( 1. 華中科技大學(xué) 塑性成形模擬及模具技術(shù)國家重點實驗室,
武漢 430074;
2. 三峽大學(xué) 機械與材料學(xué)院, 宜昌 443002;
3. 南京航空航天大學(xué) 材料科學(xué)與技術(shù)學(xué)院, 南京 210016)
摘 要: 采用真空燒結(jié)工藝制備Ti(C, N)基金屬陶瓷， 測定了材料的力學(xué)性能。 結(jié)果表明， 其力學(xué)性能與未加納米粉的金屬陶瓷相比， 硬度略有升高， 但橫向斷裂韌性提高了近一倍。 斷口形貌和微觀組織分析表明： 金屬陶瓷的斷口形貌與其強韌性有著密切的關(guān)系。 納米粉的加入降低了原始粉末的平均粒度， 使得金屬陶瓷硬質(zhì)相的粒度降低， 減小了晶粒間的平均自由程。 鑲嵌于大顆粒環(huán)形相和彌散分布于粘結(jié)相中的細小硬質(zhì)相顆粒， 對裂紋的形成和擴展起到阻礙作用， 會使金屬陶瓷因裂紋擴展途徑發(fā)生偏轉(zhuǎn)而增韌。
關(guān)鍵字: Ti(C, N)基金屬陶瓷； 斷口形貌； 增韌機理； 力學(xué)性能
（ 1. State Key Laboratory of Plastic Forming Simulation and Die and Mould Technology, Huazhong University of Science and Technology,
Wuhan 430074, China;
2. College of Mechanical and Materials Engineering,
China Three Gorges University, Yichang 443002, China;
3. College of Materials Science and Technology,
Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China）
Abstract: The Ti(C, N)-based cermets were produced by vacuum sintering technology, and the mechanical properties were measured. The results show that the hardness of nano-composite Ti(C, N)-based cermets slightly increases, while the transverse rupture strength (TRS) increases by a factor of two times compared with micron cermets. The analysis of appearance of fracture and microstructure indicates that there is compact relation between appearance of fracture and toughness. With the addition of nano-structured powders, the mean particle size of raw powders decreases, the microstructure becomes finer and distributes evenly, and the average distance between grains reduces. Some small grains are found to be embedded in binder and the rim phases of big grains obstruct the form and extend of crack. The experiment results indicate that the toughening mechanisms of nano-composite cermets is crack deflection toughening.
Key words: Ti(C, N)-based cermets; appearance of fracture; toughening mechanisms; properties
