【摘要】 以Al-20Si合金为研究对象,添加Cu-P和Al-RE中间合金对其进行变质处理,采用SEM扫描电镜、X射线衍射仪和光学金相显微镜分析变质处理对合金中Si相形貌的影响。结果表明,P与Al反应生成AlP化合物,可以作为初生Si相的异质形核质点,显著细化初生Si,稀土吸附固溶在Si相的生长台阶,使Al-20Si合金中Si相的晶格常数增大,X射线衍射图谱发生小角度偏移;随着变质时间延长,合金中板条状的初生Si变得细小圆润,平均晶粒尺寸由85.6μm减小至13.2μm,共晶Si由长针状转变为短杆状,弥散分布在基体中,硬度(HB)由68.5提升至80.8。更多还原

【Abstract】 Cu-P master alloy and Al-RE master alloy were added into Al-20 Si alloy to understand influence of modification treatment on microstructure of the alloy by SEM,X-ray diffractometer and optical metallographic microscope.The experimental results reveal that the AlP phase can be generated by reaction of P and Al as the heterogeneous nuclei of the primary silicon phase to effectively refine the primary silicon in the alloy.The rare earth elements are adsorbed and dissolved into the growth step of the Si phase,resulting in the increase of lattice constant of Si phase in the Al-20 Si alloy and the shift of X-ray diffraction pattern with a small angle.With the increase of modification time,the average grain size of primary silicon is decreased from 85.6μm to 13.2μm.The eutectic silicon phase is changed from long needle to short rod shape with uniform distribution in the matrix.The hardness(HB)is increased from68.5 to 80.8.更多还原