目的 探究水导激光加工金刚石/铜复合材料的去除机理。方法 采用单因素实验法对金刚石/铜复合材料进行单道划槽实验,并对水导激光加工金刚石/铜复合材料的去除过程进行研究分析。结果 水导激光加工金刚石/铜复合材料的去除机理为,在激光的热作用下,铜基体熔化而金刚石颗粒发生石墨化,在水射流的冲击作用下,熔融铜基体和金刚石颗粒表面的石墨层被机械剥离,加工过程中产生的等离子体冲击波可促进熔融铜和石墨层的排出。当铜基体和金刚石颗粒之间的去除深度差较大时,铜基体对金刚石颗粒的结合力下降,在热应力和水射流冲击力的作用下,出现金刚石颗粒脱落和铜基体边缘隆起的缺陷。通过单因素实验发现,增加脉冲能量、降低扫描速度和增加扫描次数可增加沟槽深度。沟槽宽度主要受脉冲能量的影响,随脉冲能量的增加而增加。材料去除率随脉冲能量、扫描速度和水射流压力的增加而增加,随加工次数的增加而减小。沟槽底部去除深度差随脉冲能量和扫描次数的增加呈上升趋势,随扫描速度和水射流压力的增加呈下降趋势,去除深度差可控制在31.4 μm以内。基于单因素实验研究,实现了高质量切割和微通道热沉的制备。结论 水导激光加工金刚石/铜复合材料具有热影响区小、可避免金刚石颗粒脱落的优势,可实现金刚石/铜复合材料的低锥度、低表面粗糙度切割和形貌均匀且可重复性良好的微通道热沉制备。 关键词：水导激光;金刚石/铜复合材料;单道划槽;去除机理;烧蚀形貌
Abstract
Diamond/Cu composites demonstrate exceptional potential for such applications due to their ultrahigh thermal conductivity and tailorable coefficient of thermal expansion matching semiconductor substrates. However, inherent processing challenges arise from the extreme hardness of diamond, chemical inertness, and interfacial thermal resistance within the composite matrix, often resulting in thermal degradation, diamond fracture, and particle delamination during conventional machining. Water-jet guided laser (WJGL) processing presents a novel solution in hard-to-process composites, offering extended working distances, minimized heat-affected zones, and reduced kerf taper angles. In the current situation that diamond/Cu composites are difficult to process and there is relatively little research on processing, it is necessary to study the removal mechanism of diamond/Cu composites processed by water-jet guided laser. In this paper, the removal mechanism of diamond/Cu composites was studied by single-pass grooving. The ablation mechanisms were analyzed with groove morphology variations under differing laser pulse energy. Single-factor experimental designs were subsequently employed to examine the effects of four key processing parameters (laser pulse energy, scanning speed, water-jet pressure, and scanning times) on groove formation. Comparative analysis of processing parameters revealed their differential impacts on groove depth consistency. Groove morphology was characterized by confocal microscopy for three-dimensional surface profiling and dimensional measurements. Scanning electron microscopy facilitated microstructural evaluation, while phase composition analysis of processed diamond particles was performed by micro-Raman spectroscopy. Material removal in diamond/Cu composites during water-jet guided laser processing arises from synergistic interactions between laser-induced thermal effects and hydrodynamic removal mechanisms. The copper matrix undergoes phase transformation via laser irradiation followed by hydrodynamic stripping. Plasma-mediated expulsion mechanisms enhance molten copper ejection. Diamond particle removal involves concurrent processes of thermal-induced graphitization and mechanical de-graphitization through water-jet interaction. When the difference in ablation depth between the copper matrix and diamond particles is large, the bonding force of the copper matrix to the diamond particles decreases. Under the action of thermal stress and the water-jet impact, defects such as bulges at the edge of the copper matrix molten pool and diamond particle shedding occur. Experimental results demonstrate that an increase in pulse energy, a reduction in scanning speed, and a higher number of scans contribute to an increase in groove depth. The groove width is primarily influenced by pulse energy and shows a positive correlation with its increase. The material removal rate increases with higher pulse energy, scanning speed, and water-jet pressure, but decreases with an increase in the number of scanning times. The ablation depth difference at the bottom of the groove exhibits an increasing trend with higher pulse energy and a greater number of scans, while it decreases with increasing scanning speed and water-jet pressure. The ablation depth differential can be controlled within 31.4 μm, and achieve nearly no taper cutting with no diamond particle shedding. The high depth-to-width ratio microchannel heat sink can be fabricated under the best processing parameters. The research results show that water-jet guided laser has superiority in processing diamond/Cu composites and can achieve the high-quality cutting of diamond/Cu composites and the preparation of microchannel heat sinks.
关键词
水导激光 /
金刚石/铜复合材料 /
单道划槽 /
去除机理 /
烧蚀形貌
Key words
water-jet guided laser /
diamond/Cu composites /
single-pass grooving /
removal mechanism /
ablation morphology
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基金
广东省重点领域研发计划项目（激光与增材制造专项）（2023B0909030003）; 广州市科学技术局基础研究计划（2025A04J3758）
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