 C ÀÒ Mg ÎÞ Ì 1499 ¼Đ E b E b = E s E self (4) Õ, E self «ÈÐ ¼Đ Ñ. «Î α Mg Al 4 C ¼Đ ³ 84.8750 117.6057 ev, Ì Al 4 C ¼Đ Đ³Ë α Mg Ë. ¼Đ Ú ³ ¼Đ Ñ Í, ¼Đ À ¼Đ ¼Đ ËÐ ¼ Ñ. ÍмĐ, Đ (à Ó) Õ À»¹Ô ÑÓ, µå º, (à ) Ø ¼Đ Å. ³ Al 4 C ¼Đ Đ³Ë α Mg Ë, Ñà Ç, Al 4 C à Ñ, Mg À, Al 4 C Mg à ÓÑ Ñ. Mg À Öß, Ä, Ç 1.0%Al Al 4 C ÂÔ«, ³º Î ÓÑ Al 4 C, ÍÄ, Ó Đ, Ò ÆÇÂÔ. Al Ó», ÍÀ Ä Ô À ÎË, Mg à ² ÂÔ. ²Ò Ç 1.0% Al «Mg À (µ 2e). α Mg ÂÔ, ÕÊ, ÀÅ, Ì, Ç 1.0%Al Al 4 C ÂÔ«, Mg ÂÔÚ 106 µm..2 Mg µ Yasuda [1] ÎÏÔ ¾, Komarov [11] ÎÏÔ Þ Ð Ê ±Ø. ÐĐ Komarov [11] ÂÔ Å Ì. Ƶ b Ö, Öß ÒÍÑ Â, ÀÚ ³ Ä, Þ Ã À Þ. Þ É Ð (É Ã ) À À Ê, Ê ±À, Òà Đ; ² Þ À Ö ÔÚà º, Òà Đ. µ c Æ ÈÐÒÀÆ Û. Ð Đ, ¼, ÏÔ Ø, À Mg ÜÝÒ Ã º Ó Í, ² Þ Ã Ø, Ú ÅÌ. ³  ¼, ¼ À À, ÎÎ, ÃÔ, Ó À. Đ Æ Ó, Ó Ù (µ d), ÀÚ Mg ÀÍÄ, Í ¹Ø À ³ Đ Í ± ÃÔ, Ó, ÂÔ Ê Í.. Ä Mg µ [14,15], Ã, ÏÔ ÉÞ² É ÒÓ, ÀÓÑ, Ò Ô ÂÔ. Õµ 4 ÐĐÈ ÏÔ Û. Å Mg ˲, À Æ ÐĐÍÄ, Å Ã ÅË ³, ¼Ú º Í, Ò Ú«º º, À È Ì ÝÚ Û. Ó ÚÊ Ã ¹, ³, Ô ÓÑ Ñ Ê º Ã, ÏÔ Ü ³ ½ º, º Ê ÒÓÑÓ Ê Ã. ÀÓÑ Ò Ô Â Ô. ² Þ Ì Ã Þ, ³Æ Â Ê Ð Ã, À., Öß «ÍÑ ÎÈ, ÀÌ Ê Ã Ð ² ÎÎ, Å Ü Ð ¾ (µ 4b). Å Ð, À  Š¹ ³Ú«º, Ú«º ÀÒÍÑ Â (µ 4d). ÌÌÌ, ³Ã, Þ Å Ä, Â Ê Ð ÎÎ, ³ ³Ã, À Öß ¾  Ð. ÏÔ Ü ÒÊ Ã, ³ ÂÔ Ôµ¼Ó..4 Á Al Al 4 C ÈÀ µ ¼ Eskin [9] ÛÔÀ Û Đ ÂÔ«² ÐĐÈ, Ì Æ Ð ÍÌ ØÎÈÓÑ Â (µ 5b). À¼, À ÛÔ ½, À, ÜÝ Â. µ 5b Ì ÇÎ, ÓÑ ³ ³Ë È ²Ó ¾, È ²Ó Å Å. À Ó,, À ÃÆ, ³ Al Al 4 C ÂÔ«Î ÓÑ Ã Al 4 C, Ë ³ ÛÔ, Mg Ã Ç À ÃÆ, ÓÑ Ë Al 4 C, Ó Đ, ÀÓÑ Ð. ÀƳ, µ 5b È ²Ó ¾ÐÓÑÂ È Ì ÝÚ Û. Đ³ Ç, ÂÔ«, Đ³ 0.95%, ÂÔ«², Đ³ 2.07%, Ì ÈÆ, à Al 4 C ¼ÚÛÔ, µ 6. Ú», ³ Mg Ã, Þ Þ ÏÔ Al 4 C Æ, Ï ¼Ð C É, ÒÝ Al 4 C,, Ò Mg ¼Đ ³ Al 4 C, Đ, ÓÓ Al 4 C Đ, À. ² Þ À À Ô Ú ² à º,,
1500 ½ Ð 46 À  Đ,, Ô Ù. () Al Al 4 C ÂÔ«² ³ Mg Ã, Ì ÇÕÂÔ. ÛÔ, ÓÑ Al 4 C Ç À, À Ë, Ó Đ. º 6 ÁÓÅ µáó屫ã Mg Ïß SEM Ï Fig.6 SEM images of pure Mg to which only 1.0%Al Al 4 C refiner added (a) and 1.0%Al Al 4 C refiner added after being processed by ultrasound of 88 W (b) Ó. 4 ¹½ (1) Mg Ã Ç 1.0%Al Al 4 C (ѳ ) ÂÔ«Ì ÂÔ α Mg, ÅÈ 106 µm. (2) Đ Ì ÂÔ Mg. ÏÔ Í, ÏÔ Þ Ã ÒÝ Ê, À, ÀÆÍÄ ¼Ó.  Р600 W ÂÔ ÊÅ, [1] Kojima Y. Mater Sci Forum, 2000; 50 51: [2] Watanabe H, Tsutsui H, Mukai T, Ishikawa K, Okanda Y, Kohzu M, Hiqashi K. Mater Sci Forum, 2000; 50 51: 171 [] Yang M B, Pan F S, Li Z S. Foundry, 2005; 54: 14 ( ±, º,. Ù, 2005; 54: 14) [4] Avedesian M M, Baker H. Magnesium and Magnesium Alloys. Materials Park, Ohio: ASM Int, 1999: 5 [5] Mukai T, Watanabe H, Higashi K. Mater Sci Forum, 2000; 50 51: 159 [6] Tamura Y, Kono N, Motegi T, Sato E. J Jpn Inst Light Met, 1998; 48(4): 185 [7] Bramfitt B L. Metall Trans, 1970; 1: 1987 [8] Eskin G I. Ultrasonic Treatment of Light Alloy Melts. Amsterdam: Gordon and Breach, 1998: 114 [9] Eskin G I. Ultrason Sonochem, 2001; 8: 19 [10] Chen F. PhD Thesis, Southeast University, NanJing, 1991 ( µ. Æ ÒÙ³ Ù,, 1991) [11] Komarov S V, Kuwabara M, Abramov O V. ISIJ Int, 2005; 45: l765 [12] Xiao S X, Wang C Y, Chen T L. The Application of the Discrete Variational Method in the Density Functional Theory to Chemistry and Materials Physics. Beijing : Science Press, 1998: 92 ( Ò, ¼Ê,. Å Ï ß Ê ² ÓÙ ¼Ô Ù ß. : ÊÙÍ Ï, 1998: 92) [1] Yasuda K, Saiki Y, Kubo T, Kuwabara M, Yang J. Jpn J Appl Phys, 2007; 46: 499 [14] Campbell J. Int Metall Rev, 1981; 26: 71 [15] Schaefer R J, Glicksman M B. Trans AIME, 1967; 29: 257