Effects of processing parameters and addition of flame-retardant into moulding sand on the microstructure and fluidity of sand-cast magnesium alloy Mg-10Gd-3Y-0.5Zr

doi:10.1016/j.jmst.2017.01.013

Abstract

Abstract:

In this study, the effects of processing parameters (such as pouring temperature and mould pre-heating temperature) and flame-retardant content on the microstructure and fluidity of sand-cast magnesium (Mg) alloy Mg-10Gd-3Y-0.5Zr (GW103K) were systematically investigated. It was found that the increase of pouring temperature leads to coarsened microstructure and decreased fluidity of sand-cast GW103K alloy. Increase of mould pre-heating temperature incurs coarsening of as-cast microstructure and increase of fluidity. The addition of flame-retardant into moulding sand has a negligible influence on the microstructure of sand-cast GW103K alloy. With the increase in flame-retardant content, fluidity of the alloy initially increases and then decreases. The optimized process parameters and flame-retardant addition were obtained to be pouring temperature of 750 °C, mould temperature of 110 °C, and flame-retardant addition of 1%. The fire retardant mechanism of moulding sand was determined.

Key words: Magnesium alloy, Fluidity, Microstructure, Flame retardant, Fire retardant mechanism

Li Yanlei, Wu Guohua, Chen Antao, Liu Wencai, Wang Yingxin, Zhang Liang. Effects of processing parameters and addition of flame-retardant into moulding sand on the microstructure and fluidity of sand-cast magnesium alloy Mg-10Gd-3Y-0.5Zr[J]. J. Mater. Sci. Technol., 2017, 33(6): 558-566.

Figures/Tables 15

Table 1 Actual chemical composition of Mg-10Gd-3Y-0.5Zr alloy in this work (wt%).

Element	Gd	Y	Zr	Mg
wt%	9.85	3.26	0.48	Bal.

Fig. 1. Schematic of the preparation of fluidity samples by no-bake furan resin mould: (a) sand mould, and (b) spiral casting.

Table 2 Fluidity test parameters varied in this work.

Part	Flame-retardant content (wt%)	Pouring temperature (°C)	Mould pre-heating temperature (°C)
1	1	720/750/780	70
	0	720/750/780
2	1	750	40/110
	0		40/110
	0
	0.5
3	1	750	70
	1.5
	2

Fig. 2. XRD analysis of the as-cast Mg-10Gd-3Y-0.5Zr alloy.

Fig. 3. Optical microstructures of Mg-10Gd-3Y-0.5Zr alloy at different pouring temperatures and no addition of flame retardant into moulding sand: (a) 720 °C, (b) 750 °C, (c) 780 °C, and (d) variations in grain size as a function of pouring temperature.

Fig. 4. Fluidity lengths of as-cast Mg-10Gd-3Y-0.5Zr alloy at different pouring temperatures.

Fig. 5. Identification of typical oxide inclusion phases in as-cast Mg-10Gd-3Y-0.5Zr alloy by SEM-EDS: (a) SEM image of the Mg-10Gd-3Y-0.5Zr alloy prepared at 1.5% flame-retardant addition in moulding sand, (b) magnified view of the box region in (a), (c) EDS spectrum of a polygonal particle (labeled as “1” in (b)).

Table 3 Oxide inclusions content of as-cast Mg-10Gd-3Y-0.5Zr alloy under different conditions.

Oxide inclusions content (vol.%)	Pouring temperature (°C)			Mould pre-heating temperature (°C)			Flame retardant content (%)
	720	750	780	40	70	110	0.5	1	1.5	2
Flame-retardant	0.43	0.42	0.73	0.28	0.42	0.45	0.46	0.38	0.42	0.35
No added	0.52	0.68	0.83	0.35	0.68	0.48

Fig. 6. Optical micrographs showing grain structure in Mg-10Gd-3Y-0.5Zr alloy at different preheating sand moulding temperatures: (a) 40 °C, (b) 70 °C, (c) 110 °C, and (d) variation in grain size as a function of mould pre-heating temperature.

Fig. 7. Fluidity lengths of as-cast Mg-10Gd-3Y-0.5Zr alloy at different preheating temperatures of the mould.

Fig. 8. Optical microstructures of Mg-10Gd-3Y-0.5Zr alloy at different flame retardant addition levels: (a) 0%, (b) 0.5%, (c) 1%, (d) 1.5%, (e) 2%, and (f) variation in grain size as a function of flame retardant content.

Fig. 9. Fluidity lengths of as-cast Mg-10Gd-3Y-0.5Zr alloy at different flame retardant addition levels.

Fig. 10. TG/DTG profiles for the combustion of flame retardant filled moulding sand.

Fig. 11. FTIR spectrograms for gaseous products during combustion of furan resin sand (a) combustion at 226 °C, (b) combustion at 517 °C, and (c) combustion at 700 °C.

Fig. 12. (a) Variation in gas evolution of moulding sand as a function of the flame-retardant addition level, and (b) variation in air permeability of moulding sand as a function of the flame retardant addition level.

References

[1]	B.L. Mordike, T. EbertMater.Sci. Eng. A, 302(2001), pp. 37-45
[2]	A.A. Luo, J. MagnAlloy, 1(2013), pp. 2-22
[3]	J.F. Nie, B.C.MuddleScr. Mater., 40(1999), pp. 1089-1094
[4]	Y.L. Mu, Q.D. Wang, M.L. Hu, V. Janik, D.D.YinScr. Mater., 68(2013), pp. 885-888
[5]	S.M. He, X.Q. Zeng, L.M. Peng, X. Gao, J.F.NieJ. Alloys Compd., 42(2006), pp. 309-313
[6]	S.M. He, X.Q. Zeng, L.M. Peng, M.X. Gao, J.F. Nie, W.J.DingJ. Alloys Compd., 427(2007), pp. 316-323
[7]	V.D. Janik, D. Yin, Y.D. Wang, S.M. He, C.J. Chen, Z. Chen, C.J.BoehlertMater. Sci. Eng. A, 528(2011), pp. 3105-3112
[8]	I.A. Anyanwu, S. Kamado, Y. KojimaMater.Trans., 42(2001), pp. 1206-1211
[9]	M.B. Yang, F.S.PanMater. Des., 31(2010), pp. 68-75
[10]	Y. TurenMater.Des., 49(2013), pp. 1009-1015
[11]	Q. Hua, D.M. Gao, H.J. Zhang, Y.H. Zhang, Q.J.ZhaiMater. Sci. Eng. A, 444(2007), pp. 69-74
[12]	Q.D. Wang, Y.Z. Lu, X.Q. Zeng, W.J. Ding, Y.P. Zhu, Q.H. Li, J. LanMater.Sci. Eng. A, 271(1999), pp. 109-115
[13]	T. Rzychoń, A. KielbusArch.Mater. Sci. Eng., 28(2007), pp. 601-604
[14]	W. Wang, Y.G. Huang, G.H. Wu, Q.D. Wang, M. Sun, W.J.DingJ. Alloys Compd., 480(2009), pp. 386-391
[15]	Y. Chen, J.X. Luo, J. Du, D.F.ChenChina Foundry, 11(2014), pp. 115-118
[16]	C.S. Goh, K.S. Soh, P.H. Oon, B.W.ChuaMater. Des., 31(2010), pp. S50-S53
[17]	X.F. Wang, S.M.XiongJ. Mater.Sci. Technol., 30(2014), pp. 353-358
[18]	G. Pettersen, E. ?vrelid, G. Tranell, J. Fenstad, H. GjestlandMater.Sci. Eng. A, 332(2002), pp. 285-294
[19]	H.K. Chen, J.R. Liu, W.D.HuangMater. Charact., 58(2007), pp. 51-58
[20]	L. Zhao, J.R. Liu, H.K. Chen, W.D.HuangJ. Alloys Compd., 480(2009), pp. 711-716
[21]	S.P. Cashion, N.J. Ricketts, P.C.HayesJ. Light Met., 2(2002), pp. 37-42
[22]	K.G. Tonet, J.P.GorninskiConstr. Build.Mater., 40(2013), pp. 378-389
[23]	Q.W. Wang, J. Li, J.E.WinandyWood Sci. Technol., 38(2004), pp. 375-389
[24]	T. Ishii, H. Kokaku, A. Nagai, T. Nishita, M. KakimotoPolym.Eng. Sci., 46(2006), pp. 799-806
[25]	C. Formicola, A.D. Fenzo, M. Zarelli, M. Giordano, V. AntonucciPolym.Int., 60(2011), pp. 304-311
[26]	Y. Feng, G.E.McGuire, O.A. Shenderova, H. Ke, S.L. BurkettThin Solid Films, 615(2016), pp. 116-121
[27]	A.B. Morgan, M. GalaskaPolym.Avd. Technol., 19(2008), pp. 530-546
[28]	M. Jimenez, S. Duquesne, S. BourbigotThermochim.Acta, 449(2006), pp. 16-26
[29]	Y. Feng, S.L.BurkettJ. Vaccum Sci .Technol. B, 33(2015), p. 022004
[30]	K.R. Ravi, R.M. Pillai, K.R. Amaranathan, B.C. Pai, M. ChakrabortyJ.Alloys Compd., 456(2008), pp. 201-210
[31]	W. Wang, G.H. Wu, Q.D. Wang, Y.G. Huang, W.J.DingMater. Sci. Eng. A, 507(2009), pp. 207-214
[32]	T. Manabe, Y. Yamamoto, Y. HoshiyamaTrans.Am. Foundry Soc., 113(2005), pp. 1029-1037
[33]	O. Lashkari, S. Nafisi, R. GhomashchiMater.Sci. Eng. A, 441(2006), pp. 49-59
[34]	S. Nafisi, D. Emadi, M.T. Shehata, R. GhomashchiMater.Sci. Eng. A, 432(2006), pp. 71-83
[35]	S. Lun Sin, D. DubeMater.Sci. Eng. A, 386(2004), pp. 34-42
[36]	M.D. Sabatino, L. Arnberg, S. R?rvik, A. PrestmoMater.Sci. Eng. A,413-414(2005), pp. 272-276
[37]	Y.D. Kwon, Z.Y.LeeMater. Sci. Eng. A, 360(2003), pp. 372-376
[38]	M. Bleckmann, J. Gleinig, J. Hufenbach, H. Wendrock, L. Giebeler, J. Zeisig, U. DiekmannJ.Alloys Compd., 634(2015), pp. 200-207
[39]	H.H. Abbas, R.A.SalihChin. J.Polym. Sci., 27(2009), pp. 465-469
[40]	N. Guigo, A. Mija, R. Zavaglia, L. Vincent, N. SbirrazzuoliPolym.Degrad. Stabil., 94(2009), pp. 908-913
[41]	R.S. Dungan, J.B.Reeves IIIJ. Environ. Sci. Health A, 40(2005), pp. 1557-1567
[42]	M. Monti, H. Hoydonckx, F. Stappers, G. CaminoEur.Polym. J., 67(2015), pp. 561-569
[43]	X.G. Jiang, C.Y. Li, Y. Chi, J.H.YanJ. Hazard Mater., 173(2010), pp. 205-210
[44]	T. Ahamad, S.M.AlshehriArab. J.Chem., 7(2014), pp. 1140-1147
[45]	J.W. Fruehling, J.D.HanawaltTrans. Am.Foundry Soc., 77(1969), pp. 159-164
[46]	C.D. Blasi, C. Branca, A. GalganoPolym.Degrad. Stab., 92(2007), pp. 752-764
[47]	Q.W. Wang, J. Li, J.E.WinandyWood Sci. Technol., 38(2004), pp. 375-389
[48]	J. CampbellCastings(2nd ed.), Butterworth-Heinemann, Press, Oxford, England, 1993 (1993)