Publication details

Authors: Shen, J.; Yin, W.; Kondoh, K.; Jones, Tyrone L.; Kecskes, L. J.; Yarmolenko, S. N.; Wei, Q. 
Title: Mechanical behavior of a lanthanum-doped magnesium alloy at different strain rates 
Type: Journal Article 
Publisher: Materials Science and Engineering: A 
Year: 2015 
Volume: 626 
Issue: 
Start Page: 108 
End Page: 121 
DOI: 10.1016/j.msea.2014.12.061 
WEB-link: http://www.sciencedirect.com/science/article/pii/S0921509314015615 
Abstract: The mechanical behavior of a lanthanum doped Mg alloy, AZXE7111, (Mg7Al1Zn1Ca1La, all in wt%) extruded at different temperatures has been investigated under both quasi-static (strain rate ~1103 s1) and dynamic (strain rate ~4103 s1) compressive loading. Comparison has been made against the experimental results of two conventional Mg alloys, AZ91E and WE43. It was observed via transmission electron microscopy (TEM) that the nanoscale intermetallic compounds of Al2Ca and Al11La3, have presumably formed during the hot extrusion process. These compounds are believed to contribute significantly to the strength by reducing the grain size and acting as dislocation barriers. Additionally, twinning has been considered as the main mechanism for the higher strain hardening rate at high strain rates than that at low strain rates. It has been found that the ultimate strength of the alloy is only ~10% higher at dynamic loading rate than at quasi-static loading rate. Localized micro-shear fracture was observed and adiabatic shear mode was suggested by further examination of dynamically loaded specimens. The shear localization is further discussed in detail and it is suggested that reduced strain hardening rate is responsible for shear localization and subsequent fracture at both low and high strain rates. 
Keywords: Mg alloy, Mechanical properties, Adiabatic shear band (ASB), Strain rate sensitivity (SRS), High strain rate behavior