Microstructure, Mechanical Properties and Fracture Behavior of As-Extruded Zn-Mg Binary Alloys

doi:10.1007/s40195-017-0585-4

Abstract

Abstract:

In the present work, Zn-(0-1)Mg (wt%)alloys were prepared by casting and indirect extrusion at 200 and 300 °C, respectively. With Mg addition, both the size and amount of second phase Mg₂Zn₁₁ increased, and the equiaxed grains were significantly refined. The extrusion temperature had little influence on Mg₂Zn₁₁, but the grains were refined at low extrusion temperature. For the alloys extruded at 200 °C, as Mg content increased, the tensile yield strength (TYS)increased from 64 MPa for pure Zn to 262 MPa for Zn-1Mg; the elongation increased from 14.3% for pure Zn to 25% for Zn-0.02Mg and then decreased to 5% for Zn-1Mg. For the alloys extruded at 300 °C, as Mg content increased, the TYS increased from 67 MPa for pure Zn to 252 MPa for Zn-1Mg, while the elongation decreased from 11.7% to 2%. The alloy extruded at 200 °C exhibited higher TYS and elongation than the corresponding alloy extruded at 300 °C. The combination of grain refinement and second phase Mg₂Zn₁₁ contributed to the improvement in the TYS, and the grain refinement played a major role in strengthening alloy. Zn-0.02Mg and Zn-0.05Mg alloys extruded at 200 °C show a mixture of cleavage and ductile fracture corresponding to higher elongation, while the other alloys show cleavage fracture.

Key words: Zn-Mg binar alloy, Indirect extrusion, Microstructure, Mechanical property, Fracture behavior

Li-Qing Wang, Yu-Ping Ren, Shi-Neng Sun, Hong Zhao, Song Li, Gao-Wu Qin. Microstructure, Mechanical Properties and Fracture Behavior of As-Extruded Zn-Mg Binary Alloys[J]. Acta Metallurgica Sinica (English Letters), 2017, 30(10): 931-940.

Figures/Tables 10

Table 1 Mg content of the as-extruded Zn-Mg binary alloys (wt%)

Alloys	Mg
Zn-0.02Mg	0.024
Zn-0.05Mg	0.056
Zn-0.2Mg	0.216
Zn-0.5Mg	0.464
Zn-1Mg	0.975

Fig. 1 Optical micrographs of the Zn-Mg binary alloys on longitudinal section: a pure Zn at 200 °C, b Zn-0.02Mg at 200 °C, c Zn-0.05Mg at 200 °C, d Zn-0.2Mg at 200 °C, e Zn-0.5Mg at 200 °C, f Zn-1Mg at 200 °C, g pure Zn at 300 °C, h Zn-0.02Mg at 300 °C, i Zn-0.05Mg at 300 °C, j Zn-0.2Mg at 300 °C, k Zn-0.5Mg at 300 °C, l Zn-1Mg at 300 °C

Fig. 2 Variation of the average grain size of the Zn-Mg binary alloys with Mg content

Fig. 3 SEM-BSE morphologies of the Zn-Mg binary alloys on longitudinal section: a Zn-0.02Mg at 200 °C, b Zn-0.05Mg at 200 °C, c Zn-0.2Mg at 200 °C, d Zn-0.5Mg at 200 °C, e Zn-1Mg at 200 °C, f Zn-0.02Mg at 300 °C, g Zn-0.05Mg at 300 °C, h Zn-0.2Mg at 300 °C, i Zn-0.5Mg at 300 °C, j Zn-1Mg at 300 °C

Fig. 4 X-ray diffraction patterns of the Zn-1Mg alloys extruded at 200 and 300 °C

Fig. 5 Tensile stress-strain curves of the Zn-Mg binary alloys extruded at a 200 °C, b 300 °C. Tensile properties of the as-extruded Zn-Mg binary alloys: c strength and d elongation

Fig. 6 Fracture morphologies of the Zn-Mg binary alloys extruded at 200 °C: a Zn, b, c low and high magnification of Zn-0.02Mg, d, e low and high magnification of Zn-0.05Mg, f Zn-0.2Mg, g Zn-0.5Mg, h Zn-1Mg

Fig. 7 Fracture morphologies of the Zn-Mg binary alloys extruded at 300 °C: a Zn, b Zn-0.02Mg, c Zn-0.05Mg, d Zn-0.2Mg, e Zn-0.5Mg, f Zn-1Mg

Table 2 Respective contributions of the strengthening mechanisms to the Zn-Mg binary alloys extruded at 200 °C

Alloys (wt%)	Zn	Zn-0.02Mg	Zn-0.05Mg	Zn-0.2Mg	Zn-0.5Mg	Zn-1Mg
d_g (μm)	112	45	24	16	9	9
d_S (μm)		0.5	0.8
f_S		0.0037	0.0092	0.037	0.092	0.183
σ₀ (MPa)	32.3	11
Δσ_g (MPa)	20.8	86.5	118.4	145	193.3	193.3
Δσ_S (MPa)	-	12.4-27.9	14.0-33.2	-	-	-
Calculated σ_y (MPa)	53.1	109.9-125.4	143.4-162.6	170.6	236.1	267.6
Tested σ_y (MPa)	64	132	152	179	227	262

Table 3 Respective contributions of the strengthening mechanisms to the Zn-Mg binary alloys extruded at 300 °C

Alloys (wt%)	Zn	Zn-0.02Mg	Zn-0.05Mg	Zn-0.2Mg	Zn-0.5Mg	Zn-1Mg
d_g (μm)	203	117	85	38	14	11
d_S (μm)		0.5	0.8
f_S		0.0037	0.0092	0.037	0.092	0.183
σ₀ (MPa)	32.3	11
Δσ_g (MPa)	15.4	53.6	62.9	94.1	155.0	174.9
Δσ_S (MPa)	-	12.4-31.6	13.7-37.7	-	-	-
Calculated σ_y (MPa)	47.7	77.0-96.2	87.6-111.6	121.6	201.3	252.5
Tested σ_y (MPa)	67	103	122	170	209	252

References

[1]	R. Hansch, R.R. Mendel, Curr. Opin. Plant Biol. 129, 259(2009)
[2]	L. Rink, Zn in Human Health (IOS Press, Amsterdam, 2011)
[3]	D. Vojtech, J. Kubasek, J. Capek, I. Pospisilova, Mater. Technol. 49, 877(2015)
[4]	D.E. Talbot, J.D. Talbot, Corrosion Science and Technology (CRC Press, Boca Raton, 2007)
[5]	P.K. Bowen, J. Drelich, J. Goldman, Adv. Mater. 25, 2577(2013)
[6]	D. Vojtech, J. Kubásek, J. ?erák, P. Novák, Acta Biomater. 7, 3515(2011)
[7]	J. Kubasek, D. Vojtech, E. Jablonska, I. Pospisilova, J. Lipov, T. Ruml, Mater. Sci. Eng., C 58, 24(2016)
[8]	X.W. Liu, J.K. Sun, F.Y. Zhou, Y.H. Yang, R.C. Chang, K.J. Qiu, Z.J. Pu, L. Li, Y.F. Zheng, Mater. Des. 94, 95(2016)
[9]	X.W. Liu, J.K. Sun, Y.H. Yang, F.Y. Zhou, Z.J. Pu, L. Li, Y.F. Zheng, Mater. Lett. 165, 242(2016)
[10]	J. Kubasek, I. Pospisilova, D. Vojtech, E. Jablonska, T. Ruml, Mater. Technol. 48, 623(2014)
[11]	H. Gong, K. Wang, R. Strich, J.G. Zhou, J. Biomed. Mater. Res. B 103, 1632(2015)
[12]	H.F. Li, H.X. Xie, Y.F. Zheng, Y. Cong, F.Y. Zhou, K.J. Qiu, X. Wang, S.H. Chen, L. Huang, L. Tian, L. Qin, Sci. Rep. 5, 10719(2015)
[13]	H.F. Li, H.T. Yang, Y.F. Zheng, F.Y. Zhou, K.J. Qiu, X. Wang, Mater. Des. 83, 95(2015)
[14]	N.S. Murni, M.S. Dambatta, S.K. Yeap, G.R.A.Froemming , H. Hermawan,Mater. Sci. Eng.,C 49, 560(2015)
[15]	P. Ghosh, M. Mezbahul-Islam, M. Medraj, CALPHAD 36, 28(2012)
[16]	J.H. Liu, C.X. Huang, S.D. Wu, Z.F. Zhang, Mater. Sci. Eng., A 409, 117(2008)
[17]	F.J. Humphreys, M. HatherlyRecrystallization and Related Annealing Phenomena, Elsevier Science,New York, 2004)
[18]	N.G. Ross, M.R. Barnet, A.G. Beer, Mater. Sci. Eng., A 619, 238(2014)
[19]	B.Q. Shi, R.S. Chen, W. Ke, J. Alloys Compd. 509, 3357(2011)
[20]	L. Cao, R.S. Chen, E.H. Han, J. Alloys Compd. 472, 234(2009)
[21]	Y. Chen, N. Gao, G. Sha, S.P. Ringer, M.J. Starink, Acta Mater. 109, 202(2016)
[22]	Z.L. Liu, D. Qiu, F. Wang, J.A. Taylor, M.X. Zhang, Metall. Mater. Trans. A 47, 830(2016)
[23]	R. Armstrong, I. Codd, R.M. Douthwaite, N.J. Petch, Philos. Mag. 7, 45(1962)
[24]	M. Mabuchi, K. Higashi, Acta Mater. 44, 4611(1996)
[25]	J.W. Liu, X.D. Peng, M.L. Li, G.B. Wei, W.D. Xie, Y. Yang, Mater. Sci. Eng., A 655, 331(2016)
[26]	C.C. Kammerer, S. Behdad, L. Zhou, F. Betancor, M. Gonzales, B. Boesl, Y.H. Sohn, Intermetallics 67, 145(2015)
[27]	V.A. Serban, C. Codrean, M. Voda, D. Chicot, X. Decoopman, Mater. Sci. Eng.,A 605, 294(2014)
[28]	A. Deschamps, A. Bigot, F.L. Vet, P. Auger, Y. Brechet, D. Blavette, Philos. Mag. A 81, 2391(2001)