Ni对Al-Si-Cu-Ni-Mg过共晶活塞合金组织和力学性能的影响

Effects of Ni on Microstructure and Mechanical Properties of Al-Si-Cu-Ni-Mg Hypereuctic Piston Alloy

通过金属型铸造制备了Al-Si-Cu-Ni-Mg过共晶铝硅合金,结合扫描电镜和能谱仪对合金的组织进行分析。在室温和高温下对该合金进行力学性能测试,研究了Ni元素对铸造Al-Si-Cu-Ni-Mg过共晶铝硅合金组织和力学性能的影响,分析了该合金在高温下的断裂机理。结果表明,随着Ni含量的增加,合金组织中主要富Ni相经历了从Al_(7)Cu_(4)Ni到Al_(3)CuNi再到Al_(3)Ni的变化,富Ni相体积分数不断增大。在室温下,随着Ni含量的增加,合金的力学性能变化趋势为先下降后上升;在200、300℃下,合金的抗拉强度随Ni含量的增加而提高,伸长率有所下降。300℃时,Ni对合金的屈服强度有明显的提升效果。

Al-Si-Cu-Ni-Mg hypereutectic Al-Si alloys were prepared by permanent mold casting.The microstructure of the alloy was analyzed by SEM and EDS,and the mechanical properties were measured at room temperature and high temperature.The effects of Ni content on the microstructure and mechanical properties of as cast Al-Si-Cu-Ni-Mg hypereutectic Al-Si alloys were investigated.The fracture mechanism of the alloy at high temperature was analyzed.The results show that with the increase of Ni content,the major Ni-rich phase in the alloy undergoes the change from Al_(7)Cu_(4)Ni to Al_(3)CuNi,and to Al_(3)Ni,and the volume fraction of Ni-rich phase increases gradually.At room temperature,with the increase of Ni content,the mechanical properties of the alloy decrease firstly before increase.At 200℃and 300℃,the tensile strength of the alloy increases with the increase of Ni content and the elongation decreases.At 300℃,the improvement of Ni content has an obvious effect on the yield strength.