| In order to save materials and energy, the study and development on lightcastings has been an important research filed and developing direction. As thelightest metal structure materials, magnesium alloy has low density, high specificstrength and specific stiffness,good damping characteristic,excellent machinenobility and cast ability,etc. So more and more magnesium alloy products havebeen used in automobile,communication and aerospace industries. However, thefurther development and commercial application of magnesium alloys have beenlimited because of its low elastic modulus, poor tensile strength and creep resistingespecially at elevated temperature, as well as low wear resistance etc. Despite ofthe increasingly ingoing application of magnesium alloys and growing interest inmagnesium alloys, Because AM60 alloy is one of the most popular applicativemagnesium alloy, Although it has good toughness, it has poor tensile properties,specially used at elevated temperature. Common alloys are generally unsuitable foruse above 120℃, the higher temperature properties can't meet the requirements ofmany automobile applications, which limit its applications. so in the present work,we put light on the effect of RE addition in magnesium alloy about alloy'sproperties at room temperature.In the present work, as-cast magnesium alloys AM60 with RE addition wereprepared. The effect of RE content and heat treatment on the microstructure andtensile properties at room of AM60 alloys, are studied, which will offer sometheoretical foundations for expanding applications of magnesium alloys.RE are important alloying element to magnesium alloys. With additions of RE,the microstructure of as-cast magnesium alloys AM60 alloy were refined obviously.A rod-like inter metallic phase_Al11Nd3 phase was observed and the volume of theβ -phase(Mg17Al12) somewhat decreased. More RE addition caused furtherdeceasing of theβ-phase and coarsening of Al11RE3.RE improved hardness and tensile properties of AM60 alloys. As cast,hardness of the magnesium alloys AM60 had different extent and tensile propertiesincreased with increasing of Nd contents at room temperature. The ultimate tensilestrength, yield strength and elongation of alloys with 1.5wt% addition of REreached a high value, and then decreased with more RE additions. That's all causedby the wafer skilled,the second phase reference and the increase on volume andquantity of the new phase_ Al11Nd3.The influence to mechanical properties of as casting AM60, and AM60+xNdalloys are studied under various elevated temperatures. The results show that themechanical properties of as casting AM60 and AM60+xNd are improvedsignificantly at elevated temperature because of the higher melting point and thethermal stability of rod-like inter metallic phase_Al11Nd3 phase. The β-Mg17Al12phase has melted into base α-Mg, so the critical stress σc of the Frieda equation iscalculated and compared in the investigated as casting alloys under the differenttemperature. The σc of as casting AM60+xNd alloy is higher than that of AM60alloy at the same temperature. This represents that the moving of dislocations inAM60+xNd alloy is more difficult than in AM60 alloy.Form of fracture of as casting magnesium AM60 is quasi-cleavage at roomtemperature. Fracture of alloys have characters of tearing ridge and dimples withRE addition, and has more dimples with elevated temperature. Under the elevatedtemperature, cleavage surfaced disappeared and dimples can be seen in AM60alloys with RE, showing ductile fracture.
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