热压烧结制备CuFeCoCr复合材料的显微组织及热物理性能研究

Investigation of microstructure and thermophysical properties of hot-pressed CuFeCoCr composite

摘要:

本研究利用相图计算的CALPHAD方法和超音雾化制粉技术,在CuFeCoCr体系中设计并制备了一系列微米级复合粉体。通过热压烧结方法在烧结温度为950 °C,烧结压力为45MPa的工艺条件下成功获得块体复合材料。实验研究了块体复合材料中Cu含量对显微组织,热导率,热膨胀系数以及显微硬度的影响。研究结果表明：CuFeCoCr块体复合材料均由fcc富铜相和fcc富铁钴铬相组成。该系列复合材料经600 °C时效处理8小时后,其热膨胀系数变化范围为5.75~11.45×10_^-6 K_^-1；热导率变化范围为42.2~107.4 W.m_^-1.K_^-1。其中Cu₅₅(Fe_0.37Cr_0.09Co_0.54)₄₅复合材料表现出良好的综合性能,即其热膨胀系数和热导率分别为 6.88×10_^-6 K_^-1 和 91.09 W.m_^-1.K_^-1,这可以与电子封装中半导体材料的热膨胀系数相匹配。此外,本研究所制备的复合材料的显微维氏硬度均高于Cu/Invar复合材料。

Abstract:

In this paper, series micro-scale powders with composite microstructure in CuFeCoCr system were successfully designed and fabricated by using CALPHAD (Calculated of Phase Diagrams) approach and gas atomization method, respectively. The bulk CuFeCoCr composites were produced by hot pressing technique at 950℃ under a pressure of 45MPa. The effect of Cu content on the microstructure, coefficients of thermal expansion (CTE), thermal conductivity (TC) and micro-hardness (H_V) were systematically studied. The results show that the CuFeCoCr composites present two separate fcc phases (Cu-rich and FeCrCo-rich phase) microstructure. After annealing at 500 °C for 8 h, the CTE of the composites ranged from 5.75 to 11.45×10^_-6 K^_-1 and TC varied from 42.2 to 107.4 W.m^_-1.K^_-1. Particularly, the Cu₅₅(Fe_0.37Cr_0.09Co_0.54)₄₅ composite exhibits excellent comprehensive properties, i.e. CTE of 6.88×10^_-6 K^_-1 and TC of 91.09 W.m^_-1.K^_-1,which matches with the semiconductor in electronic packaging. In addition, all the prepared composites exhibit a higher H_V than that of Cu/Invar composite.