在Al-12Si-2Cu合金中加入0.10～0.25wt%混合稀土金属,对合金的重力铸造试样和压力铸造试样进行了机械性能和金相组织检验,并测定了液态合金的流动性和凝固过程中的热裂应力。试验结果表明:此合金中加入0.10～O.25wt%的混合稀土金属,则可使金相组织中优先析出初生α-Al,使共晶Si相由长针状变短棒状或颗粒状,因而可改善合金的强度、明显提高延伸率;同时显著提高Al-12Si-2Cu合金的热裂应力。 In the Al-12Si-2Cu alloy by adding 0.10 ~ 0.25wt% mixed rare earth metals, the alloy gravity casting and pressure casting samples were tested for mechanical properties and microstructure, and measured the liquid alloy fluidity and solidification Thermal cracking stress in the process. The experimental results show that adding 0.10 ~ 0.25wt% mischmetal to this alloy can preferentially precipitate primary α-Al in the microstructure and make the eutectic Si phase become shorter or long rod-like or rod-like. Therefore, Can improve the strength of the alloy, significantly improve the elongation; while significantly improving the Al-12Si-2Cu alloy thermal cracking stress.