Effect of Thermomechanical Processes on Twin Roll Casted Magnesium Alloy Sheets

Abstract

6 mm thick and 1500 mm wide magnesium alloy AZ31, AZ61, AZ91, AM50 and AM60 sheets were produced by twin roll casting technique. Sheets were homogenized between 350-475oC for 1-24 h. AZ31 sheets were rolled down to 1 mm by symmetrical warm rolling and asymmetric warm rolling. Age hardening was also performed on magnesium alloy AZ91 sheets. Specimens were aged at 100-300oC for up to 100 h. Characterization was performed by light microscope, scanning electron microscopy-energy dispersive spectrometry (SEM-EDS), transmission electron microscopy (TEM) and x-ray diffraction (XRD) after twin roll casting and also after each thermomechanical process including aging. Tensile tests and micro hardness tests were performed for mechanical properties. In addition to the room temperature tests, elevated temperature tensile tests were also performed at 100, 150, 200, 250, and 300oC at various deformation speeds. Forming limit diagram of the material was determined under warm forming condition.