Analysis of Microstructures and Mechanical Properties of Die-Casting Mg-Al Based Alloy Strengthened by Yb
The effect of Yb on the microstructures and mechanical properties of die-casting Mg-9Al-0.6Zn-0.2Mn alloys containing varied contents of xYb(x=0,0.5％,1.0％and 1.5％,mass fraction)was studied.X-ray diffraction,microhard-ness test,tensile properties tests,optical microscopy,scanning electron microscopy,transmission electron microscope and en-ergy disperse spectroscopy were used to analyze microstructures and mechanical properties.The results show that new Al2Yb phase is formed near the grain boundary after Yb is added to the die-casting Mg-9Al-0.6Zn-0.2Mn alloys.The microstructures of the alloy are composed of α-Mg,continuous network β-Mg17Al12 phase and Al2Yb phase,and obviously refined with the in-crease of Yb content.The alloy with 1％Yb has the best comprehensive mechanical properties at room temperature and high temperature(150 ℃)and the alloy with 1.5％Yb has the highest microhardness.The improvement of the mechanical proper-ties is mainly due to the grain boundary strengthening caused by the aggregation of the newly formed thermal stability Al2Yb phase at the grain boundary,grain refinement strengthening caused by grain refinement and the solid solution strengthening caused by rare earth addition.
NETL
NSTL
万方数据
