Zr基氮化物/金属Cu纳米多层膜的强韧化研究

Toughening and Strengthening of Zirconium Nitride/Mental Cu Nano-Multilayer

多层结构可以提高材料的强度、弹性模量和韧性。当尺寸减小到纳米量级时,性能将产生飞跃变化。首先探讨了多层结构提高强度、弹性模量和韧性等性能的基本原理,然后阐明了纳米尺度效应及理论,重点以过渡族金属氮化物ZrN纳米多层膜为例,研究了氮化物/金属(ZrN/Cu)纳米多层膜、ZrAlN纳米复合膜以及ZrAlN/Cu纳米多层膜的强韧化性能。结果表明,ZrN/Cu纳米多层膜的断裂韧性约是二元ZrN薄膜的2倍。当纳米多层膜的Cu单层厚度为20 nm时,多层膜的K_(IC)值最高。ZrAlN复合膜的断裂韧性与Al含量密切相关,当Al原子分数为23%时,薄膜的K_(IC)值达3.17 MPa·m^(1/2),其硬度>40 Gpa,Al原子分数为47%的薄膜的K_(IC)值则降低到1.13 MPa·m^(1/2),其硬度降低至17.1 GPa。与ZrN/Cu纳米多层膜和ZrAlN复合膜相比,以ZrAlN层和Cu层为调制结构制备的ZrAlN/Cu纳米多层膜具有最高的硬度和最好的韧性。

Muhilayer film can improve the strength, elastic modulus and toughness of materials markedly, the perform- ance of film will be significantly improved if multilayer period is reduced to nanometer scale. This paper studied the tough- ening and strengthening of ZrN/Cu nano-muhilayer film, ZrA1N composited film and ZrAIN/Cu nano-multilayer film, the morphology of films were investigated by FESEM, the microstructure was studied by XRD, XPS and TEM. The plastic deformation characteristic of thin films were analyzed from loading/unloading curves measured by nano-indentation meth- od. The results show that： the fracture toughness（K1C） of ZrN/Cu is 2 times that of ZrN film. ZrN/Cu has the maximum Kic value when Cu mono-layer thickness is 20 nm. For ZrA1N composite film with 23% AI（ atomic percent） , the Klc is 3.17 MPa ·m1/2, hardness is greater than 40 GPa, while for ZrA1N with 47% AI（ atomic percent） , the Kjc is 1. 13 MPa · m1/2 , hardness is 17. 1 GPa. ZrAIN with 23% Al（atomic percent） is more ＂hard and tough＂ than ZrAIN with 47% Al （atomic percent） , showing its properties are remarkly affected by A1 raito in composite film. ZrAIN/Cu nano-muhilayer film has best hardness and toughness compared with ZrN/Cu nano-multilayer film and ZrA1N composited film.