Evaluation of Hot Tensile Behavior of Fine-Grained Mg–9Al–1Zn Alloy Tube Processed by Severe Plastic Deformation

Abstract

In the present study, parallel tubular channel angular pressing (PTCAP) process was implemented to as cast Mg–9Al–1Zn magnesium alloy tubes via different number of passes at 300 °C. Mechanical properties and microstructure evolution of the tubes were investigated at room and elevated temperatures. The results showed that an increase in strain leads to a higher strength, hardness, and elongation at room temperature. A significant grain refinement was achieved. It was decreased to 4 µm for a third pass processed tube from an initial value of 150 µm. Strength increased notably to about 92 % after the second pass PTCAP process. Increase in the strength after first pass PTCAP was 56 %. Elongation relatively increased at room temperature, too. Microvoids and microcracks appeared in the third pass processed specimen. This led to a loss in strength and elongation in comparison with first and second pass processed samples. Two pass processed sample revealed ~178 % ductility in 400 °C tensile test. Hardness increased by about 77 % after third pass PTCAP process. The result of the mechanical properties and the microstructure were consistent with each other.