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根据贝壳珍珠层的结构特点,以金属Ti层为软质层,对TiB_2陶瓷薄膜进行仿生增韧处理,并通过压痕法研究了Ti/Ti B_2仿生多层膜的断裂韧性。结果表明:随着调制比Λ(t_(TiB_2):t_(Ti))的增大,多层膜的断裂韧性先增大而后减小,当Λ为5时,多层膜的断裂韧度达到最大值(KIC=2.68 MPa·m~(1/2))。对于相同厚度的Ti B_2单层膜而言,断裂韧度值仅为0.76MPa·m~(1/2),也就是说,Ti/Ti B_2仿生多层膜可有效提高陶瓷层的断裂韧性。沉积在Ti6Al4V基体上的多层膜在断裂过程中进行能量释放以径向裂纹为主,以环形裂纹为辅。由于多层膜中Ti子层的周期性引入,有效缓解了Ti B_2薄膜的内应力;当裂纹扩展至Ti子层时,Ti层可对裂纹尖端起到很好的钝化作用,使裂纹扩展方向发生偏转。此外,多层膜的界面增多,也相应增大了裂纹扩展的阻力,提高了多层膜的断裂韧性。
According to the structural characteristics of the nacre shell, the TiB 2 ceramic film was bionic toughened with the metal Ti layer as the soft layer, and the fracture toughness of the Ti / Ti B 2 bionic multilayer film was studied by indentation method. The results show that the fracture toughness of the multilayers first increases and then decreases with the increase of the modulation ratio Λ (t TiB2: t Ti). When Λ is 5, the fracture toughness of the multilayers reaches Maximum (KIC = 2.68 MPa · m ~ (1/2)). For the same thickness of TiB_2 single-layer film, the fracture toughness value is only 0.76MPa · m ~ (1/2), that is, Ti / Ti B_2 bionic multilayer film can effectively improve the fracture toughness of the ceramic layer. The multilayer films deposited on the Ti6Al4V matrix are mainly released in the fracture process with radial cracks, supplemented by annular cracks. Due to the periodic introduction of Ti sublayers in multilayers, the internal stress of TiB_2 thin films can be effectively relieved. When the crack propagates to Ti sublayers, the Ti layer can passivate the crack tip very well, The direction of deflection. In addition, the interface of the multi-layer film increases, correspondingly increases the resistance of the crack propagation and improves the fracture toughness of the multi-layer film.