Effects of Liquid/Solid Volume Ratio on Microstructure and Mechanical Properties of A356/Q345 by Compound Casting
Q345 steel was hot-dip plated with A356 aluminum alloy at 700 ℃,and A356/Q345 bimetallic composites were prepared by liquid-solid compound casting.Effects of liquid/solid volume ratio(5.54,6.91,9.93,13.3)on the microstructure characteristics,thickness,phase composition and mechanical properties of A356/Q345 composites were investigated.The results reveal that a descirable metallurgical bond layer is formed at the interface,and the thick-ness of bonding layer is increased from 17.18 pm to 22.04 pm with the increase of liquid/solid volume ratio,which are mainly composed of Al9Fe2Si2,Al8Fe2Si and Al5Fe2 phases.The microhardness of aluminum matrix and steel matrix remains basically stable,while that of bonding layer is increased slightly with the increase of liquid/solid volume ratio.The average microhardness of bonding layer is 356.89 HV,which is far higher than that of aluminum matrix and steel matrix.The tensile strength and shear strength of composites are increased firstly and then decreased,reaching the maximum value of 351.4 MPa and 48.3 MPa,respectively,with the liquid/solid volume ratio of 9.93,indicating desir-able comprehensive mechanical properties.
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