锰含量对近共晶铝硅铜锰合金组织与耐热性的影响

Effect of Mn Content on Microstructure and Heat-resistance of Near Eutectic Al-Si-Mn-Cu Alloy

通过显微组织观察和高温力学性能测,试研究了Mn含量对近共晶Al-12%Si-4%Cu-x%Mn合金组织与耐热性的影响。结果表明,随着Mn含量的增加,铝硅铜锰合金铸态组织中的Al15Mn3Si2相数量不断增多,且初生Al15Mn3Si2相的形态逐渐从小的块状及不发达的树枝状,转变为发达的树枝状和细杆状。同时发现,添加元素Mn的S2(0.8%Mn)、S3(1.2%Mn)、S4(1.6%Mn)合金室温和高温抗拉强度均高于S1合金,说明在Al-12%Si-4%Cu合金中引入的富锰相Al_(15)Mn_3Si_2是有利于改善合金耐热性的,并且随着富锰相数量的增加,合金的高温抗拉强度不断增加。但S5(2.0%Mn)合金中的初生Al15Mn3Si2相大部分呈现发达的树枝状和细杆状,脆性很大,耐热性能反而不如S1合金的。

Effect of Mn content on the microstructure and heat-resistance of near eutectic Al-12%Si-4%Cu-x%Mn alloys was investigated by microstructure observation and high temperature tensile test. The results show that with the increasing of Mn content, the amount of Al15Mn3Si2 phase in the as-cast microstructure, and the morphology of the primary Al15Mn3Si2 phase are changed from small block or undeveloped dendrite to developed dendrite or slender rod. And it is found the alloys with Mn addition, S2（0.8%Mn）, S3（1.2%Mn） and S4（1.6%Mn） have more superior high temperature strength than the base alloy S1 without Mn addition, indicating that inducing Al15Mn3Si2 phase in Al-Si-Cu base alloy is in favor of the considerable improvement of the high temperature strength. However, S5 （2.0%Mn） alloy has a lower high temperature strength than that of S1 alloy due to the developed dendritic or slender rod-like primary Al15Mn3Si2 phase has high brittleness.