Modifying Effect of Al-Ti-C-P Master Alloy on Hypereutectic Al-Si Alloy

摘要

Al-Ti-C-P master alloy has been successfully fabricated by SHS-melting technology. Microstructures and phase constituent of Al-Ti-C-P master alloy were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and EDS. The results show that Al-Ti-C-P master alloy comprises TiAl_3, TiC, AlP and α-Al matrix. After adding 2.0 wt% Al-Ti-C-P master alloy, microstructure and mechanical properties (after T_6 treating) of ZL117 alloy has been improved dramatically: The average grain size of primary silicon decreases from 260 to 35 μm, edges and angles of primary silicon are passivated, the morphology of eutectic silicon changes from large needle-like one to fine rod-like or particle-like one, and the microstructures are noticeably refined; Room temperature tensile strength changes from 168 to 260 MPa while elevated temperature tensile strength (at 300°C) varies from 88 to 125 MPa. Impact toughness and macro-hardness(HB) increases to 17 J/cm~2 and 97 from the original 6.5 J/cm~2 and 92.