The flow behavior modeling of AZ61 magnesium alloy at elevated temperatures considering the effects of strain rate and grain size

In this study, the hot deformation behavior of a magnesium alloy was investigated under various process conditions. Tensile testing experiments were performed to determine the effects of temperature, strain, and strain rate on the flow stress of the material. A new constitutive model was established to characterize the dynamic recrystallization of the magnesium alloy at elevated temperatures. The critical strain was evaluated based on the temperature-compensated strain rate to consider the work softening. The amount of high temperature softening due to dynamic recovery and dynamic recrystallization was formulated as a function of strain, strain rate, and temperature. It was demonstrated that the proposed model is able to predict the flow softening as well as the growing strain hardening of the material very accurately. The failure characteristics were also studied at different temperatures and strain rates. Finally, the grain size effect on the flow behavior of the material was discussed.

[1]  M. Barnett,et al.  Influence of grain size on the compressive deformation of wrought Mg–3Al–1Zn , 2004 .

[2]  J. Gittus.  The Mechanical Equation of State , 1987 .

[3]  Y. Prasad,et al.  Hot deformation behaviour of Mg–3Al alloy—A study using processing map , 2008 .

[4]  Z. Cui,et al.  Modelling of flow stress characterizing dynamic recrystallization for magnesium alloy AZ31B , 2008 .

[5]  Ali A. Roostaei,et al.  The high temperature flow behavior modeling of AZ81 magnesium alloy considering strain effects , 2012 .

[6]  Wenbin Li,et al.  Modeling of flow stress for magnesium alloy during hot deformation , 2010 .

[7]  B. Mordike,et al.  Magnesium: Properties — applications — potential , 2001 .

[8]  J. L. Haughlinton,et al.  Magnesium and its alloys , 1937 .

[9]  I. Polmear,et al.  Magnesium alloys and applications , 1994 .

[10]  K. Maruyama,et al.  The activity of non-basal slip systems and dynamic recovery at room temperature in fine-grained AZ31B magnesium alloys , 2003 .

[11]  S. Agnew,et al.  Plastic anisotropy and the role of non-basal slip in magnesium alloy AZ31B , 2005 .

[12]  Hirohiko Takuda,et al.  Modelling of formula for flow stress of a magnesium alloy AZ31 sheet at elevated temperatures , 2005 .

[13]  J. Nam,et al.  Investigations into the size effect on plastic deformation behavior of metallic materials in microcoining process , 2014 .

[14]  H. Mcqueen,et al.  Microstructural development in Mg alloy AZ31 during hot working , 1997 .

[15]  I. Hurtado,et al.  Tensile characterization and constitutive modeling of AZ31B magnesium alloy sheet over wide range of strain rates and temperatures , 2011 .

[16]  M. Sanjari,et al.  Modeling of high temperature rheological behavior of AZ61 Mg-alloy using inverse method and ANN , 2008 .

[17]  J. Rödel,et al.  Investigation of the effect of strain rate and temperature on the deformability and microstructure evolution of AZ31 magnesium alloy , 2009 .

[18]  N. Petch,et al.  The Cleavage Strength of Polycrystals , 1953 .