稀土元素对AZ31镁合金组织和力学性能的影响

Effect of Rare Earth on Microstructure and Mechanical Properties of AZ31 Magnesium Alloy

向AZ31镁合金中添加稀土Ce和复合添加Ce与Sb,测试和分析了合金的力学性能和组织。研究表明:合金相组成主要为α-Mg、CeSb以及Mg_(17)Al_(12);复合添加Ce和Sb可细化晶粒和有助于形成CeSb第二相,从而有效提高AZ31镁合金的力学性能。当Ce为1.5%,Sb为1.5%时,铸态合金室温抗拉强度为201.4 MPa,伸长率为12.6%,冲击韧度值为8.1 J·cm^(-2);经385℃热挤压成型后,合金室温抗拉强度为325.6 MPa,伸长率为22.3%,冲击韧度值为15.8 J·cm^(-2)。

On the basis of AZ31 magnesium alloy, a modified magnesium alloy used for automobile was designed by adding rare earth Ce and Sb as alloying elements. The mechanical properties, phases constituents and microstructure of the modified alloy were tested and analyzed, respectively. The results show that the alloy is composed of α-Mg, CeSb and Mg_(17)Al_(12). The addition of rare earth Ce and Sb simultaneously can refine grain size and is beneficial for the formation of secondary phase CeSb, thus the mechanical properties of the alloy is improved effectively. When the addition of 1.5% Ce and 1.5%Sb, the tensile strength, elongation and impact toughness of the as-cast alloy are 201.4 MPa, 12.6 % and 8.1 J·cm^(-2),respectively, at room temperature. After the alloy is hot-extruded at 385 ℃, the room-temperature tensile strength,elongation and impact toughness increase to 325.6 MPa, 22.3% and 15.8 J·cm^(-2), respectively.