【摘要】 以市面常见的2种铜粉作为胎体原料，采用真空热压烧结工艺经900、950、1 000、1 050、1 100℃烧结制备金刚石（铬）/铜复合材料，分析材料性能随温度变化情况，对比研究不同铜粉制备的金刚石/铜复合材料的性能稳定性。结果表明，在致密程度上，A批（电解铜粉）枝晶状铜粉制备的复合材料在不同烧结温度下的致密度相对稳定，基本在91.5%；在热导率方面，A批材料的热导率最高可达228 W/(m·K)，相对高于B批材料的热导率；在力学性能方面，A批复合材料平均弯曲强度为195 MPa，相较于B批次材料提高了32%。相同工艺条件下，A批铜粉更适合用作复合材料的胎体原料。更多还原

【Abstract】 【Objective】 Diamond/Cu composites have attracted extensive interest as advanced thermal management materials owing to the combination of the ultrahigh thermal conductivity of diamond and the ductility of copper. Although interfacial modification and reinforcement parameters have been widely explored, the influence of matrix powder morphology on microstructural evolution and property development during sintering at different temperatures remains insufficiently clarified. In this work, the influence of copper powder morphology on densification behavior, mechanical properties, thermal conductivity, and microstructural evolution of diamond/Cu composites was investigated under identical composition and pressure conditions over a series of sintering temperatures.【Method】 Two commercially available high-purity copper powders with different particle morphologies were used as matrix materials, including an electrolytic dendritic powder and an atomized spherical powder. Chromiumcoated diamond particles with a fixed volume fraction were incorporated as reinforcement. Composite specimens were consolidated by vacuum hot-press sintering under controlled pressure within the typical processing window of Cu-based systems. Relative density was determined using the Archimedes method. Flexural strength was evaluated through three-point bending tests. Thermal diffusivity and specific heat were measured by laser flash analysis to calculate thermal conductivity. Fracture morphology, pore distribution, and interfacial characteristics were characterized by scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction. Theoretical thermal conductivity was further predicted using a differential effective medium model considering interfacial thermal resistance derived from acoustic mismatch theory.【Result】 Sintering temperature influences densification and property evolution in both composite systems. With the increase of the temperature, relative density and thermal conductivity first increase and then decrease, reflecting the competition between improved diffusion bonding and copper exudation at elevated temperatures. Copper powder morphology modifies this temperature-dependent behavior. Composites fabricated with dendritic electrolytic copper powder maintain more stable densification across the investigated temperature range and exhibit reduced copper overflow at high temperature. Although their relative density is moderately lower than that of spherical powder-based counterparts at certain intermediate temperatures, their flexural strength is consistently higher, reaching an average value of approximately 195 MPa, corresponding to an increase of about 32%. The dendritic matrix structure forms a more interconnected framework and results in distributed micro-scale porosity, which promotes crack deflection and localized plastic deformation during fracture. Thermal conductivity shows a similar nonmonotonic dependence on sintering temperature for both systems, with a maximum value of 228 W/(m·K) obtained for the dendritic powder-derived composites. However, the experimentally measured values remain below 60% of the theoretical prediction from the differential effective medium model. This result indicates that interfacial thermal resistance plays the dominant role in limiting heat transfer, whereas variation in copper powder morphology has a relatively minor influence on intrinsic thermal conduction.【Conclusion】 The performance evolution of diamond/Cu composites results from the combined effects of sintering temperature and matrix powder morphology. While interfacial thermal resistance remains the primary factor limiting thermal transport efficiency, copper powder morphology significantly affects temperature stability, fracture behavior, and processing robustness. Under identical fabrication conditions, electrolytic dendritic copper powder provides improved mechanical reliability and more stable sintering performance over the investigated temperature range. These findings provide insight into matrix material selection and process optimization for high-performance diamond/Cu thermal management composites.更多还原