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研究了铈含量和热处理工艺对原位合成Al-15Mg_2Si-Si复合材料组织与性能的影响规律。结果表明:未变质时,Al-15% Mg_2Si-Si复合材料中初生Mg_2Si呈粗大的树枝状;加入Ce变质剂后,初生Mg_2Si变为块状,尖角被钝化,分布均匀。当变质剂Ce含量为0.8%时,初生Mg_2Si的尺寸最细小,为14μm,比未变质时减小了82.1%,并且其力学性能最佳,其抗拉强度、条件屈服强度、伸长率分别为215 MPa、157.1 MPa、2.3%。Ce含量为0.8%的Al-15% Mg_2Si-Si复合材料,在510℃固溶8 h+175℃时效5 h效果最好,块状初生Mg_2Si相几乎接近圆形,共晶Mg_2Si和共晶Si呈细小的颗粒状分布在基体上,硬度比铸态提高了24.2%。
The effects of cerium content and heat treatment process on the microstructure and properties of Al-15Mg_2Si-Si composites were investigated. The results show that primary Mg 2 Si in Al-15% Mg 2 Si-Si composites is coarse dendritic when unmetamorphic, and primary Mg 2 Si becomes massive after penetration of Ce modifier, and the sharp corners are passivated and evenly distributed. When the Ce content of the modifier is 0.8%, the size of the primary Mg 2 Si is the smallest, which is 14 μm, which is 82.1% less than that of the unmodified one, and its mechanical properties are the best. The tensile strength, yield strength and elongation are respectively 215 MPa, 157.1 MPa, 2.3%. Al-15% Mg 2 Si-Si composites with Ce content of 0.8% have the best effect after solution treatment at 510 ℃ for 8 h and aging at 175 ℃ for 5 h. The primary Mg 2 Si phase is nearly circular, eutectic Mg 2 Si and eutectic Si In the form of small particles distributed on the substrate, the hardness increased by 24.2% compared with as-cast.