The P ＋ Sr ＋ Ce compound modification technologies of as-cast Al-21Si-1.5Cu-1.5Ni- 2.5Fe- 0.5Mg alloy were investigated by means of orthogonal test. Orthogonal test results show that 3% （CaH2PO4 ＋ 2CASO4）＋ 0.2%...The P ＋ Sr ＋ Ce compound modification technologies of as-cast Al-21Si-1.5Cu-1.5Ni- 2.5Fe- 0.5Mg alloy were investigated by means of orthogonal test. Orthogonal test results show that 3% （CaH2PO4 ＋ 2CASO4）＋ 0.2%Sr ＋ 0.2%Ce is the optimum additive of modification treatment which can fine eutectic and primary silicon also can change the form of rich-iron phase at same time. The needle form of rich-iron phase is Al9FeSi3, which is prored by X-ray diffraction analysis and X-ray energy spectrum analysis. After compound modification treatment, the needle form of rich-iron phase disappeared and the fish bone form of rich-iron and rich-Ce phase that is AlsCeFe emerged. Both at room temperature and at 300℃, the tensile strength of the alloy after the modification treatment with the optimum additive is 30% lager than that of the alloy unmodified. Observed by SEM, the brittle intercrystalline tensile fracture changed into a blended one in which has many dimples.展开更多
文摘The P ＋ Sr ＋ Ce compound modification technologies of as-cast Al-21Si-1.5Cu-1.5Ni- 2.5Fe- 0.5Mg alloy were investigated by means of orthogonal test. Orthogonal test results show that 3% （CaH2PO4 ＋ 2CASO4）＋ 0.2%Sr ＋ 0.2%Ce is the optimum additive of modification treatment which can fine eutectic and primary silicon also can change the form of rich-iron phase at same time. The needle form of rich-iron phase is Al9FeSi3, which is prored by X-ray diffraction analysis and X-ray energy spectrum analysis. After compound modification treatment, the needle form of rich-iron phase disappeared and the fish bone form of rich-iron and rich-Ce phase that is AlsCeFe emerged. Both at room temperature and at 300℃, the tensile strength of the alloy after the modification treatment with the optimum additive is 30% lager than that of the alloy unmodified. Observed by SEM, the brittle intercrystalline tensile fracture changed into a blended one in which has many dimples.
