(西北工业大学 凝固技术国家重点实验室，西安 710072)
摘 要: 通过在金刚石表面镀钛来改善金刚石和铝基体之间的弱界面结合，并用气压浸渗法制备体积分数为60%的镀钛金刚石/铝复合材料。研究镀钛后金刚石颗粒的物相组成、不同镀层厚度和不同颗粒尺寸下复合材料的热导率；用H-J和DEM模型预测复合材料的热导率，并将预测结果与实验值进行对比。结果表明，镀钛后金刚石颗粒的物相由金刚石、碳化钛和钛三相组成；随着镀层厚度的增加，界面传热系数减小，复合材料的热导率减小；颗粒的尺寸越小，这种变化趋势越明显；相对于H-J模型，DEM模型更能准确地预测镀钛金刚石增强的复合材料的热导率；通过计算得出镀钛金刚石/铝复合材料的临界镀层厚度为1.5 μm，当超过此临界镀层厚度时，镀层反而不利于复合材料热导率的提高。
关键字: 镀钛金刚石/铝复合材料；镀层厚度；热导率；界面传热系数；气压浸渗
（State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China）
Abstract:Titanium coating on diamond surface was adopted to improve the weak interface bonding between diamond and aluminum matrix. The Ti-coated diamond/Al composites were fabricated by gas pressure infiltration with a 60% volume fraction of diamond. The phase composition of diamond after coating titanium and the thermal conductivity (TC) of Ti-coated diamond/Al composites under different coating thicknesses and different particle sizes were also studied. The predicted results of the H-J and DEM models were compared with the experimental values. The results show that, the diamond particles are composed of three phases: diamond, TiC and Ti; along with the increase of the coating thickness, interface heat transfer coefficient and TC of composites decrease, the smaller the particle, the more obvious the tendency. Compared with the H-J model, the DEM model gives more accurate predictions for Ti-coated diamond/Al composites. The critical coating thickness was calculated to be 1.5 μm for diamond/Al composites. When the coating thickness exceeds this critical value, the coating is detrimental to improving the TC.
Key words: Ti-coated diamond/Al composites; coating thickness; thermal conductivity; interface heat transfer coefficient; gas pressure infiltration
