EXPERIMENTAL INVESTIGATIONS INTO THE DEFORMATION BEHAVIOR OF THIXOMOLDED Mg AZ61L SHEET ALLOY

摘要

Deformation behavior and formability limits of thixo-molded MgAZ61L alloy and regular Mg AZ61 alloy sheets (with similarchemical compositions except for Mn content) wereexperimentally investigated at elevated temperature. Tensile(uniaxial), hydraulic bulge (biaxial) tests as well as closed-diehydroforming tests were conducted to understand the materialbehavior at temperatures ranging from 25 °C to 300 °C and strainrates at 0.0013, 0.013 and 0.13 s~(-1). It was found that flow stressand the maximum plastic strain increased with increasingtemperature and decreasing strain rate. Closed-die warmhydroforming tests were also performed to determine the processwindow for the sheet alloy. Die cavity filling ratios and thinningof the sheet blanks were measured with non-contact opticalphotogrammetry. Results indicated that lower strain rates andhigher temperatures increase formability, particularly abovetemperatures of 200 °C.