涂层与基底的热膨胀系数差对垂直界面的微裂纹的影响

Effect of the Difference of Thermal Expansion Coefficients between Ceramic Coatings and Metal on Vertical Micro-cracks

将陶瓷涂层/基体金属界面看作是在陶瓷基体中包含的圆柱形金属夹杂,在夹杂半径趋近于无穷大时的极限情形。给出了平面应变条件下圆形夹杂两侧的半裂纹的应力强度因子的解析表达式,让圆形夹杂的半径趋向无穷大,得到陶瓷涂层/基体金属界面的垂直微裂纹的有关结果。根据所得结果,分析了陶瓷涂层和金属材料的膨胀系数的差异对于其界面微开裂的影响,所得结论对于陶瓷涂层的设计和制备工艺等具有指导意义。

In this paper, the ceramic coating/metal interface is considered to be the limiting case of a cylindrical inclusion boundary, as the inclusion radius approaches to infinity. Under the conditions of plane strain, analytical exressions for the stress intensity factors of the half- cracks along the two sides of the circular inclusion are given. Leting the radius of the circular inclusion approach to infinite, it obtains the concerning results of the microcracks on ceramic coating/metal substrate interface. From these results, the effect of the difference between the thermal expansion coefficients of metals and ceramic coating on the microcracking of the ceramic/metal interface was analyzed. The conclusions of this paper will be helpful for the ceramic coating/metal design and technology.