Abstract:

Under the initial rolling temperatures of 250 to 400 ℃, AZ31B magnesium alloy sheets are rolled by four different rolling routes. Microstructures of the rolled sheets are observed by Axio Imager A2m Metallographic Microscope, and room-temperature tensile properties are detected by WDW-E100D Electronic Universal Testing Machine. Then the formabilities, microstructures and mechanical properties of the rolled sheets are analyzed by comprehensively considering different initial rolling temperatures and rolling routes. The results of the research indicate that: obvious correlation is revealed between rolling process and microstructures and mechanical properties of the rolled magnesium alloy sheets. Along with the rising of initial rolling temperature, yield strength and tensile strength of rolled sheets are gradually decreased, and elongation is increased; edge cracks have been greatly reduced by different routes of cross-rolling, and edge crack disappears at the initial rolling temperature of 400 ℃; the distributions of microstructures of RD-ND section and TD-ND section are similar, and unimodal normal distribution of the grain size is presented; The uniformity of the grain size distribution can be effectively improved and anisortropy can be weakened by different routes of cross-rolling; uniform, fine and equiaxial grain microstructures can be produced by multi-pass cross rolling process.

Key words: microstructure and mechanical property, rolling route, AZ31B magnesium alloy