ABSTRACT
The increasing extreme precipitation events and destructive žoods under global warming, which are known to be largely irreversible on timescales of many centuries [1], have recently been realized to stem from the human-caused greenhouse gas emissions [2-4]. As stated in the Kyoto global warming agreement [5], lightweighting in ground vehicles and aircraft is today deemed as one of the most effective strategies to improve fuel economy and reduce anthropogenic environment-damaging emissions [6-11]. Advanced high-strength steels, aluminum alloys, magnesium alloys, and polymers are being used to reduce vehicle weight and the subsequent CO2 emissions, but substantial reductions could be further achieved by a greater application of magnesium alloys [5,6,9,12,13]. Magnesium has thus been considered as a strategic ultralightweight material in the automotive and
13.1 Introduction .......................................................................................................................... 647 13.1.1 Why Magnesium ....................................................................................................... 647 13.1.2 Magnesium in Aerospace Industry ...........................................................................648 13.1.3 Signi™cance of Fatigue of Mg Alloys .......................................................................648
13.2 Microstructures .....................................................................................................................649 13.2.1 Cast Mg Alloys .........................................................................................................649 13.2.2 Extruded Mg Alloys ................................................................................................. 650 13.2.3 Welded Joints of Mg Alloys ...................................................................................... 652
13.3 Deformation Mechanisms.....................................................................................................654 13.4 Fatigue Properties of Mg Alloys ........................................................................................... 657
