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采用KBF4和K2ZrF4混合粉末与铝熔体反应制备镁合金用Al-5Zr-xB细化剂,利用光学显微镜、X射线衍射仪和扫描电镜,研究了Al-5Zr-xB镁合金细化剂的显微组织及其对AZ91D镁合金的晶粒细化作用。结果表明,Al-5Zr-xB细化剂中含有大量细小均匀的ZrB2粒子,ZrB2粒子团聚分布在α-Al晶界上。细化剂中的B含量越高,ZrB2粒子的数量越多,晶粒细化能力越强。添加0.2%的Al-5Zr-1.8B细化剂,可使AZ91D镁合金中的α-Mg晶粒细化至120μm,抗拉强度和伸长率分别提高至213 MPa和4.95%,与未添加Al-5Zr-1.8B细化剂相比,AZ91D镁合金的晶粒平均直径下降了63.4%,抗拉强度和伸长率分别提高了15.1%和30.3%。
The Al-5Zr-xB refiner was prepared by the reaction of KBF4 and K2ZrF4 mixed powders with aluminum melt. The effects of Al-5Zr-xB magnesium alloy refiner were studied by optical microscope, X-ray diffraction and scanning electron microscope Microstructure and Its Grain Refinement on AZ91D Magnesium Alloy. The results show that a large amount of fine and uniform ZrB2 particles are contained in the Al-5Zr-xB refiner, and the ZrB2 particles are agglomerated and distributed on the α-Al grain boundary. The higher the content of B in the refiner, the greater the number of ZrB2 particles and the stronger the grain refinement ability. The addition of 0.2% Al-5Zr-1.8B refiner can refine the α-Mg grains in AZ91D magnesium alloy to 120μm, increase the tensile strength and elongation to 213 MPa and 4.95% respectively, -5Zr-1.8B refiner, the average grain diameter of AZ91D magnesium alloy decreased by 63.4%, tensile strength and elongation increased by 15.1% and 30.3% respectively.