(西北工業(yè)大學(xué) 凝固技術(shù)國(guó)家重點(diǎn)實(shí)驗(yàn)室, 西安 710072)
摘 要: 采用氣壓浸滲法制備金剛石/碳化硅/鋁復(fù)合材料，研究復(fù)合材料的斷口形貌以及界面反應(yīng)，測(cè)試復(fù)合材料的熱膨脹性能。結(jié)果表明：金剛石表面Ti鍍層使得其選擇性粘附不同于未鍍鈦金剛石的，而在各個(gè)面上均粘附有Al，金剛石與基體間有著良好的界面結(jié)合，斷裂方式以基體斷裂為主，其界面反應(yīng)后，Ti以Al3Ti和Ti-Al-Si等金屬間化合物的形式析出，提高金剛石/鋁界面的結(jié)合強(qiáng)度，降低復(fù)合材料的熱膨脹系數(shù)；隨著金剛石顆粒粒徑的增大，金剛石和碳化硅顆粒間粒徑比的增大增加了整個(gè)復(fù)合材料的體積分?jǐn)?shù)，從而降低了其熱膨脹系數(shù)；金剛石顆粒粒徑增大導(dǎo)致熱膨脹系數(shù)升高。這兩方面共同影響復(fù)合材料的熱膨脹系數(shù)，但前者起主導(dǎo)作用；金剛石和碳化硅在不同配比下的熱膨脹系數(shù)隨著復(fù)合材料中碳化硅含量的增加逐漸增大，Terner模型與Kerner模型的計(jì)算平均值能較好地預(yù)測(cè)實(shí)驗(yàn)結(jié)果。
關(guān)鍵字: 復(fù)合材料；金剛石；碳化硅；熱膨脹
（State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China）
Abstract:The diamond/SiC/Al composites were produced by gas pressure infiltration, and the morphology of the fracture surfaces, interface reactions and coefficients of thermal expansion of the composites were investigated. The results show that the aluminum matrix adheres to all the faces of Ti-coated diamond, which is different from the selective adhesion phenomenon observed in the uncoated diamond composites, the interface bonding between diamond and aluminium matrix is strengthened due to the existence of Ti coating on the diamond surface, the main fracture mechanism of the composite is ductile fracture. After interface reactions, the intermetallic compounds, such as Al3Ti and Ti-Al-Si deposits, improve the diamond/Al interfacial bonding strength and decrease the thermal expansion coefficients of the composites. With the diamond particle diameter increasing thermal expansion coefficients of composite decrease due to the increasing, the particle diameter ratio of diamond and silicon carbide, which leads to the increase of volume fraction of composites. The thermal expansion coefficients of composites decrease with the increase of the diamond particle size. The two factors are interacted, however, the first factor plays a dominant role. The thermal expansion coefficients increase with the SiC content increasing at different content ratios of diamond to SiC. The experimental results can be well predicted with the average results calculated by Terner and Kerner models.
Key words: composites; diamond; SiC; thermal expansion
