Hostname: page-component-586b7cd67f-l7hp2 Total loading time: 0 Render date: 2024-11-27T02:45:11.614Z Has data issue: false hasContentIssue false
  • English
  • Français

Effect of precipitate shapes on fracture toughness in extruded Mg–Zn–Zr magnesium alloys

Published online by Cambridge University Press:  03 March 2011

Hidetoshi Somekawa ,
Alok Singh  and
Toshiji Mukai
Hidetoshi Somekawa*
Affiliation:
Structural Metals Center, National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 Japan
Alok Singh
Affiliation:
Structural Metals Center, National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 Japan
Toshiji Mukai
Affiliation:
Structural Metals Center, National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 Japan
*
a) Address all correspondence to this author. e-mail: [email protected]
Get access

Abstract

A commercial Mg–6 wt% Zn–0.5 wt% Zr (ZK60) alloy was used to investigate the effect of precipitate shapes on fracture toughness. The ZK60 alloy was extruded at a temperature of 653 K (extruded alloy). The extruded alloy was annealed at 633 K for 86.4 ks (annealed alloy), and then the annealed alloy was aged at 448 K for 100 ks (aged alloy). The average grain size in all the conditions was about the same, 13.5 ± 1.0 μm. The extruded and aged alloys had different shaped precipitates: spherical and rod shaped precipitates, respectively. The plane-strain fracture toughness KIC of the extruded, annealed, and aged alloys were estimated to be 22.4, 20.2, and 21.0 MPam1/2, respectively, by the stretched zone analysis. Transmission electron microscopy (TEM) observations showed that the deformation during the fracture toughness test was dominated by a dislocations on the basal slip planes in all the conditions. Such dislocations are commonly activated in magnesium alloys during the tensile and compression tests. The spherical shaped precipitates were found to be more effective than the rod shaped precipitates for improving the fracture toughness in the magnesium alloy.

Keywords

DislocationsMgToughness
Type
Articles
Information
Journal of Materials Research , Volume 22 , Issue 4 , April 2007 , pp. 965 - 973
Copyright
Copyright © Materials Research Society 2007

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1Barbagallo, S. and Cerri, E.: Evaluation of the K IC and J IC fracture parameters in a sand AZ91 magnesium alloy. Eng. Fail. Anal. 11, 127 (2004).CrossRefGoogle Scholar
2Lee, S., Lee, S.H., and Kim, D.H.: Effect of Y, Sr, and Nd additions on the microstructure mechanism of squeeze-cast AZ91-X magnesium alloys. Metall. Mater. Trans. A 29, 1221 (1998).CrossRefGoogle Scholar
3Purazrang, K., Kainer, K.U., and Mordike, B.L.: Fracture toughness behavior of a magnesium alloy metal-matrix composite produced by the infiltration technique. Composite 22, 456 (1991).CrossRefGoogle Scholar
4Sasaki, T., Somekawa, H., Takara, A., Nishikawa, Y., and Higashi, K.: Plane-strain fracture toughness on thin AZ31 wrought magnesium alloy sheets. Mater. Trans. 44, 986 (2003).CrossRefGoogle Scholar
5Somekawa, H., Osawa, Y., and Mukai, T.: Effect of solid-solution strengthening on fracture toughness in extruded Mg–Zn alloys. Scripta Mater. 55, 593 (2006).CrossRefGoogle Scholar
6ASM Specialty Handbook: Magnesium and Magnesium Alloys, edited by Avedisian, M.M. and Baker, H. (ASM International, Materials Park, OH, 1999) 163.Google Scholar
7ASM Specialty Handbook: Magnesium and Magnesium Alloys, edited by Davis, J.R. (ASM International, Materials Park, OH, 1993) 639.Google Scholar
8Somekawa, H. and Mukai, T.: Effect of grain size and texture on fracture toughness in magnesium and magnesium alloy, Magnesium Technology 2006 edited by Luo, A.A., Neelameggham, N.R. and Beals, R.S. (The Minerals, Metals and Materials Society, Warrendale, PA, 2006), p. 395.Google Scholar
9Somekawa, H. and Mukai, T.: Effect of texture on fracture toughness in extruded AZ31 magnesium alloy. Scripta Mater. 53, 541 (2005).CrossRefGoogle Scholar
10Somekawa, H. and Mukai, T.: Effect of grain refinement on fracture toughness in extruded pure-magnesium. Scripta Mater. 53, 1059 (2005).CrossRefGoogle Scholar
11Somekawa, H. and Mukai, T.: Fracture toughness in Mg–Al–Zn alloy processed by equal-channel-angular extrusion. Scripta Mater. 54, 633 (2006).CrossRefGoogle Scholar
12Somekawa, H. and Mukai, T.: Fracture toughness in ultra fine-grained magnesium alloy. Mater. Sci. Forum 503–504, 155 (2006).CrossRefGoogle Scholar
13Somekawa, H., Singh, A., and Mukai, T.: Deformation structure after fracture toughness test in Mg–Al–Zn alloys processed by equal-channel-angular extrusion. Philos. Mag. Lett. 86, 195 (2006).CrossRefGoogle Scholar
14Knott, J.F.: Micromechanisms of fibrous crack extension in engineering alloys. Mater. Sci. 14, 327 (1980).Google Scholar
15Ohira, T. and Kishi, T.: Effect of iron content on fracture toughness and cracking processes in high strength Al–Zn–Mg–Cu alloy. Mater. Sci. Eng., A 78, 9 (1986).CrossRefGoogle Scholar
16Hahn, G.T. and Rosenfield, A.R.: Metallurgical factors affecting fracture toughness of aluminum alloys. Metall. Mater. Trans. A 6, 653 (1975).CrossRefGoogle Scholar
17Ludtka, G.M. and Laughlin, D.E.: The influence of microstructure and strength on the fracture mode and toughness of 7XXX series aluminum alloys. Metall. Mater. Trans. A 13, 411 (1982).CrossRefGoogle Scholar
18Sasaki, T., Somekawa, H., Takara, A., Nishikawa, Y., and Higashi, K.: Influence of second phase particles on fracture toughness in AZ31 magnesium alloys. Key Eng. Mater. 261–263, 369 (2004).CrossRefGoogle Scholar
19Somekawa, H. and Mukai, T.: Fracture toughness in an extruded ZK60 magnesium alloy. Mater. Trans. 47, 995 (2006).CrossRefGoogle Scholar
20Watanabe, H., Mukai, T., Ishikawa, K., and Higashi, K.: Low temperature superplasticity of a fine-grained ZK60 magnesium alloy processed by equal-channel-angular extrusion. Scripta Mater. 46, 851 (2002).CrossRefGoogle Scholar
21Lapovok, R., Cottam, R., Thomson, P., and Estrin, Y.: Extraordinary superplastic ductility of magnesium alloy ZK60. J. Mater. Res. 20, 1375 (2005).CrossRefGoogle Scholar
22Ma, C., Liu, M., Wu, G., Ding, W., and Zhu, Y.: Tensile properties of extruded ZK60-RE alloys. Mater. Sci. Eng., A 349, 207 (2003).CrossRefGoogle Scholar
23Mukai, T., Yamanoi, M., Watanabe, H., Ishikawa, K., and Higashi, K.: Effect of grain refinement on tensile ductility in ZK60 magnesium alloy under dynamic loading. Mater. Trans. 42, 1177 (2001).CrossRefGoogle Scholar
24Galiyev, A., Kaibyshev, R., and Gottstein, G.: Correlation of plastic deformation and dynamic recrystallization in magnesium alloy ZK60. Acta Mater. 49, 1199 (2001).CrossRefGoogle Scholar
25Watanabe, H., Moriwaki, K., Mukai, T., Ohsuna, T., Hiraga, K., and Higashi, K.: Materials processing for structural stability in a ZK60 magnesium alloy. Mater. Trans. 43, 775 (2003).CrossRefGoogle Scholar
26Clark, J.B.: Transmission-electron-microscopy study of age hardening in a Mg–5 wt% Zn alloy. Acta Mater. 13, 1281 (1965).CrossRefGoogle Scholar
27ASTM E399, Standard Test Method for Plane-Strain Fracture Toughness of Metallic Materials (American Society for Testing and Materials, West Conshohocken, PA, 2001).Google Scholar
28Massalski, T.B.: Binary Alloy Phase Diagrams, 2nd ed. (ASM International, Materials Park, OH, 1990), p. 2571.Google Scholar
29Nie, J.F. and Muddle, B.C.: Precipitation hardening of Mg–Ca(–Zn) alloys. Scripta Mater. 37, 1475 (1997).CrossRefGoogle Scholar
30Bettles, C.J., Gibson, M.A., and Venkatesan, K.: Enhanced age-hardening behavior in Mg–4 wt% Zn micro-alloyed with Ca. Scripta Mater. 51, 193 (2004).CrossRefGoogle Scholar
31Oh, J.C., Ohkubo, T., Mukai, T., and Hono, K.: TEM and 3DAP characterization of an age-hardened Mg–Ca–Zn alloy. Scripta Mater. 53, 675 (2005).CrossRefGoogle Scholar
32Nie, J.F., Gao, X., and Zhu, S.M.: Enhanced age hardening response and creep resistance of Mg–Gd alloys containing Zn. Scripta Mater. 53, 1049 (2005).CrossRefGoogle Scholar
33Spizing, W.A.: Electron microfractography. ASTM STP 453, 90 (1969).Google Scholar
34Higashi, K., Hirai, Y., and Ohnishi, T.: Relationship between fracture toughness and impurity elements in Al–Zn–Mg–Cu alloys. J. Jpn. Inst. Light Metals 35, 520 (1985).CrossRefGoogle Scholar
35Yoshinaga, H. and Horiuchi, R.: Deformation mechanisms in magnesium single crystals compressed in the direction parallel to hexagonal axis. Mater. Trans., JIM 4, 1 (1963).CrossRefGoogle Scholar
36Stohr, J.F. and Poirier, J.P.: Electron microscope study of pyramidal slip {11-22}〈11-23〉 in magnesium. Philos. Mag. 25, 1313 (1972).CrossRefGoogle Scholar
37Sheerly, W.F. and Nash, R.R.: Mechanical properties of magnesium monocrystals. Trans. Metall. Soc. AIME 218, 416 (1960).Google Scholar
38Koike, J., Kobayashi, T., Mukai, T., Watanabe, H., Suzuki, M., Maruyama, K., and Higashi, K.: The activity of non-basal slip system and dynamic recovery at room temperature in fine-grained AZ31B magnesium alloys. Acta Mater. 51, 2055 (2003).CrossRefGoogle Scholar
39Watanabe, H., Mukai, T., Sugioka, M., and Ishikawa, K.: Elastic and damping properties from room temperature to 673 K in an AZ31 magnesium alloy. Scripta Mater. 51, 291 (2004).CrossRefGoogle Scholar
40Kim, W.J. and Jeong, H.T.: Grain-size strengthening in equal-channel-angular-pressing processed AZ31 Mg alloys with a constant texture. Mater. Trans. 46, 251 (2005).CrossRefGoogle Scholar
41Nie, J.F.: Effects of precipitate shapes and orientation on dispersion strengthening in magnesium alloys. Scripta Mater. 48, 1009 (2003).Google Scholar
42Frost, H.J. and Ashby, M.F.: Deformation Mechanism Map (Pergamon Press, Oxford, 1982), p. 44.Google Scholar
43Morozumi, S.: Metals Handbook (Japan Institute of Metals, Tokyo, 1990), p. 940.Google Scholar
44DeHoff, R.T. and Rhines, F.N.: Quantitative Microscopy (McGrawHill, New York, 1968).Google Scholar