The Effect of Specimen Size on the Dynamic Compressive Behaviour of Magnesium Alloy AZ31B

Abstract:

The specimen size has always been crucial in defining the materials behaviour and becomes more important when materials are subjected to high rates of loadings. In the current study, the effect of specimen size on the mechanical behaviour of AZ31B alloy has been investigated under dynamic compression using the Split Hopkinson Pressure Bar (SHPB) and results are presented. Specimens were made in different sizes with fixed slenderness ratio (l/d) of 0.5 and with bar to specimen diameter ratio varying between 0.47 and 0.79. When deformed at the same strain rate 1500±50s-1, the smaller specimens give higher stresses and smaller strains. The smaller size specimens give more uniform strain rate as compared to the larger size specimens. However, some spurious oscillations are observed in the stress-strain curves for smaller size specimens. The alloy shows higher hardening behavior for larger size specimen; the hardening exponent n is larger for larger size specimens.

• Periodical: Key Engineering Materials (Volumes 535-536)
• Pages: 141-144
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.535-536.141
• Online since: January 2013
• Authors: Jing Xiao, Dong Wei Shu
• Keywords: AZ31B, Dynamic Behavior, Specimen Size Effect, Split Hopkinson Pressure Bar (SHPB), Strain Hardening

References

[1] Gunasekera, J.S., J. Havranek, and M.H. Littlejohn, The effect of specimen size on stress-strain behaviour in compression, in J Eng Mater Technol Trans ASME(1982). pp.274-279.

DOI: 10.1115/1.3225076

[2] Gorham, D.A., An effect of specimen size in the high strain rate compression test, in J. Phys. IV France(1991). p. C3-411-C3-418.

DOI: 10.1051/jp4:1991358

[3] Meyer, L.W., Herzig, N., and Kruger, L., Size effects on flow stress and failure of Ti-6-22-22S and Al7075 over a wide range of strain rates in 11th Int. Conf. on Fracture(2005): Turin, Italy.