SOLIDIFICATION BEHAVIOR AND GRAIN SIZE OF SAND CASTING Mg-6Al-xZn ALLOYS

doi:10.3724/SP.J.1037.2013.00558

Acta Metall Sin

2014, Vol. 50

Issue (5): 601-609 DOI: 10.3724/SP.J.1037.2013.00558

Current Issue | Archive | Adv Search

SOLIDIFICATION BEHAVIOR AND GRAIN SIZE OF SAND CASTING Mg-6Al-xZn ALLOYS

HOU Danhui^1,², LIANG Songmao³, CHEN Rongshi²(

), DONG Chuang¹

1 Institute of Material Science and Engineering, Dalian University of Techonlogy, Dalian 116024
2 Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016
3 Institute of Metallurgy, Clausthal University of Technology, Clausthal-Zellerfeld, Germany, 38678

Cite this article:

HOU Danhui, LIANG Songmao, CHEN Rongshi, DONG Chuang. SOLIDIFICATION BEHAVIOR AND GRAIN SIZE OF SAND CASTING Mg-6Al-xZn ALLOYS. Acta Metall Sin, 2014, 50(5): 601-609.

Download:

HTML

PDF(9805KB)
Export: BibTeX | EndNote (RIS)

Abstract

The solidification behavior and microstructure evolution of sand cast Mg-6Al-xZn alloy (named as AZ6x alloys, x=0, 2, 4, 6, mass fraction, %) were characterized by two-thermocouple thermal analysis technology and SEM. The grain sizes of the alloys were quantitatively determined by EBSD technology. Thermodynamic calculations were applied in Pandat software for phase diagram calculation, Scheil model solidification simulation and growth restriction factor values (GRF or values). The results show that solidification of AZ6x alloys follows non-equilibrium solidification paths. Besides the γ-Mg₁₇Al₁₂ phase, which is the only secondary phase in AZ60 alloy, another Φ-Mg₂₁(Al, Zn)₁₇ phase appears in the as-cast microstructure of AZ62 to AZ66 alloys. With the increase of the Zn content, the amount of γ-Mg₁₇Al₁₂ phase decreases and while increase the amount of Φ-Mg₂₁(Al, Zn)₁₇phase. Calculated equilibrium phase diagram shows that in the AZ60~AZ64 alloys both γ-Mg₁₇Al₁₂ phase and Φ-Mg₂₁(Al, Zn)₁₇ phase can be dissolved into α-Mg under proper heat treatment conditions. However, Φ-Mg₂₁(Al, Zn)₁₇ phase in AZ66 alloy can not be completely dissolved into a-Mg for any temperature. The results also indicate that higher Zn content alloys have higher values and smaller grain size, and lower solid fraction at dendrite coherency point (?_s^DCP). The relationship of values, grain size and ?_s^DCP has been also discussed.

Key words: Mg-Al-Zn alloy sand casting grain size growth restriction factor solid fraction at dendrite coherency point

Received: 05 September 2013

ZTFLH:

TG146.2

Fund: National Basic Research Program of China (No.2013CB632202) and National Natural Science Foundation of China ( Nos.51105350 and 51301173)

About author: null

侯丹辉, 男, 1982年生, 博士生

	Service

	E-mail this article
	Add to citation manager
	E-mail Alert
	RSS
	（）
	Articles by authors
	Danhui HOU
	Songmao LIANG
	Rongshi CHEN
	Chuang DONG

URL:

https://www.ams.org.cn/EN/10.3724/SP.J.1037.2013.00558 OR https://www.ams.org.cn/EN/Y2014/V50/I5/601

Table 1 Chemical composition of alloys(mass fraction / %)

Fig.1 Schematic diagram of two-thermocouple thermal analysis system (unit: mm) (a) and determination of dendritic coherency point through two-thermocouple thermal analysis (b) (T_DCP—dendrite coherency temperature of the alloys, T_c—center thermocouple temperature, T_w—wall thermocouple temperature)

Fig.2 Thermal analysis results (a, c, e, g) and corresponding as-cast microstructures (b, d, f, h) of alloys AZ60 (a, b), AZ62 (c, d), AZ64 (e, f) and AZ66 (g, h) (T_onset—the temperature of start nucleation, T_peak—the temperature of finish nucleation)

Fig.3 Comparison of the calculation vertical section of Mg-5.76Al -0.24Mn-xZn with phase transition temperature obtained by thermal analysis results of AZ6x alloys

Table 2 Critical points temperature obtained from the cooling curves of the central thermocouple

Fig.4 Solidification curves of AZ6x alloys obtained by Scheil calculation and thermal analysis

Fig.5 EBSD maps of alloy AZ60 with average grain size of 557 μm (a), alloy AZ62 with average grain size of 275 μm (b), alloy AZ64 with average grain size of 271 μm (c) and alloy AZ66 with average grain size of 235 μm (d)

Fig.6 Thermal analysis results of alloys AZ60 (a), AZ62 (b) AZ64 (c) and AZ66 (d)

Fig.7 Effect of Zn content on the value of ?_s^DCP

Alloy	Average grain size / μm	$Q$	f_s^DCP-Scheil / %	f_s^DCP-TA / %
AZ60	557	21	36	35
AZ62	275	28	27	27
AZ64	271	34	31	26
AZ66	235	43	23	25

Table 3 Average grain size, grow restriction factor (Q value) and solid fraction at dendrite coherency point ?_s^DCP ofAZ6x alloys

Fig.8 Dendritic morphology diagrams with low (a) and high (b) solute contents

[1]	Luo A A. J Magnesium Alloys, 2013; 1: 2
[2]	Ma Y Q, Chen R S, Han E H. Mater Lett, 2007; 61: 2527
[3]	Maxwell I, Hellawell A. Acta Metall, 1975; 23: 229
[4]	Greer A L, Bunn A M, Tronche A, Evans P V, Bristow D J. Acta Mater, 2000; 48: 2823
[5]	St John D H, Qian M, Easton M A, Cao P, Hildebrand Z. Metall Mater Trans, 2005; 36A: 1669
[6]	Schmid-Fetzer R, Kozlov A. Acta Mater, 2011; 59: 6133
[7]	Veldman N L M, Dahle A K, St John D H, Arnberg L. Metall Mater Trans, 2001; 32A: 147
[8]	Liang S M, Chen R S, Blandin J J, Suery M, Han E H. Mater Sci Eng, 2008; A480: 365
[9]	Arnberg L, Chai G, Backerud L. Mater Sci Eng, 1993; A173: 101
[10]	Dahle A K, Arnberg L. Mater Sci Eng, 1997; A225: 38
[11]	Chai G, Bäckerud L, RØlland T, Arnberg L. Metall Mater Trans, 1995; 26A: 965
[12]	Malekan M, Shabestari S G. Metall Mater Trans, 2009; 40A: 3196
[13]	Liang S M. PhD Dissertation, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 2009
	(梁松茂. 中国科学院金属研究所博士学位论文, 沈阳, 2009)
[14]	Bäckerud L, Krol E, Tamminen J. Solidification Characteristics of Aluminium Alloys. Vol.1, Oslo: Skan Aluminium, 1986: 65
[15]	Chang H W, Qiu D, Taylor J A, Easton M A, Zhang M X. J Magnesium Alloys, 2013; 1: 115
[16]	Kierkus W T, Solokowski J H. AFS Trans, 1999; 107: 161
[17]	Cao W, Chen S L, Zhang F, Wu K, Yang Y, Chang Y A, Schmid-Fetzer R, Oates W A. Calphad, 2009; 33: 328
[18]	Liang P, Tarfa T, Robinson J A, Wagner S, Ochin P, Harmelin M G, Seifert H J, Lukas H L, Aldinger F. Thermochim Acta, 1998; 314: 87
[19]	Ohno M, Schmid-Fetzer R. Z Metallkd, 2005; 96: 857
[20]	Ohno M, Mirković D, Schmid-Fetzer R. Mater Sci Eng, 2006; A421: 328
[21]	Ohno M, Schmid-Fetzer R. Int J Mater Res, 2006; 97: 526
[22]	Ohno M, Mirković D, Schmid-Fetzer R. Acta Mater, 2006; 54: 3883
[23]	Thorvaldsen A, Aliravci C A. In: Proc International Symposium, Montreal, Canada: Metallurgical of CIM, 1992: 277
[24]	Tamura Y, Yagi J, Haitani T, Motegi T, Kono N, Tamehiro H, Saito H. Mater Trans, 2003; 44: 552
[25]	Liang S M, Ma Y Q, Chen R S, Han E H. Mater Trans, 2008; 49: 986

[1]	LI Fulin, FU Rui, BAI Yunrui, MENG Lingchao, TAN Haibing, ZHONG Yan, TIAN Wei, DU Jinhui, TIAN Zhiling. Effects of Initial Grain Size and Strengthening Phase on Thermal Deformation and Recrystallization Behavior of GH4096 Superalloy[J]. 金属学报, 2023, 59(7): 855-870.
[2]	YUAN Jiahua, ZHANG Qiuhong, WANG Jinliang, WANG Lingyu, WANG Chenchong, XU Wei. Synergistic Effect of Magnetic Field and Grain Size on Martensite Nucleation and Variant Selection[J]. 金属学报, 2022, 58(12): 1570-1580.
[3]	ZHANG Shouqing, HU Xiaofeng, DU Yubin, JIANG Haichang, PANG Huiyong, RONG Lijian. Cross-Section Effect of Ni-Cr-Mo-B Ultra-Heavy Steel Plate for Offshore Platform[J]. 金属学报, 2020, 56(9): 1227-1238.
[4]	XU Zhanyi, SHA Yuhui, ZHANG Fang, ZHANG Huabing, LI Guobao, CHU Shuangjie, ZUO Liang. Orientation Selection Behavior During Secondary Recrystallization in Grain-Oriented Silicon Steel[J]. 金属学报, 2020, 56(8): 1067-1074.
[5]	HE Shuwen, WANG Minghua, BAI Qin, XIA Shuang, ZHOU Bangxin. Effect of TaC Content on Microstructure and Mechanical Properties of WC-TiC-TaC-Co Cemented Carbide[J]. 金属学报, 2020, 56(7): 1015-1024.
[6]	HUA Hanyu,XIE Jun,SHU Delong,HOU Guichen,Naicheng SHENG,YU Jinjiang,CUI Chuanyong,SUN Xiaofeng,ZHOU Yizhou. Influence of W Content on the Microstructure of Nickel Base Superalloy with High W Content[J]. 金属学报, 2020, 56(2): 161-170.
[7]	Xin LI,Yuecheng DONG,Zhenhua DAN,Hui CHANG,Zhigang FANG,Yanhua GUO. Corrosion Behavior of Ultrafine Grained Pure Ti Processed by Equal Channel Angular Pressing[J]. 金属学报, 2019, 55(8): 967-975.
[8]	Yi MEI, Quanlong SUN, Lihua YU, Chuanrong WANG, Huaqiang XIAO. Grain Size Prediction of Aluminum Alloy Dies Castings Based on GA-ELM[J]. 金属学报, 2017, 53(9): 1125-1132.
[9]	Ming ZHANG, Guoquan LIU, Benfu HU. Effect of Microstructure Instability on Hot Plasticity During Thermomechanical Processing in PM Nickel-Based Superalloy[J]. 金属学报, 2017, 53(11): 1469-1477.
[10]	Quan FU,Yuhui SHA,Zhenghua HE,Fan LEI,Fang ZHANG,Liang ZUO. Recrystallization Texture and Magnetostriction in Binary Fe₈₁Ga₁₉ Sheets[J]. 金属学报, 2017, 53(1): 90-96.
[11]	Yongfeng SONG, Xiongbing LI, Haiping WU, Jiayong SI, Xiaoqin HAN. EFFECTS OF IN718 GRAIN SIZE ON ULTRASONICBACKSCATTING SIGNALS AND ITS NONDE-STRUCTIVE EVALUATION METHOD[J]. 金属学报, 2016, 52(3): 378-384.
[12]	Jin LIU,Guohui ZHU. MODEL OF THE EFFECT OF GRAIN SIZE ON PLASTI-CITY IN ULTRA-FINE GRAIN SIZE STEELS[J]. 金属学报, 2015, 51(7): 777-783.
[13]	Qing ZHAO,Shuang XIA,Bangxin ZHOU,Qin BAI,Cheng SU,Baoshun WANG,Zhigang CAI. EFFECT OF DEFORMATION AND THERMOMECHA- NICAL PROCESSING ON GRAIN BOUNDARY CHARACTER DISTRIBUTION OF ALLOY 825 TUBES[J]. 金属学报, 2015, 51(12): 1465-1471.
[14]	LI Xiongbing, SONG Yongfeng, NI Peijun, LIU Feng. ULTRASONIC EVALUATION METHOD FOR GRAIN SIZE BASED ON MULTI-SCALE ATTENUATION[J]. 金属学报, 2015, 51(1): 121-128.
[15]	WU Huibin, WU Fengjuan, YANG Shanwu, TANG Di. THE FORMATION MECHANISM OF AUSTENITE STRUCTURE WITH MICRO/SUB-MICROMETER BIMODAL GRAIN SIZE DISTRIBUTION[J]. 金属学报, 2014, 50(3): 269-274.

No Suggested Reading articles found!

Viewed

Full text

Abstract

Cited

Shared

Discussed