TiC/Al和SiC/Al中间合金对Mg-Al系合金晶粒的细化

Grain Refinement of TiC/Al and SiC/Al Master Alloy on Mg-Al Based Alloys

研制出两种新型的Mg Al系合金晶粒细化剂———Al 4%TiC和Al 10%SiC中间合金。结果表明:这两种中间合金对Mg Al系合金均有良好的晶粒细化作用。向AZ63合金中加入1%的TiC/Al中间合金可使其晶粒由原来的约2mm减小至250μm左右;向AZ31合金中加入0 5%的SiC/Al中间合金可使其晶粒由原来的约600μm减小至200μm左右。分析认为,表面覆有Al4C3过渡层的TiC和SiC颗粒可以作为α Mg的结晶核心,同时SiC颗粒本身也可以作为α Mg的异质结晶核心。大量异质结晶核心的存在是导致α Mg晶粒细化的主要原因。

TiC/Al and SiC/Al master alloys developed to refine the grains of Mg- Al alloys show that the satisfactory refining efficiency for Mg-Al alloys has b een achieved. For instance, the grain size of AZ63 decreases from 2000μm to 250 μm with addition of 1% TiC/Al master alloy and So does the AZ31 from 600μm to 200μm with addition of 05% SiC/Al master alloy.In addition, the TiC and SiC particles with Al4C3 transitional layer can serve the nucleating sites of α-M g during solidification.SiC particles can serve as the nuclei. Heterogeneous nuc leation is the main cause of the grain refinement of Mg-Al alloys.