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为了消除铸态Cu-3Si-2Ni合金中枝晶偏析及非平衡组织对其加工性能的影响,分别在850~950℃、保温2~8 h条件下对比研究了该合金在均匀化下的元素分布、显微组织及性能变化规律。结果表明:随温度的升高及保温时间的延长,合金的偏析程度及非平衡第二相组织明显减少,合金综合力学性能均得以提高和改善,其中温度对均匀化效果的影响更为显著;在相同加热条件下,合金中Ni比Si的扩散速度更慢。并在此基础上利用扩散理论建立起相应的Ni元素均匀化动力学方程。经验证,实验值与理论计算结果基本吻合,获得该合金较佳的均匀化退火工艺为900℃×4 h。
In order to eliminate the dendritic segregation and unbalanced microstructure of the as-cast Cu-3Si-2Ni alloy, the effect of homogenization of the alloy under 850 ~ 950 ℃ and 2 ~ 8 h heat preservation was studied. Distribution, microstructure and properties of the law of change. The results show that with the increase of temperature and holding time, the degree of segregation and the non-equilibrium second phase microstructure decrease obviously, and the mechanical properties of alloy increase and improve. The effect of temperature on homogenization is more significant. Under the same heating conditions, the diffusion speed of Ni in alloy is slower than that of Si. On this basis, the diffusion kinetic equation of Ni element was established. It is verified that the experimental results are basically consistent with the theoretical calculation results, and the better homogenization annealing process of this alloy is 900 ℃ × 4 h.