The mathematical model of the mean flow stress for MgAl3Zn1Mn magnesium alloy

Purpose: The presented paper deals with method for determination of mean flow stress (MFS) which contributes to better knowledge of forming processes of hot formed magnesium alloys. Design/methodology/approach: An experiment leading to obtaining the model of the mean flow stress (MFS) of magnesium alloy AZ31 was realized in laboratory rolling mill. It resulted from mathematical and statistical processing of MFS values that these could be described by a simple function of just two independent variables - temperature (200 to 450°C) and equivalent height strain (approx. 0.2 to 0.7). The methods of the light microscopy for metallographic analyses were used. Findings: The increasing strain resulted in decreasing deformation resistance. The effect of equivalent strain rate (approx. 10-80 1/s) was negligible. The model describes the given relationship with good accuracy; a relative error of calculated MFS values does not exceed ±10%. Research limitations/implications: In future work an important relation between the MFS, the Zener-Hollomon parameter and the grain size will be determined. A significant influence of the deformation temperature on the average grain size after recrystallization was identified, while observing lower sensitivity of this parameter to an increased strain rate. Practical implications: The results of structural studies along with the devised thermomechanical model will be used to design the foundations of rolling technology for this group of alloys. The results of this paper are determined for research workers deal by development new exploitations of magnesium alloys. Originality/value: These results describe complex evaluation of properties magnesium alloys namely for determination of the values of mean flow stress (MFS) which contributes to better knowledge of forming processes of hot formed magnesium alloys and explain the structure developed used magnesium alloys after forming.