Cu和La对Al-12.6Si合金微观组织和性能的影响

Effects of Cu and La on Microstructure and Properties of Al-12.6Si Alloy

研究了La加入量为0.3%时,铜质量分数(0.3%,0.8%,1.3%,1.8%和2.5%)对共晶铝硅合金(Al-12.6Si)微观组织和力学性能的影响.结果表明:当La的加入量为0.3%时,共晶硅由片状和针状变为点状和短棒状,达到了完全变质的状态.随着铜加入量的增加,合金中的Al2Cu相的数量增多、尺寸增加,合金的抗拉强度和硬度逐渐增大,延伸率有所下降;当Cu加入量为2.5%时,Al-12.6Si-2.5Cu-0.3La合金的抗拉强度为241.4MPa,延伸率为4.82%,硬度为83.9HV,与Al-12.6Si合金相比这些力学指标分别提高了58.1%,41.8%和30.9%,合金的力学性能得到了极大的改善.

A series of Al - Si eutectic alloys with different contents of Cu （0.3 % ,0.8 %, 1.3 %, 1.8 % and 2.5 % ） and 0.3 % La were investigated. The results showed that the morphology of eutectic silicon is transformed from acicular/lamellar to pointlike and short rodlike when the addition of La is 0.30 %, and the alloy reaches the best modification state. With the increasing of Cu content, the number and size of Al2Cu phases, the tensile strength and hardness increase, but the elongation decreases. When the addition of Cu is 2.5 % , the tensile strength, elongation and hardness of Al-12.6Si-2.5Cu-0.3La are 241.4 MPa, 4.82 % and 83.9 HV, respectively, which increase 58.1%, 41.8% and 30.9%, respectively, compared with those of Al-12.6Si alloy. The mechanical properties of Al-Si eutectic alloy are improved obviously.