(西北工業(yè)大學(xué) 凝固技術(shù)國家重點(diǎn)實(shí)驗(yàn)室，西安 710072)
摘 要: 通過在金剛石表面鍍鈦來改善金剛石和鋁基體之間的弱界面結(jié)合，并用氣壓浸滲法制備體積分?jǐn)?shù)為60%的鍍鈦金剛石/鋁復(fù)合材料。研究鍍鈦后金剛石顆粒的物相組成、不同鍍層厚度和不同顆粒尺寸下復(fù)合材料的熱導(dǎo)率；用H-J和DEM模型預(yù)測復(fù)合材料的熱導(dǎo)率，并將預(yù)測結(jié)果與實(shí)驗(yàn)值進(jìn)行對比。結(jié)果表明，鍍鈦后金剛石顆粒的物相由金剛石、碳化鈦和鈦三相組成；隨著鍍層厚度的增加，界面?zhèn)鳠嵯禂?shù)減小，復(fù)合材料的熱導(dǎo)率減小；顆粒的尺寸越小，這種變化趨勢越明顯；相對于H-J模型，DEM模型更能準(zhǔn)確地預(yù)測鍍鈦金剛石增強(qiáng)的復(fù)合材料的熱導(dǎo)率；通過計(jì)算得出鍍鈦金剛石/鋁復(fù)合材料的臨界鍍層厚度為1.5 μm，當(dāng)超過此臨界鍍層厚度時(shí)，鍍層反而不利于復(fù)合材料熱導(dǎo)率的提高。
關(guān)鍵字: 鍍鈦金剛石/鋁復(fù)合材料；鍍層厚度；熱導(dǎo)率；界面?zhèn)鳠嵯禂?shù)；氣壓浸滲
（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
