Longitudinal Seam Failure in Extruded AZ31 Alloy


Article Preview

Research is currently being conducted on the feasibility of hydroforming extruded magnesium tubes to integrate multiple parts into a single hydroformed section. Among other applications, such sections would reduce the weight of both cars and planes, particularly when used in the vehicle frame. This would lead to either reduced fuel costs, or the ability to carry an increased payload. Magnesium generally has limited ductility, which in the case of the current extruded tubes is even further reduced at the extrusion seams. These are locations where the material flow separates and rejoins during extrusion and are unavoidable when a hollow profile die is used. When the tubes were stressed in a circumferential direction, tube ruptures consistently occurred along the extrusion seams of the tubes. This led to the current project, an inquiry into the exact cause of failure at these locations. The creation of irregularities at the seams, such as precipitate dispersions, local texture changes, grain size changes and entrained material, is discussed. These irregularities are considered together with their roles in producing the failures. The results are summarized and the most fruitful directions for future work are outlined.



Advanced Materials Research (Volumes 15-17)

Edited by:

T. Chandra, K. Tsuzaki, M. Militzer and C. Ravindran




J. Hiscocks et al., "Longitudinal Seam Failure in Extruded AZ31 Alloy", Advanced Materials Research, Vols. 15-17, pp. 439-444, 2007

Online since:

February 2006




[1] W. Callister: Materials Science and Engineering; an introduction (John Wiley & Sons Inc., 2000).

[2] A. Mwembela, H.J. McQueen: Met. Soc., Light Metals 2002 (2000), p.915.

[3] A.A. Luo, H.I. Kaplan et al., eds: Magnesium Technology 2000 (2000), p.89.

[4] International Magnesium Association: Magnesium Die Castings (McLean, VA 1991).

[5] K.U. Kainer, Magnesium Alloys and Technologies; (Wiley-vch Company, GmbH 2003).

[6] A. Galiyev, O. Sitdikov and R. Kaibyshev: Mater. Trans Vol. 44 No. 4 (2003), p.426.

[7] S. Pradip: Aluminum Extrusion Technology, (ASM International, Ohio, 2000).

[8] J. Rijkom and P.H. Bolt: Proc. 7 th Int. Al. Ext. Tech. Seminar, Vol. 1. (2000), p.249.

[9] S. Kalpakjian: Manufacturing Engineering and technology (Addison Wesley, 1995).

[10] A. Mwembela and H.J. McQueen: Light Met. Proc. and App., (CIMM, Montreal, 1993) p.523.

[11] W. Blum, P. Weidinger, B. Watzinger, R. Sedlacek, R. Rosch and H. Haldenwanger: Z. Metallkde., v. 88, (1997), p.636.

[12] P. Zang, B. Watzinger, Q. Kong and W. Blum: Key Engineering Mat., Vol. 171 No. 1-4, (2000), p.609.

[13] P. Zang, B. Watzinger and W. Blum: Phys. Stat. Sol. A, Vol. 175, (1999), p.481.

[14] W. Blum, B. Watzinger and P. Zang: Adv. Eng. Mat. Vol. 2, (2000), p.349.

[15] W. Blum. P. Zang, B. Watzinger and B. Grossman: Mat. Sci. Eng. A, Vol. 319-321 (2001), p.735.

[16] H. McQueen and E. Konopleva: Magnesium Technology 2001, (TMS-AIME, PA, 2001).

[17] T.B. Massalski, Binary Alloy Phase Diagrams, (ASM, Ohio, 1990).