引线框架材料Cu-3.5Ni-0.75Si-0.15Co合金组织性能研究

Microstructure and properties of lead frame material Cu-3.5Ni-0.75Si-0.15Co alloy

采用铸造、热轧、固溶、冷轧和时效的方法制备了Cu-3.5Ni-0.75Si-0.15Co合金,研究了合金硬度、电导率在制备过程中的变化及相应的组织演变规律。结果表明:铸态合金晶粒粗大,热轧过程中发生完全动态再结晶,固溶过程中Ni3Si2相充分溶解,冷轧造成了晶粒拉长和滑移带的出现,时效过程中主要沉淀相为Ni2Si相,有明显的层状结构;合金的硬度和电导率在固溶过程中明显下降,电导率在时效过程中逐渐上升,时效温度越高,合金电导率越高,在时效过程中硬度先快速升高后缓慢下降,温度越高,硬度下降速度越快;合金的抗拉强度在500℃时效2.5 h可以达到814 MPa,对应的电导率为26.1 MS/m。

The Cu-3.5Ni-0.75Si-0.15Co alloy was prepared by the process of cast, hot-rolling, solid solution, cold-rolling and aging. The hardness, electrical conductivity and the evolution of the corresponding microstructure were studied throughout the whole preparing process. The results show that the grains are coarse in cast process, complete dynamic re-crystallization occurs in the hot-rolling process, the second phase Ni3Si： dissolves completely in the solid solution process, elongated grains and slip bands appear in cold-rolling process, Ni：Si as the main precipitated phase appears an obvious layered structure in aging process. Hardness and electrical conductivity of the alloy decrease dramatically during solution process, but electrical conductivity increases gradually in the aging process. In the aging process, higher electrical conductivity corresponds to higher aging temperature, but hardness increases rapidly in the beginning and decreases gradually after reaching the maximum, higher aging temperature corresponds to faster hardness decrease. The tensile strength reaches 814 MPa after aging at 500 ℃ for 1.5 h with electrical conductivity reaching 26.1 MS/m.