S Of Silicocalcium On The Micro-Tructure And Properties Of AM60 Magnesium Alloy

Magnesium alloy has the advantages of light-weight, high strength/weight ratio, high stiffness / weight ratio, high damping property and electromagnetism shielding property and so on. It has bright promise for magnesium alloy to be widely used in aviation and spaceflight, vehicle, electrommunication, and is regarded as the most promising green material of the 21st century. Following with the light-weight of automobiles, more and more automobiles' components are made from magnesium alloys, where the wheels have a special magnificence and effect for the weight-save of automobiles. But wheels should have both high strength and high toughness depending on their working environment, the magnesium alloys at present has not satisfied the requirement for material yet. AM60 and AZ91 are the most broadly used magnesium alloys in industry. AM60 alloy has a high ductility but its strength needs to be improved.The Si addition to magnesium alloys causes an increased fluidity of the molten metal. The Mg₂Si formed by the addition of Si exhibits high melting point, high hardness, low density, high elastic modulus and low thermal expansion coefficient. But the existence of the coarse Chinese script type Mg₂Si phase can lead to the reduction of the mechanical properties of the alloys. Proper addition Ca to magnesium alloys can be efficient in refining the microstructure, and causes a morphological change in Mg₂Si particles from coarse Chinese script shape to a small polygonal type. Related investigations have revealed that the modification mechanism of Ca is polygonal type Mg₂Si particles nucleate from CaSi₂ particles. To import Si and Ca, many of the studies have been realized by Al-Si, Al-Ca or Mg-Ca master alloys. However, less work has been carried on importing Si and Ca by silicocalcium which is applied widely in steel-making.In this paper, four kinds of new AM60 alloy have been developed with silicocalcium. Effects and mechanism of silicocalcium addition on the microstructures and properties have been investigated using modern analysis and test facilities such as Optical Microscopy (OM), X-ray Difractometer(XRD) , Differential Scanning Calorimetric(DSC), Scanning Electron Microscopy(SEM) with Energy Dispersive Spectrometer (EDS) and...