Fabrication of High Aluminum Content Mg alloys using a Horizontal Twin Roll Caster
This study was aimed for investigating of manufacturing high aluminum content Mg alloys using a horizontal twin roll caster. Recently, weight saving has been key issues for lighter transport equipments as well as electronic componen t parts. As alternative materials to aluminum alloys, developin g magnesium alloy with higher strength has been expected. Normally hi gh Aluminum content Mg alloy has poor ductility and is difficul t to be rolled because of its high strength. However, twin roll casting pr ocess is suitable for manufacturing wrought Mg alloys because materials can be cast directly from molten metal. In this study, manufact uring of high aluminum content magnesium alloy sheet using the roll casting process has been carried out. Effects of manufactur ing parameter, such as roll velocity, pouring temperature and roll gap, on casting was investigated. A microscopic observation of the crys tals of cross section of as cast strip as well as rolled strip was conduc ted. Keywords—AZ91, AZ111, AZ121, Magnesium alloys, Twin roll casting
Mathematical Modeling of the Twin Roll Casting Process for Magnesium Alloy AZ31
.................................................................................................................................. iii Acknowledgements ................................................................................................................. v Dedication ............................................................................................................................... vi Table of
Recalculation of Mass Defects
THE well-known mass defect curve of the old nuclear scheme calculated with regard to α-particles and protons presented a difficulty with its minimum of binding energy for tin and an increasing portion between tin and lead. On the other hand, the mass defect values against protons give a rather smoothly decreasing curve.1 As has already been pointed out,2 the number of α-particles must be considerably reduced from the point of view of the new scheme, which does not admit any electrons in nuclei, but only neutrons and protons (presumably joined as α-particles). The curve of mass defect against protons and neutrons (perhaps with a single ‘central’ α-particle) is very similar to the old curve against protons, but decreases less rapidly. Clearly the new mass defect values relatively to α-particles, neutrons and protons must lie somewhere between the old values computed relative to protons and α-particles respectively (because the number of α-particles is decreased). We may emphasise that this new mass defect curve shows no increasing portion between tin and lead. For illustration we give two typical values: Old: 50Sn124 = 31α + 12&#38;epsiv;; mass defect = 0.158 (in mass units); 82Pb208 = 52α + 22&#38;epsiv;; mass defect = 0.035. New: 50Sn124= 25α + 24ω (ω = neutron); mass defect = 0.304; 82Pb208 = 41α + 44ω; mass defect = 0.366.